MSK

Question 1

Stress Fracture

Answer 1

Fracture resulting from the mismatch of bone strength and chronic mechanical force. They come in two flavors (A) Fatigue, and (B) Insufficiency.

Question 2

Pathologic Fracture

Answer 2

You will sometimes hear people use this term synonymously with “Insufficiency
Fracture”. However, for the purpose of
multiple choice this term will most likely
refer to a fracture through a lvtic bone lesion.

These lytic lesions can be mets or be benign primary bone lesions (like an ABC, or Bone Cyst).

Question 3

Open Fracture (Compound Fracture):

Answer 3

A fracture associated with an open wound. Typically these will go to the OR for reduction and washout - given the obvious risk for infection.

Tuft Fractures (finger tip fracture) with disruption o f the nail plate are considered “open” fractures - and although the typically won’t go to the OR they do get antibiotics (whereas an intact nail bed often won’t).

Question 4

Fatigue Fracture

Answer 4

(sometime simply called a “stress fracture”).

Abnormal stress on Normal Bone.

Classic Scenario - Insane (but kinda hot) Type A Female Cross Country Runner - literally runs until her legs & feet break in half.

Question 5

Insufficiency Fracture

Answer 5

Normal stress on Abnormal bone.

Classic Scenario - Old lady with horrible osteoporosis breaks her back (compression fracture) by walking down a few steps. She blames Obama for the fracture.

Question 6

Phases of Fracture Healing

Overview

Answer 6

Physiology PhDs will describe 3 phases o f bone healing (Inflammatory, Reparative, and Remodeling). From a Radiologist’s perspective the most important thing to understand about this process is that around 7-14 days granulation tissue will be forming between the bone fragments. This results in an increased lucency o f the fracture site related to bone resorption.

In other words, a healing fracture will be MORE LUCENT at 7-14 days.

This explains the disclaimer cowardly Radiologists throw out when they are afraid they missed a fracture “Consider Repeat in 7-10 days, ” The idea is that in 7-10 days, you should be able to see the fracture line , if one is p re s e n t, because o f the increase in bone lucency that occurs normally in the healing process.

Question 7

Fracture healing

overview

Answer 7

In general, bones heal in about 6-8 weeks, but is location dependent. Healing is the fastest in the phalanges (around 3 weeks), and the slowest is either the tibia or femoral neck/shaft - depending on what you read(around 2-3 months).

Question 8

Phalanges healing

Answer 8

fast: 3 weeks

Question 9

Tibia healing

Answer 9

slow: 10 weeks

Question 10

Everything else healing

Answer 10

6-8 weeks

Question 11

Delayed Union

Answer 11

fracture not healed within the expected time period (but still might). Some sources will say “twice as long as expected”

Question 12

Non-Union

Answer 12

fracture is not going to heal without intervention. Some sources will say “6-9 months.’The classic locations are the scaphoid, anterior tibia, and lateral femoral neck.

Question 13

Mal-Union

Answer 13

This is union in poor anatomic position (healed crooked as a politician).

Question 14

Risk Factors For Abnormal Healing ( Delayed and Hon-Union)

Vitamin D deficiency

Answer 14

Vitamin D plays a vital role in
calcium uptake and metabolism.
Vitamin D deficiency is actually
the most common vitamin
deficiency in America
(supposedly).

Question 15

Risk Factors For Abnormal Healing ( Delayed and Hon-Union)

Gastric bypass

Answer 15

Having your gut rewired results
in altered calcium absorption
(causes secondary
hyperparathyroid and stripping
of calcium from bones) and
therefore higher rates of nonunion.

Question 16

Risk Factors For Abnormal Healing ( Delayed and Hon-Union)

Drugs/MEds

Answer 16

Tobacco (Smoking or Chewing)
NSA1DS
Prednisone (steroids)

Question 17

THIS v s THAT-C om p re s s iv e Side vs T e n s ile Side:

Answer 17

• Fractures of the Compressive side are constantly pushed back together - these do well.
• Fractures of the Tensile side arc constantly pulled apart - these are a pain in the ass to heal.

Question 18

Tibial Stress Fx

Answer 18

This is the most common site o f a stress fracture in young athletes.

These arc most common on the compressive side (posterior medial) in either the proximal or distal third.

Less common are the tensile side (anterior) fractures, and these favor the mid shaft. They arc bad news and don’t heal -often called “dreaded
black lines.’”

Question 19

Femoral Stress Fx

Answer 19

Fractures along the compressive (medial) side are more common, typically seen in a younger person along the inferior femoral neck.

Fractures along the tensile (lateral) side arc more common in old people.

Question 20

SONK (S p o n tan eo u s O s te o n e c ro s is o f th e K ne e)

overview

Answer 20

This is totally named wrong, as it is another type of insufficiency fracture. You see this in old ladies with the classic history o f “sudden pain after rising from a seated position.” Young people can get it too (much less common), usually seen after a meniscal surgery.

Question 21

SONK (S p o n tan eo u s O s te o n e c ro s is o f th e K ne e)

key factoids

Answer 21

• It’s an insufficiency fracture (NOT osteonecrosis) think SINK not SONK
• Favors the medial femoral condyle (area o f maximum weight bearing)
• Usually unilateral in an old lady without history o f trauma
• Associated with meniscal injury

Question 22

N a v icu la r S t r e s s F ra c tu r e

Answer 22

You see these in runners who run on hard surfaces. The thing to know is that ju st like in the wrist (scaphoid), the navicular is high risk for AVN.

Question 23

March fracture

Answer 23

This is a metatarsal stress fracture which is fairly common. Classically seen in military recruits that are marching all day long.

Question 24

Calcaneal Stress Fracture

Answer 24

The calcaneus is actually the most fractured tarsal bone. The fractures are usually intra-articular (75%). The stress fracture will be seen with the fracture line perpendicular to the trabecular lines.

You’ll rue the day you crossed me Trebek—ular Lines.

Question 25

High risk stress fractures

Answer 25

Femoral neck transverse patellar fx anterior tibial fx (midshaft) 5th metatarsal talus tarsal navicular sesamoid great toe

Question 26

Lowe risk stress fractures

Answer 26

Femoral neck (compressive side) longitudinal patellar fx posterior medial tibial fracture 2nd and 3rd metatarsals calcaneus

Question 27

Scaphoid Fracture overview

Answer 27

Most common carpal bone fracture. Typical age group is an adolescents and young adults (Grandma is more likely to get a distal radial fracture with a similar mechanism — fall). Blood flow is “retrograde” (distal to proximal). This is because the scaphoid surface is almost entirely (80%) covered with cartilage. As such, the proximal pole most susceptible to AVN and Non- Union. The first sign of AVN = Sclerosis (the dead bone can't turn over /recycle) Most common (70 %) fracture site = waist Displacement of > 1 mm will likely get a fixation screw to pull the fragments together. “Retrograde” (distal to proximal) via the Dorsal Carpal Branch of Radial Artery

Question 28

Scaphoid Fracture Trans-Scaphoid Perilunate Dislocation

Answer 28

60% association with a scaphoid fx

Question 29

Scaphoid Fracture Humpback deformity

Answer 29

This deformity results from angulation of the proximal and distal fragments - in the setting of a waist fracture. Can progress to progressive collapse and non-union. Associated with D1S1

Question 30

Scaphoid Fracture Scapholunate Ligament Disruption

Answer 30

Seen with 10-30% of distal radius and/or carpal fractures The SL ligament is composed of 3 parts (volar, dorsal, and middle), with the dorsal band being the most important for carpal stability (opposite o f luno triquetral which is volar). Disruption of the ligament predisposes for DISI deformity Gap >3 mm

Question 31

Scaphoid Fracture AVN

Answer 31

the proximal pole is at greatest risk. The first sign of AVN = Sclerosis (the adjacent bones will demineralize, but the avascular bone will not). Later the bone will fragment. MRI = T1 Dark Trivia: “Prieser Disease” is an atraumatic AVN of the scaphoid

Question 32

SLAC and SNAC Wrists Overview

Answer 32

Both are potential complications of trauma, with similar mechanisms. SLAC Wrist (Scaphoid-Lunate Advanced Collapse) occurs with injury (or degeneration via CPPD) to the S-L ligament. SNAC Wrist (Scaphoid Non-Union Advanced Collapse) occurs with a scaphoid fracture. Just remember that the scaphoid always wants to rotate in flexion - the scaphoid-lunate ligament is the only thing holding it back. If this ligament breaks it will tilt into flexion, messing up the dynamics of the wrist. The radial scaphoid space will narrow, and the capitate will migrate proximally.

Question 33

SLAC and SNAC wrists Treatment

Answer 33

depends on the occupation/needs of the wrist. Wrist fusion will maximize strength, but cause a loss of motion. Proximal row carpectomy will maximize ROM, but cause a loss of strength.

Question 34

SLAC and SNAC wrists trivia

Answer 34

* Radioscaphoid joint is first to develop degenerative changes * Capitate will migrate proximally and there will eventually be a DISI deformity

Question 35

Scapholunate Ligament Tear

Answer 35

The Terry Thomas look (gap between the scaphoid and lunate) on plain film. There are actually 3 parts (volar, dorsal, and middle), with the dorsal band being the most important for carpal stability. If they tear the carpals will migrate away from each other. Predisposed for DISI deformity

Question 36

DISI Vs VISI Overview

Answer 36

1 imagine two people (Lunate and Scaphoid) standing on opposite sides o f a very steep hill. At the apex o f the hill is a man named “Scapholunate Ligament” - 1 agree, it’s a strange name. His parents were probably vegetarians. This hill is very steep, so Scapholunate Ligament has grabbed each of the people (Lunate and Scaphoid) by the hand - he was worried they might fall. In fact, the only thing keeping these two people from tumbling down the hill is the insane grip strength o f Scapholunate Ligament (rumor has it he can close a #3 Captain o f Crush - which would certify him as an official Captain o f Crush). By using this analogy perhaps you can infer that if you have carpal ligament disruption, the carpal bones will rotate the way they naturally want to (down the hill). The reasons for their rotational desires are complex but basically have to do with the shape of the fossa they sit on. Just remember the scaphoid wants to flex (rock volar) and the lunate wants to extend (rock dorsal). The only thing holding them back is their ligamentous attachment to each other.

Question 37

DISI Dorsal Intercalated Segmental Instability Overview

Answer 37

1 like to call this dorsiflexion instability because it helps me remember what’s going on. After a “Radial sided injury” (scapholunate side), the lunate becomes free o f the stabilizing force o f the scaphoid and rocks dorsal ly. Remember SL ligament injury is common, so this is common.

Question 38

DISI Dorsal Intercalated Segmental Instability main

Answer 38

Widening of the SL angle - with dorsiflexion of the lunate. Angle greater than 60 degrees

Question 39

VISI (Volar Intercalated Segmental Instability) Overview

Answer 39

I like to call this volar-flexion (palmar-flexion) instability because it helps me remember what’s going on. After a “Ulnar sided injury” (lunotriquetral side), the lunate no longer has the stabilizing force of the lunotriquetral ligament and gets ripped volar with the scaphoid (remember the scaphoid stays up late every night dreaming o f tilting volar). Remember LT ligament injury is not common, so this is not common. It's so uncommon in fact that if you see it - it’s probably a normal variant due to wrist laxity.

Question 40

VISI (Volar Intercalated Segmental Instability) main

Answer 40

``` Narrowing of the SL angle - with volar-flexion of the lunate & scaphoid. Angle < 30 (this acute angle looks like a V to me - “V” for “V") ```

Question 41

Scapho-Lunate | Dissociation

Answer 41

sl wider than 3 mm clenched fist few can worsen it chronic sl dissocation can result in a slac wrist

Question 42

Peri-Lunate | Dislocation

Answer 42

the lunate stays put. its the carpal bones around the lunate that move 6-% are associated with scaphoid fxs

Question 43

Mid-Carpal | Dislocation

Answer 43

both lunate and capitate lose radial alignment associated with triquetro lunate interosseous ligament disruption associated with triquestral fracture

Question 44

Lunate dislocation

Answer 44

luante move easy, others stay it happens with a dorsal radiolunate ligament injury most severe

Question 45

Lunate dislocations lesser arc

Answer 45

Pure Ligament Injury (No | Fractures)

Question 46

Lunate dislocations greater arc

Answer 46

Associated with fractures. Described by saying “trans” the name of the fracture then the dislocation. Example “Trans-scaphoid, peri-lunate dislocation”

Question 47

Lunate dislocations space of poirier

Answer 47

``` Ligament free (“poor”) area, that is a site of weakness ```

Question 48

Which synovia l s p a c e s of the wrist n o rm a lly c om m u n ic a te ?

Answer 48

The answer is pisiform recess and radiocarpal joint. l can think o f two ways to ask this (1) related to fluid - the bottom line is that excessive fluid in the pisiform recess should not be considered abnormal if there is a radiocarpal effusion, and (2) that either space can be used for wrist arthrography.

Question 49

Glenohumeral Joint and | Subacromial Bursa

Answer 49

Should NOT communicate. Implies the presence o f a | full thickness rotator cuff tear.

Question 50

Ankle Joint and Common | (lateral) Peroneal Tendon Sheath

Answer 50

Should NOT communicate. Implies a tear o f the | calcaneofibular Ligament.

Question 51

Achilles Tendon and | Posterior Subtalar Joint

Answer 51

Should NOT communicate. The Achilles tendon | does NOT have a true tendon sheath.

Question 52

Pisifrom Recess and | Radiocarpal Joint

Answer 52

should normally communicate

Question 53

Triangular Fibrocartilage Complex — TFCC overview

Answer 53

I'll begin by saying that this is arguably the most complex anatomy in the entire body (maybe second only to the posterior lateral comer). A detailed understanding is well beyond the scope o f the exam (probably...). Having said that, the TFC is specifically mentioned on the official study guide, so we need to at least talk about it. The TFCC functions as the primary stabilizer and shock absorber o f the distal radial ulnar joint (DRUJ). The TFCC is critical for a range o f activities (doing a pushups , punching General Zod, e tc ...). It looks crazy complicated - but you really only need to know at most 5 structures, Of the 5, the Hand Surgeon only really gives a shit about the Articular Disc and Radioulnar Ligaments.

Question 54

Triangular Fibrocartilage Complex — TFCC mr signal

Answer 54

“TFC Proper” (Articular Disc) will be dark on every sequence. The ulnar attachment often looks intermediate in signal, this is normal related to loose connective tissue in the region. The radial attachment will also have intermediate signal, but this is from the normal articular cartilage.

Question 55

Triangular Fibrocartilage Complex — TFCC injuries

Answer 55

“Class 1” Acute Injuries: Usually via fall onto extended wrist. “Class 2” Chronic Degeneration: These are more common, and associated with positive ulnar variance and ulnar impaction. Central perforations are common - and might even be “expected” on an old person. Central Tear, with Ulnar Positive Variance and Abutment (cystic change in the lunate) -

Question 56

Triangular Fibrocartilage Complex — TFCC vasculature and healing

Answer 56

``` Similar to how the knee meniscus has “red” and “white” zones - the ulnar side o f the TFC is vascular and more likely to heal. Radial sided injuries are relatively avascular and less likely to heal. ```

Question 57

Triangular Fibrocartilage Complex — TFCC vasculature and healing

Answer 57

``` Similar to how the knee meniscus has “red” and “white” zones - the ulnar side o f the TFC is vascular and more likely to heal. Radial sided injuries are relatively avascular and less likely to heal. ```

Question 58

U ln a r V a r ia n c e overview

Answer 58

This is determined by comparing the lengths o f the ulna and distal radius. These length differences can occur congenitally, or be acquired from impaction / fracture deformity.

Question 59

U ln a r V a r ia n c e positive

Answer 59

Ulnar Impaction | Syndrome

Question 60

U ln a r V a r ia n c e negative

Answer 60

AVN o f the Lunate | “Kienbock”

Question 61

U ln a r Im p a c tio n Syndrome | (U ln a r A b u tm e n t):

Answer 61

Seen with positive ulnar variance. Essentially the distal ulna smashes into the lunate, degenerating it (cystic change / geodes e tc ...) and tears up the TFCC.

Question 62

Keinbocks

Answer 62

AVN o f the lunate, seen in people in their20s-40s. The most likely testable trivia is the association with negative ulnar variance. It’s going to show signal drop out on T1.

Question 63

Collies fracture

Answer 63

``` (Outward) "Collie Dogs ” Like it Outside Distal Metaphysis Fx Dorsal Angulation Old Lady Fracture Ulnar Styloid Fx is Commonly Associated ```

Question 64

Smith Fracture

Answer 64

``` (Inward) Distal Metaphysis Fx Volar Angulation Younger Patient Ulnar Styloid Fx is Commonly Associated ```

Question 65

Barton Fx

Answer 65

``` (Dorsal or Volar) Radial Rim Fx Volar is More Common Radial-Carpal Dislocation is the “hallmark” Typically Surgical (they have a high rate of re dislocation /mal-union) ```

Question 66

Radial Tilt

Answer 66

* There is a normal volar tilt o f around 11 degrees * With distal radial fractures this can get fucked up * Most Orthopods wo n ’t accept anything past neutral * A TRUE lateral is necessary to measure it How do yo u know yo u r lateral is “tru e " ? The volar cortex o f the pisiform overlies the central 1/3 o f the interval between the scaphoid and capitate

Question 67

Wrist tendon extensor compartments

Answer 67

There are 6 extensor compartments (5 fingers + 1 for good luck). First compartment (APL and EPB) are the ones affected in de Quervain’s Third compartment has the EPL which courses beside Lister’s Tubercle. The sixth compartment (Extensor Carpi Ulnaris) - can get an early tenosynovitis in rheumatoid arthritis.

Question 68

Carpal Tunnel overview

Answer 68

They could show you the carpal tunnel, but only to ask you about anatomy. What goes through the carpal tunnel (more easily asked as “what does NOT go through ”)? Knowing what is in (and not in) the carpal tunnel is high yield for multiple choice testing. The tunnel lies deep to the palmaris longus, and is defined by 4 bony prominences (pisiform, scaphoid tubercle, hook o f hamate, trapezium tubercle), with the transverse carpal ligament wrapping the contents in a fibrous sheath.

Question 69

Carpal Tunnel contents

Answer 69

* 4 Flexor D. Profudus (FDP) * 4 Flexor D. Superficials (FDS) * 1 Flexor Pollicis Longus (FPL), and * 1 Median Nerve

Question 70

Carpal Tunnel FCR

Answer 70

The Flexor Carpi Radialis (FCR) is NOT truly in the tunnel. The extensor tendons are on the other side o f the hand. Note that Flexor Pollicis Longus (FPL) goes through the tunnel, but Flexor Pollicis Brevis does not (it’s an intrinsic handle muscle). Palmaris longus (if you have one) does NOT go through the tunnel.

Question 71

Carpal Tunnel what does not go through it

Answer 71

-Flexor Carpi Radialis -Flexor Carpi Ulnaris -Palmaris Longus (if you have one) -Flexor Pollicis BREVIS

Question 72

Carpal Tunnel Syndrome

Answer 72

* Median Nerve Distribution (thumb-radial aspect o f 4th digit), often bilateral, and may have thenar muscle atrophy. * On Ultrasound, enlargement o f the nerve is the main thing to look for * It’s usually from repetitive trauma, * Trivia = Association with Dialysis. Pregnancy, DM, and HYPOthyroidism

Question 73

Carpal Tunnel syndrome classic findings

Answer 73

Classic Findings: • Increased Signal in the Median Nerve • The Nerve May Also Be Swollen or Look Smashed / Flattened • Bowing of the Flexor Retinaculum

Question 74

Guyon’s C an a l Syndrome

Answer 74

* Entrapment o f the ulnar nerve as it passes through Guyon’s canal (formed by the pisiform and the hamate - and the crap that connects them). * Classically caused by handle bars “handle bar p a lsy.” * Fracture o f the hook o f the hamate can also eat on that ulnar nerve.

Question 75

Sub-Sheath T e a r / D is lo c a tio n

Answer 75

This refers to a traumatic dislocation to the extensor carpi ulnaris (ECU - compartment 6) out o f its normal groove at the level o f the distal ulna. This dislocation / subluxation implies rupture o f the overlying sheath.

Question 76

Sub-Sheath T e a r / D is lo c a tio n trivia

Answer 76

the direction of the dislocation is medial

Question 77

Tuberculous or Nontuberculous Mycobacterial tenosynovitis

Answer 77

Hand and wrist are the most common tendons affected Diffuse exuberant tenosynovitis that spares the muscles. Usually occurs in patients who are immunocompromised. Discrete filling defects in the fluid filled sheaths (“rice bodies”) is a classic TB finding.

Question 78

RA Tenosynovitis

Answer 78

Multiple Flexor Tendons or Isolated Extensor Carpi Ulnaris if early (ECU = Compartment 6) Tenosynovitis can present as an early RA findings (before bone findings).

Question 79

Penetrating infection tenosynovitis

Answer 79

Tenosynovitis of any flexor tendon is a surgical emergency as it can spread rapidly to the common flexors of the wrist. Increased pressure in the sheath can cause necrosis of the tendons. Patients with delayed treatment tend to do terrible Myocobacterium Marinum is usually direct infection in a fisherman or sushi chef.

Question 80

Overuse Tenosynovitis

Answer 80

This is going to be classic | locations like 1 st extensor compartment for De Quervains — discussed more below.

Question 81

De Quervain’s Tenosynovitis:

Answer 81

So called “Washer Woman’s Sprain” or “Mommy Thumb.” Occurs from repetitive activity / overuse. The classic history is “new mom - holding a baby.” First Extensor Compartment (Extensor Pollicis Brevis and Abductor Pollicis Longus Finkelstein Test = Pain on passive ulnar deviation. The presence or absence of an intratendinous septum (between the EPB and APB) - tendons on the is a prognostic factor. If its absent, this will nearly always resolve with conservative treatment alone.

Question 82

De Quervain’s Tenosynovitis imaging

Answer 82

``` Ultrasound: Increased fluid within the first extensor tendon compartment MRI: increased T2 signal in the tendon sheath ```

Question 83

Intersection syndrome tenosynovitis

Answer 83

A repetitive use issue (classically seen in rowers), Occurs where the first extensor tendons, “intersects” the second extensor compartment tendons. The result is extensor carpi radialis brevis and longus tenosynovitis. Occurs 5 CM proximaly to listers tubercle

Question 84

Tenosynovitis overview

Answer 84

This is an inflammation of the tendon, with increased fluid seen around the tendon. This will be shown on MRI (or US).

Question 85

B en n e tt and Rolando | F ra c tu re s :

Answer 85

* They are both fractures at the base o f the first metacarpal * The Rolando fracture is comminuted (Bennett is not) * Trivia: The pull o f the Abductor Pollicis Longus

Question 86

G am e k e e p e r’s T h um b (S k ie r): overview

Answer 86

• Avulsion fracture at the base o f the proximal first phalanx associated with ulnar collateral ligament disruption. • The frequently tested association is that o f a “S te n e r Le s ion .” A Stener Lesion is when the Adductor tendon aponeurosis gets caught in the tom edges o f the UCL. The displaced ligament won’t heal right, and will need surgery. • It makes a “yo-yo” appearance on MRI - supposedly... • Next Step - Don’t do “ stress views” that can cause a stener. MRI is the more appropriate test.

Question 87

G am e k e e p e r’s T h um b (S k ie r): do not

Answer 87

DO NOT perform radiographic stress views for Gamekeepers Thumbs this will make it a stener

Question 88

G am e k e e p e r’s T h um b (S k ie r): stener lesion

Answer 88

Ulnar collateral ligament is retracted and | displaced superficial to the adductor aponeurosis.

Question 89

T rig g e r Finger:

Answer 89

The idea is the overuse / repetitive trauma causes scarring in the flexor tendon sheath. The fancy word is “stenosing tenosynovitis.” This is most commonly shown with ultrasound. If they should you a hand ultrasound think about this. Another common area o f “stenosing tenosynovitis” is at the ankle specifically the flexor hallucis longus tendon around the ankle in patients with the os trigonum syndrome.

Question 90

Elbow & Forearm General trivia

Answer 90

* Radial Head Fracture is most common in adults (supracondylar is most common in PEDs) * Sail sign - elevation o f the fat pads from a jo in t effusion. Supposedly a sign o f occult fracture. The testable trivia is (1) the posterior fat pad is more specific (posterior is positive), and (2) the posterior fat pad can appear falsely elevated (false positive) if the lateral isn’t a true 90 degree flexed lateral. "Posterior Positive, Posterior Position Dependent ” * Capitellum fractures are associated with posterior dislocation

Question 91

Fo re a rm F ra c tu re s / Eponyms Overivew

Answer 91

Forearm fractures are “ring” or “pretzel” type fractures, similar to the pelvis or mandible. Think about breaking a pretzel, it always snaps in two spots (not ju st one). So forearm fractures are often two fractures, or a fracture + dislocation.

Question 92

Fo re a rm F ra c tu re s / Eponyms monteggia fracture (MUGR)

Answer 92

Fracture of the proximal ulna, with anterior dislocation of the radial head. Dislocation of the radial head follows the angulation of the Ulnar Fx.

Question 93

Fo re a rm F ra c tu re s / Eponyms Galeazzi fracture (MUGR)

Answer 93

Radial shaft fracture, with anterior | dislocation of the ulna at the DRUJ.

Question 94

Essex lopresti

Answer 94

Fracture of the radial head + Anterior dislocation of the distal radial ulnar joint. Unstable fracture - With rupture of the interosseous membrane

Question 95

C u b ita l Tu nne l Syndrome overview

Answer 95

There are several causes - the most common in the real world is probably repetitive valgus stress. The most common shown on multiple choice is probably an accessory anconeus. WTF is an “Anconeus ” ? It a piece o f shit muscle that does nothing but get in the way o f an orthopedic scope. It’s normally on the lateral side the elbow. You can have an “Accessory Anconeus ” - also called an “Anconeus Epitrochlearis ’’ - on the medial side which will exert mass effect on the ulnar nerve.

Question 96

C u b ita l Tu nne l Syndrome anatomy trivia

Answer 96

The site where the ulnar nerve passes beneath the cubital tunnel retinaculum also known as the epicondylo-olecranon ligament or Osborne’s ligament.

Question 97

L a te ra l E p ico n d y litis

Answer 97

(more common than medial) - seen in Tennis Players - • Extensor Tendon Injury (classically extensor carpi radialis brevis) • Radial Collateral Ligament Complex - Tears due to varus stress

Question 98

M ed ia l E p ico n d y litis

Answer 98

(less common than lateral) - seen in golfers | • Common flexor tendon and ulnar nerve may enlarge from chronic injury

Question 99

P a r tia l U ln a r C o lla te ra l L ig am e n t T e a r:

Answer 99

For the exam all you really need to know is that throwers (people who valgus overload) hurt their ulnar collateral ligament (which attaches on the medial coronoid - sublimetubercle). The ligament has three bundles, and the anterior bundle is by far the most important. If you get any images it is most likely going to be of the partial UCL tear, described as the “T sign,” with contrast material extending medial to the tubercle

Question 100

L ittle L e a g u e r E lb ow

Answer 100

The children of insecure men who sucked at sports in high school are most susceptible to this injury. The mechanism is repetitive micro-trauma from endless hours of training (necessary to finally rectify the injustice which beset their family when dad was benched senior year from the junior varsity baseball squad). ``` We are talking about a repetitive chronic injury to the medial epicondyle. When I say injury I mean stress fracture, avulsion, or delayed closure of the medial epicondvlar apophysis. This is usually associated with UCL injury. ``` ``` Children aren’t the only ones who can fuck up their elbows pursuing the kind of immortality that is only offered to those worthy enough to step foot on the field at Yankee stadium. There is a well described “valgus overload syndrome” seen in throwers, consisting of a triad of lateral compression, medial tension, and posterior sheer. This mechanism results in UCL injury (often anterior band), Arthritis at the Posterior Humerus / Ulna, and the development of an OCD at the capitellum. ```

Question 101

Epitrochlear lymphadenopathy

Answer 101

ct scratch disease

Question 102

Dialysis elbow

Answer 102

This is the result of olecranon bursitis from constant pressure on the area, related to positioning of the arm during treatment.

Question 103

Biceps Tear overview

Answer 103

Tears can be partial or complete. When complete the tear typically occurs in shoulder with the tendon avulsing off the labrum (or at the level of the bicipital groove). Common mechanism is incorrect deadlift form (while doing cross fit like an ape on cocaine). If you plan on going nuts slinging that shit around consider switching to a double over grip. If you want to use over under grips - you need strict form (keep your arms locked out dummy). There are tons of highlight reals on youtube of people tearing biceps while deadlifting - notice every single one is using an over under grip, and not maintaining straight arm technique.

Question 104

PArtial Biceps Tear gamesmanship

Answer 104

Partial tears often arc associated with bicipitoradial bursitis

Question 105

Biceps Tear gamesmanship

Answer 105

Injury to the bicep is associated with median nerve symptoms

Question 106

Tricep rupture

Answer 106

The tricep tendon has the honorable distinction of being the LEAST common tendon in the body to rupture. Even tendinopathy is fairly uncommon relative to other nearby structures. When it does tear you should be thinking about salter harris II fractures of the olecranon - that is the classic scenario. 1 think because this is so uncommon that mimics would be more likely on the exam. So, I’d be aware of two things: (1) the normal striated appearance of the insertion at the olecranon, and (2) the common entity of olecranon bursitis - which you should think of first if you see a bunch of fluid signal in the posterior elbow.

Question 107

Elbow dislocation overview

Answer 107

This is the second most common joint dislocated in the adult. The associated fractures are usually the radial head and the coronoid process. Instability in the elbow (so called P o s te rio r R o ta ry In s ta b ility ) is described in a pattern starting in the posterior lateral comer with tearing o f the lateral UCL.

Question 108

elbow dislocation steps

Answer 108

Tearing of the LUCL (lateral UCL). Partial Dislocation Coronoid Perched on Trochlea (LUCL + LCL + Capsule) Dislocation Coronoid Posterior to Humerus with a UCL Tear

Question 109

Anterior Shoulder dislocation

Answer 109

Anterior inferior (subcoracoid) are by far the most common (like 90%). o Hill-Sachs is on the Humerus. o Hill-Sachs is on the posterior lateral humerus, and best seen on internal rotation view. O Bankart - anterior inferior labrum O Greater tuberosity avulsion fracture occurs in 10-15% o f anterior dislocations in patient’s over 40.

Question 110

Posterior shoulder dislocation

Answer 110

Posterior Dislocation: uncommon - probably from seizure or electrocution O Rim Sign - no overlap glenoid and humeral head O Trough Sign - reverse Hill Sachs, impaction on anterior humerus O “Light Bulb Sign ” - Arm may be locked in internal rotation on all views

Question 111

Inferior dislocation

Answer 111

(lu.xatio erecta humeri) - this is an uncommon form, where the arm is sticking straight over the head. The thing to know is 60% get neurologic injury (usually the axillary nerve).

Question 112

Hill-Sachs

Answer 112

Posterolateral humeral head impaction fracture (anterior dislocation)

Question 113

Bankart

Answer 113

Anterior Glenoid Rim | anterior dislocation

Question 114

Trough Sign

Answer 114

Anterior humeral head impaction | fracture (posterior dislocation)

Question 115

Reverse Bankart

Answer 115

Posterior Glenoid Rim | posterior dislocation

Question 116

Dislocation memory tool

Answer 116

1 remember that hip dislocations are posterior - from the straight leg dashboard mechanism. Then I ju st remember that shoulders are the opposite o f that (the other one, is the other one). Shoulder = Usually Anterior

Question 117

Proximal humerus fx

Answer 117

This is usually in an old lady falling on an out stretched arm. Orthopods use the Neer classifications (how many parts the humerus is in ?). Three or four part fractures tend to do worse.

Question 118

T h e Post Op S h o u ld e r (P ro s th e s is ) 4 main types

Answer 118

Humeral Head Resurfacing, Hemi Arthroplasty, Total Shoulder Arthroplasty, and the Reverse Total Shoulder Arthroplasty.

Question 119

T h e Post Op S h o u ld e r (P ro s th e s is ) reverse total shoulder

Answer 119

A conventional total shoulder mimics normal anatomy. A reserve total shoulder is the bizarro version; with a plastic cup on the humeral head and metallic sphere on the glenoid.

Question 120

T h e Post Op S h o u ld e r (P ro s th e s is ) who gets what

Answer 120

glenoid and cuff intact - resurfacing or hemi glenoid intact and cuff deficient - hemi or reverse glenoid deficient cuff intact - TSA Glenoid deficient and cuff deficient - reverse

Question 121

T h e Post Op S h o u ld e r (P ro s th e s is ) complications/trivia

Answer 121

—Total Shoulder Most Common Complication = Loosening o f the Glenoid Component —Total Shoulder Complication - “Anterior Escape ” - This describes anterior migration o f the humeral head after subscapularis failure. — Reverse Total Shoulder Does NOT require an intact rotator cuff - patient rely heavily on the deltoid. — Reverse Shoulder Complication - Posterior Acromion Fracture - from excessive deltoid tugging.

Question 122

Impingement / Rotator Cuff Tears overview

Answer 122

This is a high yield / confusing subject that is worth talking about in a little more detail. In general, rotator cuff pathology is the result o f overuse activity (sports) or impingement mechanisms. There are two types o f impingement with two major sub-divisions within those types. Like many things in Radiology, if you get the vocabulary down, the pathology is easy to understand.

Question 123

Impingement / Rotator Cuff Tears extranal overview

Answer 123

This refers to impingement o f the rotator cuff overlying the bursal surfaces (superficial surfaces) that are adjacent to the coracoacromial arch. As a reminder, the arch is made up o f the coracoid process, acromion, and coracoacromial ligament.

Question 124

Impingement / Rotator Cuff Tears external primary causes

Answer 124

(Abnormal Coracoacromial Arch) : • The hooked acromion (type III Bigliani) is more associated with external impingement than the curved or flat types. • Subacromial osteophyte formation or thickening o f the coracoacromial ligament • Subcoracoid impingement: Impingement o f the subscapularis between the coracoid process and lesser tuberosity. This can be secondary to congenital configuration, or a configuration developed post traumatically after fracture o f the coracoid or lesser tuberosity.

Question 125

Impingement / Rotator Cuff Tears external secondary causes

Answer 125

(Normal Coracoacromial Arch): • “Multidirectional Glenohumeral Instability” - resulting in micro-subluxation o f the humeral head in the glenoid, resulting in repeated micro-trauma. The important thing to know is this is typically seen in patients with generalized jo in t laxity, often involving both shoulders.

Question 126

Impingement / Rotator Cuff Tears internal overview

Answer 126

This refers to impingement o f the rotator cuff on the undersurface (deep surface) along the glenoid labrum and humeral head.

Question 127

Impingement / Rotator Cuff Tears internal posterior superior

Answer 127

This is a type o f impingement that occurs when the posterior superior rotator cuff (junction o f the supra and infraspinatus tendons) comes into contact with the posterior superior glenoid. Best seen in the ABER position, where these tendons get pinched between the labrum and greater tuberosity. This is seen in athletes who make overhead movements (throwers, tennis, swimming).

Question 128

Impingement / Rotator Cuff Tears internal anterior superior

Answer 128

This is internal impingement that occurs when the ann is in horizontal adduction and internal rotation. In this position, the undersurface o f the biceps and subscapularis tendon may impinge against the anterior superior glenoid rim.

Question 129

External impingement primary quick

Answer 129

``` ’ Abnormal Coracoacromial Arch — Hook Shaped (B3) — Osteophytes —Post Traumatic — Thickened Ligaments ``` Subacromial - F's with a supra S Subacoracoid - F's with Sub S

Question 130

External impingement secondary quick

Answer 130

Multidirectional Instability — Labrum Often Normal —“Increased Glenohumeral Volume” - with injection

Question 131

Internal impingement posterior superior quick

Answer 131

’Throwers — F’s with Infraspinatus (and posterior Supra) —Posterior Superior Labrum Torn —Cystic Change in Greater Tuberosity

Question 132

Internal impingement anterior superior quick

Answer 132

—Associated with Sub Scapular damage (Maybe the cause rather than the result) —Anterior Superior Labrum Torn

Question 133

High Yield Trivia Points on Impingement subacromial impingement

Answer 133

most common form, resulting from attrition o f the coracoacromial arch. Damages Supraspinatus Tendon.

Question 134

High Yield Trivia Points on Impingement subcoracoid impingement

Answer 134

Lesser tuberosity and coracoid do the pinching. Damages Subscapularis (remember the coracoid is anterior - an d so is the subscapularis).

Question 135

High Yield Trivia Points on Impingement posterior superior "internal" impingment

Answer 135

-A th le te s who make overhead movements. Greater tuberosity and posterior inferior labrum do the pinching. Damages Infraspinatus (and posterior fibers o f the supraspinatus).

Question 136

Rotator Cuff Tears overview

Answer 136

People talk about these tears as either “Bursal Sided” (meaning the top part), or “Articular Sided” (meaning the undersurface). A tear o f the articular surface is more common (3x more) than the bursal surface. The underlying mechanism is usually degenerative, although trauma can certainly play a role.

Question 137

Rotator Cuff Tears most common of the 4 muscles

Answer 137

Supraspinatus - with most tears occurring at the " c r itic a lzo n e” - 1-2 cm from the tendon footprint. This relatively avascular “critical zone” is also the most common location for Calcium Hydroxyapatite (HADD) - or “calcific tendinitis.” The Teres Minor is the least common to tear.

Question 138

Rotator Cuff Tears partial tear

Answer 138

A partial tear that is > 50% often results in a surgical intervention.

Question 139

Rotator Cuff Tears massive rotator cuff tear

Answer 139

refers to at least 2 out o f the 4 rotator cuff muscles

Question 140

Rotator Cuff Tears general piece of trivia

Answer 140

A final general piece o f trivia is that a tear o f the fibrous rotator cuff interval (junction between anterior fibers o f the Supraspinatus and superior fibers o f the subscapularis), is still considered a rotator cuff tear.

Question 141

Rotator Cuff Tears How do you know it is a full thickness tear?

Answer 141

You will have high T2 signal in the expected location o f the tendon. On T1 you will have Gad in the bursa.

Question 142

Adhesive Capsulitis “Frozen Shoulder” overview

Answer 142

An inflammatory condition characterized by a global decrease in motion. You can have primary types, but a multiple choice key would be a history o f trauma or surgery. It most commonly effects the rotator cu ff interval - and that is the most likely spot they will show it. The classic look is a T1 (or non-fat sat T2) in the sagittal plane showing loss o f fa t in the rotator c a ff interval (the spot with the biceps tendon - between the Supra S,and the Sub Scap).

Question 143

Adhesive Capsulitis “Frozen Shoulder” buzz1

Answer 143

‘Decreased Glenohumeral Volume ” - with injection

Question 144

Adhesive Capsulitis “Frozen Shoulder” buzz2

Answer 144

** Remember in Multi-Directional Instability the volume was increased.

Question 145

Adhesive Capsulitis “Frozen Shoulder” buzz3

Answer 145

"Thickened inferior a n d Posterior Capsule ”

Question 146

Adhesive Capsulitis “Frozen Shoulder” buzz4

Answer 146

"Enhancement o f the Rotator C u ff Interval - Post gad

Question 147

SLAP overview

Answer 147

Labral tears favor the superior margin and track anterior to posterior. As this tear involves the labrum at the insertion o f the long head o f the biceps , injury to this tendon is associated and part o f the grading system (type 4).

Question 148

SLAP things to know

Answer 148

When the SLAP extends into the biceps anchor (type 4), the surgical management changes from a debridement to a debridement + biceps tenodesis. The mechanism is usually an over-head movement (classic = swimmer) People over 40 usually have associated Rotator Cuff Tears NOT associated with Instab ility (usually)

Question 149

SLAP mimic 1

Answer 149

The sublabral recess This is essentially a normal variant where you have incomplete attachment o f the labrum at 12 o'clock. The 12 o'clock position on the labrum has the shittiest blood flow - that's why you see injury there and all these developmentvariants.

Question 150

SLAP mimic 2

Answer 150

The Sublabral Foramen - This is an unattached (but present) portion o f the labrum - located at the anterior-superior labrum (1 o'clock to 3 o ’clock). As a rule it should NOT extend below the equator (3 o'clock position).

Question 151

SLAP mimic 3

Answer 151

The Buford Complex - A commonly tested (and not infrequently seen) variant is the Buford Complex. It’s present in about 1% o f the general population. This consists o f an absent anterior/superior labrum (1 o'clock to 3 o ’clock), along with a thickened middle glenohumeral ligament.

Question 152

Buford complex

Answer 152

- Thick Middle GH Ligament | - Absent Anterior Superior Labrum

Question 153

sublabral recess

Answer 153

Follows contour of glenoid smooth margin located at biceps anchor

Question 154

B a n k a r t L e s io n s list

Answer 154

Anterior dislocation injuries ``` GLAD Perthes ALPSA Bankart - cartilaginous Bankart (Osseous) ```

Question 155

GLAD

Answer 155

Glenolabral Articular Disruption. It’s the most mild version, and it’s basically a superficial anterior inferior labral tear with associated articular cartilage damage (“ impaction injury with cartilage defect”). Not typically seen in patients with underlying laxity. It’s common in sports. No instability (a ren'tyou GLAD there is no instability)

Question 156

Perthes

Answer 156

Detachment o f the anteroinferior labrum (3-6 o'clock) with medially stripped looks but intact periosteum. Memory Aid: -The detached labrum sorta like a P

Question 157

ALPSA

Answer 157

Anterior Labral Periosteal Sleeve Avulsion. Medially displaced labroligamentous complex with absence o f the labrum on the glenoid rim. Intact periosteum. It scars down to glenoid.

Question 158

True bankart

Answer 158

Can be cartilaginous or osseous. The periosteum is disrupted. There is often an associated Hill Sach’s fracture.

Question 159

GLAD quick

Answer 159

superficial partial labral injury no instability

Question 160

Perthes quick

Answer 160

Avulsed anterior labrum (only minimally displaced) inferior GH complex still attached to periosteum intact periosteum (lifted up)

Question 161

ALPSA quick

Answer 161

similar to perthes but with bunhced up and medially displaced inferior GH complex

Question 162

True bankart quick

Answer 162

torn labrum periosteum disruption

Question 163

P o s te rio r G len o h um e ra l In s ta b ility overview

Answer 163

As I mentioned previously, anterior shoulder dislocations are way more common than posterior shoulder dislocations. Therefore the Bankart, ALPSA, Perthes, e tc ... are the ones you typically think o f as the stigmata o f prior dislocation. However, all that shit can happen in reverse with a posterior dislocation.

Question 164

P o s te rio r G len o h um e ra l In s ta b ility list

Answer 164

reverse osseous bankart polpsa bennett lesion kims lesion

Question 165

Reverse osseous bankart

Answer 165

A fracture o f the posterior inferior | rim o f the glenoid.

Question 166

POLPSA

Answer 166

This is the bizarro version o f the ALPSA, where the posterior labrum and the posterior scapular periosteum (still intact) are stripped from the glenoid resulting in a recess that communicates with the joint space.

Question 167

Bennett lesion

Answer 167

An extra-articular curvilinear calcification - associated with posterior labral tears tmavbe the POLPSA). It’s related to injury o f the posterior band o f the inferior glenohumeral ligament.

Question 168

Kims lesion

Answer 168

An incompletely avulsed / flattened / mashed posteriorinferior labrum. A key (testable) point is the glenoid cartilage and posterior labrum relationship is preserved.

Question 169

HAGL

Answer 169

A non-Bankart lesion that is frequently tested is the HAGL (Humeral avulsion glenohumeral ligament). This is an avulsion o f the inferior glenohumeral ligament, and is most often the result o f an anterior shoulder dislocation (just like all the above bankarts). The “J Sign” occurs when the normal U-shaped inferior glenohumeral recess is retracted away from the humerus, appearing as a J.

Question 170

S u b lu x a tio n o f th e B ic ep s Tendon overview

Answer 170

The subscapularis attaches to the lesser tuberosity. It sends a few fibers across the bicipital groove to the greater tuberosity , which is called the “transverse ligament”. A tear o f the subscapularis opens these fibers up and allows the biceps to dislocate (usually medial). Subscapularis Tear = Medial Dislocation of the Long Head of the Biceps Tendon.

Question 171

S u b lu x a tio n o f th e B ic ep s Tendon subscap tendon

Answer 171

Forming portions of the "Transverse Ligament" that holds the biceps tendon in the groove

Question 172

S u b lu x a tio n o f th e B ic ep s Tendon quick

Answer 172

Occurs with a Tear of the Subscapularis

Question 173

S u p ra s c a p u la r N o tch vs Sp in o g len o id N o tch

Answer 173

A cyst at the level o f the suprascapular notch will affect the supraspinatus and the infraspinatus. At the level o f the spinoglenoid notch, it will only affect the infraspinatus.

Question 174

Q u a d rila te ra l S p a c e Syndrome

Answer 174

Compression o f the Axillary Nerve in the Quadrilateral Space (usually from fibrotic bands). They will likely show this with atrophy of the teres minor. Another classic question is to name the borders o f the quadrilateral space: Teres Minor Above, Teres Major Below, Humeral neck lateral, and Triceps medial.

Question 175

P a rso n a g e -T u rn e r Syndrome

Answer 175

This is an idiopathic involvement o f the brachial plexus. Think about this when you see muscles affected by pathology in two or more nerve distributions (suprascapular and axillary etc..).

Question 176

Fem ora l S h a ft F ra c tu re s medial side

Answer 176

On the inside (medial) is the classic stress fracture location

Question 177

Fem ora l S h a ft F ra c tu re s lateral side

Answer 177

On the outside (lateral) is the classic bisphosphonate related fx location. As shown in the image, you see cortical thickening (white arrow) along the lateral femur, eventually progressing into a fracture.

Question 178

Hip fracture/dislocation overview

Answer 178

You see these with dash board injuries. The posterior dislocation (almost always associated with a fracture as it’s driven backwards) is much more common than the anterior dislocation.

Question 179

Hip fracture/dislocation iliopectineal line

Answer 179

anterior

Question 180

Hip fracture/dislocation anterio column vs posterior column

Answer 180

The both column fracture by definition divides the ilium proximal to the hip joint, so you have no articular surface o f the hip attached to the axial skeleton (that’s a problem).

Question 181

Hip fracture/dislocation hip fx leading to avn

Answer 181

The location o f the fracture may predispose to AVN. It’s important to remember that, since the femoral head gets vascular flow from the circumflex femorals, a displaced intracapsular fracture could disrupt this blood supply - leading to AVN. Testable Point: Degree o f fracture displacement corresponds with risk o f AVN.

Question 182

Hip fracture/dislocation corona mortis

Answer 182

The anastomosis o f the inferior epigastric and obturator vessels sometimes rides on the superior pubic ramus. During a lateral dissection - sometimes used to repair a hip fracture - this can be injured. 1 talk about this more in the vascular chapter.

Question 183

Hip fracture/dislocation hip fx leading to avn

Answer 183

The location o f the fracture may predispose to AVN. It’s important to remember that, since the femoral head gets vascular flow from the circumflex femorals, a displaced intracapsular fracture could disrupt this blood supply - leading to AVN. Testable Point: Degree o f fracture displacement corresponds with risk o f AVN.

Question 184

Avulsion In jury : Hip overview

Answer 184

This is seen more in kids than adults. Adult bones are stronger than their tendons. In kids it’s the other way around. One pearl is that if you see an isolated “ avulsion” of the lesser trochanter in a seemingly mild trauma / injury in an adult - query a pathologic fracture. Now, to discuss what 1 believe to be one o f the highest yield topics in MSK, “where d id the avulsion come from? ” The easiest way to show this is a plain film pelvis (or MRI) with a tug/avulsion injury to one o f the muscular attachment sites. The question will most likely be "what attaches there? ” or “which muscle got avulsed? ”

Question 185

Muscle that originates iliac crest

Answer 185

abdominal muscles

Question 186

Muscle that originates asis

Answer 186

sartorius TFL

Question 187

Muscle that originates AIIS

Answer 187

rectus femoris

Question 188

Muscle that originates greater trochanter

Answer 188

Gluteal muscles

Question 189

Muscle that originates lesser trochanter

Answer 189

iliopsoas

Question 190

Muscle that originates ischial tuberosity

Answer 190

hamstrings

Question 191

Muscle that originates pubic symphysis

Answer 191

adductor group

Question 192

Snapping Hip Syndrome steps

Answer 192

Clinical Eval for the “E x tern a l Type” (IT band “snapping” over the Greater Trochanter) This is to evaluate for the “In tra-Articular Type” Looking for Hip Degen / Loose Bodies, Etc Radiographs? IF NO Degen NEXT S T EP = Ultrasound This is to look for the “In te rn a l Type” Look for Dynamic “Snapping” o f the Iliopsoas over the Uiopectineal eminence or femoral head *This has to he shown with a CINE - because the finding is a dynamic moving o f a tendon I f yo u see a hip ultrasound fo r snapping - this is what they are going fo r IF US Negative NEXT S T EP = MRI Arthrogram This is to evaluate for the “Intra-Articular Type" ... Again This time looking for Labral Tears

Question 193

Snapping Hip Syndrome trivia

Answer 193

clinical sensation they have to tell you the pt feels snapping

Question 194

Snapping Hip Syndrome types

Answer 194

* External (most common) = Iliotibial Band over Greater Trochanter * Internal = Iliopsoas over Uiopectineal eminence or femoral head * Intra-Articular = Labral tears / jo in t bodies

Question 195

Snapping Hip Syndrome types

Answer 195

* External (most common) = Iliotibial Band over Greater Trochanter * Internal = Iliopsoas over Uiopectineal eminence or femoral head * Intra-Articular = Labral tears / jo in t bodies

Question 196

IT Band Syndrome

Answer 196

This is a repetitive stress syndrome seen most classically in runners. The key finding is fluid on both sides of the IT band, extending posterior and lateral. Fluid in the joint does not exclude the diagnosis, but for the purpose of multiple choice if you see fluid around the band and none in the joint you can be fairly certain this is the pathology the question writer is after.

Question 197

Hip Labrum what to know

Answer 197

1: Anterior-Superior Tears (white arrows) are by far the most common. 2: Paralabral Cysts (black arrow) are associated with tears and likely a hint that a tear is present. 3: Just like a shoulder intra-articular contrast will increase your sensitivity.

Question 198

Ilio p so a s Bursa overview

Answer 198

* Largest bursa o f the entire body. * Communicates with the joint in 15% o f the population * Seen Anterior to the hip * Trivia: The illiospsoas tendon runs anterior to the labrum on axial and can mimic a tear.

Question 199

Ilio p so a s Bursa gamesmanship

Answer 199

A fluid signal “mass” with anterior to the femur (adjacent to the psoas tendon) at the level of the ischial tuberosity is likely Iliopsoas Bursitis

Question 200

F em o ro a c e ta b u la r Im p in g em e n t (FAI): overview

Answer 200

This is a syndrome of painful hip movement. It’s based on hip / femoral deformities, and honestly might be total BS. Supposedly it can lead to early degenerative changes. There arc two described subtypes: (A) Cam and (B) Pincher (technically there is a mixed type - but I anticipate multiple choice to make it more black and white).

Question 201

F em o ro a c e ta b u la r Im p in g em e n t (FAI): memory aid

Answer 201

I remember that the femoral one (cam-type) is more common in men because the femoral head kinda looks like a penis. Be honest, you were thinking that too.

Question 202

F em o ro a c e ta b u la r Im p in g em e n t (FAI): cam type

Answer 202

This is an osseous “bump” along the femoral head-neck junction.

Question 203

F em o ro a c e ta b u la r Im p in g em e n t (FAI): pincer type

Answer 203

Whereas the CAM type is a deformity of the femur, the pincer type represents a deformity of the acetabulum. Whereas the CAM type is more common in a young athletic male, the pincer is more common in a middle aged woman (insert sexist joke here).

Question 204

F em o ro a c e ta b u la r Im p in g em e n t (FAI): coxa profunda

Answer 204

acetabulu projects medial to the ilioschial line

Question 205

F em o ro a c e ta b u la r Im p in g em e n t (FAI): acetabular protrusion

Answer 205

Femur projects medial to the ilioischial line

Question 206

F em o ro a c e ta b u la r Im p in g em e n t (FAI): os acetabuli

Answer 206

This is an unfused secondary >=> ossification center. It’s actually normal in kids (should fuse by adult hood). It has several testable associations including FAI and Labral Tears

Question 207

FAI classic way to ask

Answer 207

The most classic way to show or ask this is the so-called “cross over sign”, where the acetabulum is malformed - causing the posterior lip to “Cross over” the anterior lip. A Key point is that the coccyx needs to be centered at the symphysis pubis to even evaluate this (rotation fucks things up). The other associated finding) s) of the pincer subtype worth knowing are the acetabular over coverage buzzwords (Coxa Profunda and Protrusio), and the Ischial Spine Sign:

Question 208

Total Hip Arthroplasty bone remodeling/stress shielding

Answer 208

The stress is transferred through the metallic stem, so the bone around it is not loaded. Orthopods call this “Wolff’s Law’ - where the unloaded bone just gets resorbed. Happens more with uncemented arthroplasty. To some degree this is a normal finding - but when advanced can predispose to fracture.

Question 209

Total Hip Arthroplasty asymptomatic complications

Answer 209

* Stress Shielding | * Aggressive Granulomatosis

Question 210

Total Hip Arthroplasty proximal stress shielding

Answer 210

Proximal stress shielding -greater trochanter bone resorption

Question 211

Total Hip Arthroplasty distal stress loading

Answer 211

Distal stress loading: cortical thickening & pedestral (around the bottom) “Zone 4“

Question 212

Total Hip Arthroplasty heterotopic ossifications

Answer 212

This is very common (15-50%). It’s usually asymptomatic. The trivia regarding multiple choice tests is that “hip stiffness” is the most common complaint. Also in Ank Spon patients, because they are so prone to heterotopic ossifications, they sometimes give them low dose prophylactic radiation prior to THA.

Question 213

Total Hip Arthroplasty aseptic loosening

Answer 213

This is the most common indication for revision. The criteria on x-ray is > 2 mm at the interface (suggestive). If you see migration of the component, you can call it (migration includes varus tilting o f the femora! stem).

Question 214

Total Hip Arthroplasty subsidence

Answer 214

Basically an arthroplasty that is sliding downward. This is a described reason for early failure of THA. You see this most often in arthroplasty implants without a collar. Greater than 1 cm along the femoral component, or progression after 2 years are indications of loosening.

Question 215

Total Hip Arthroplasty wear patterns

Answer 215

It is normal to have a little bit of thinning in the area of weight bearing - this is called “Creep.” It is not normal to see wear along the superior lateral aspect. • Wear = Pathologic • Creep = Normal

Question 216

Total Hip Arthroplasty particle diseaase

Answer 216

(Aggressive Granulomatosis): Any component of the device that sheds will cause an inflammatory response. The more wear that occurs the more particles — wear is the primary underlying factor. Macrophages will try and eat the particles and spew enzymes all over the place. This process can cause progressive lytic focal regions around the replacement and joint effusions.

Question 217

Total Hip Arthroplasty things to know about particle disease

Answer 217

Most commonly seen in non-cementcd hips Tends to occur 1 -5 years after surgery — “late complication” X-ray shows “smooth” endosteal scalloping (distinguishes from infection) Aseptic - ESR & CRP will be normal Produces no secondary bone response — no sclerosis Can be seen around screw holes (particles are transmitted around screws)

Question 218

Total Hip Arthroplasty particle disease steps

Answer 218

wear > particle disease > osteolysis

Question 219

Sacrum overview

Answer 219

You can get fractures o f the sacrum in the setting o f trauma, but if you get shown or asked anything about the sacrum it’s going to be either (a) SI degenerative change - discussed later, (b) unilateral SI infection, (c) a chordoma - discussed later, (d) sacral agenesis, or (e) an insufficiency fracture. Out o f these 5 things, the insufficiency fracture is probably the most likely.

Question 220

Sacrum insuffieciency fx

Answer 220

The most common cause is postmenopausal osteoporosis. You can also see this in patients with renal failure, patients with RA, pelvic radiation, mechanical changes after hip arthroplasty, or extended steroid use. They are often (usually) occult on plain films.

Question 221

Sacrum insufficiency fx imaging

Answer 221

They will have to show this either with a bone V scan, or MRI. The classic “Honda Sign” from the “H” -shaped appearance is probably the most likely presentation on a mult,pie choice test.

Question 222

Segond F ra c tu re :

Answer 222

This is a fracture o f the Lateral Tibial Plateau (icommon distractor is medial tibia). The thing to know is that it is associated with ACL tear (75%), and occurs with internal rotation.

Question 223

reverse segond fx

Answer 223

This is a fracture of the Medial Tibial Plateau. The thing to know is that it is associated with a PCL tear, and occurs with external rotation. There is also an associated medial meniscus injury.

Question 224

arcuate sign

Answer 224

This is an avulsion o f proximal fibula (insertion of arcuate ligament complex). The thing to know is that 90% are associated with cruciate ligament injury (usually PCL)

Question 225

deep intercondular notch sign

Answer 225

This is a depression of the lateral femoral condyle (terminal sulcus) that occurs secondary to an impaction injury. This is associated with ACL tears.

Question 226

ACL anatomy

Answer 226

Composed of two bundles (anteromedial & posterolateral). The tibial attachment is thicker then the femoral attachment. Both the ACL and PCL are intra-articular and extrasynovial.

Question 227

PCL anatomy

Answer 227

The strongest ligament in the knee (you don’t want a posterior dislocation of your knee resulting in dissection of your popliteal artery).

Question 228

MCL anatomy

Answer 228

The MCL fibers arc laced into the joint capsule at the level of the joint, with connection to the medial meniscus. Unlike the ACL and PCL, the MCL is an extra-articular structure.

Question 229

Conjoint tendon anatomy

Answer 229

Formed by the biceps femoris | tendon and the LCL.

Question 230

ACL and PCL overview

Answer 230

``` ACL & PCL are extrasynovial and intraarticular. The synovium folds around the ligaments. This is why a tom ACL won’t heal on its own (usually). The ligament can be tom even if the synovium is intact - this is why the “taunt” angle of the ligament is a key feature of integrity - more on that later ```

Question 231

IT band inserts on

Answer 231

Gerdys tubercle

Question 232

M a g ic A n g le Phenomeno n

Answer 232

The PCL and Patellar tendon may have foci o f intermediate signal intensity on sagittal images with short echo time (TE) sequences where the tendon forms an angle o f 55 degrees with the main magnetic field (magic angle p h en omen o n ). This will NOT be seen on T2 sequences (with long TE). This phenomenon is reduced at higher field strengths due to greater shortening o f T2 relaxation times.

Question 233

M a g ic A n g le Phenomeno n quick

Answer 233

You sec it on short TE sequences (Tl, PD, GRE). It goes away on T2

Question 234

ACL T e a r: overview

Answer 234

* Associated with Segond Fracture (lateral tibial plateau) and tibial spine avulsion * ACL Angle lesser than Blumensaat’s Line * O’donoghue’s Unhappy Triad: ACL Tear, MCL Tear, Medial Meniscal Tear * Classic Kissing Contusion Pattern: The lateral femoral condyle (sulcus terminals) bangs into the posterior lateral tibial plateau. This is 95% specific in adults. * Anterior Drawer Sign = Ortho Physical Exam Finding suggesting ACL Tear.

Question 235

ACL Mucoid D e g e n e ra tio n

Answer 235

This can mimic acute or chronic partial tear of the ACL. There will be no secondary signs of injury (contusion etc..). It predisposes to ACL ganglion cysts, and they are usually seen together. The T2/STIR buzzword is “celery stalk” because o f the striated look. T h eT l buzzword is “drumstick” because it looks like a drum stick.

Question 236

ACL repair

Answer 236

ACL can be repaired with two primary methods. Method 1: Using the middle one-third of the patellar tendon, with the patella bone plug attached to one end and tibial bone plug attached at the other. Method 2: Using a graft made of the semitendinosus or gracilis tendon, or both. The graft is then attached with all sorts of screws, bolts, etc... There is a lower reported morbidity related to harvest site using this method.

Question 237

ACL Graft evaluation tibial tunnel

Answer 237

Should parallel the roof of the femoral intercondylar notch. Too Steep = Impinged by femur on extension. Too Flat = Lax & won’t provide stability. Too Far Anterior (“Intersection with Blumensaat line”) = Can lead to pinching at the anterior inferior Normal intercondylar root. Buzzword Root Impingement.

Question 238

ACL Graft evaluation femoral tunnel

Answer 238

Supposedly the primary factor for maintaining length and tension during range of motion. This is referred to as “maintained isometry.”

Question 239

ACL Graft evaluation arthrofibrosis

Answer 239

Can be focal or diffuse (focal is more common). The focal form is the so called “Cyclops” lesion - so named because of its arthroscopic appearance. It’s gonna be a low signal mass-like scar in Hoffa’s fat pad. It’s bad because it limits extension. Buzzword “palpable audible clunk” Seen around 16 weeks - it obviously won’t occur immediately post op because you have to build up your scar.

Question 240

ACL Graft evaluation cyclops lesion

Answer 240

scar associated with ventral graft

Question 241

ACL Graft evaluation trivia 1

Answer 241

The graft is most susceptible to tear in the remodeling process (4-8 months post op).

Question 242

ACL Graft evaluation trivia 2

Answer 242

Other signs of graft tear: grossly high T2 signal (some is ok), fiber discontinuity, uncovering of the posterior horn of the lateral meniscus (secondary sign), anterior tibial translation (secondary sign).

Question 243

ACL Graft evaluation Graft teat

Answer 243

Usually Ortho can just pull on his fucking leg is see if the graft is trashed (anterior drawer sign). For imaging, the simple way to understand this: “flat angle = tear. The ACL should parallel the roof of the intercondylar notch. If the angle becomes flat, a tear is likely.

Question 244

Femoral Tunnel = | Tibial Tunnel =

Answer 244

1 maintains isometry | 2 roof impingement

Question 245

o s te rio r L a te ra l C o rn e r (PLC):

Answer 245

The most complicated anatomy in the entire body. My God this posterior lateral corner! Just think about the LCL, the IT band, the biceps femoris, and the popliteus tendon. The most likely way to show this on a single image (multiple choice style) is edema in the fibular head. Who cares? Missed PLC injury is a very common cause o f ACL reconstruction failure.

Question 246

PCL Tear overview

Answer 246

The posterior collateral ligament is the strongest ligament in the knee. A tear is actually uncommon, it’s more likely to stretch and appear thickened ( > 7 mm). PCL tears should make you think about posterior dislocation as the mechanism o f injury..

Question 247

PCL tear next step/association

Answer 247

If you see a PCL Tear - look at the popliteal flow void. If the knee dislocated posterior, a dreaded consequence is vascular compromise. Depending on the wording o f the question they might need a run-off (watch your back).

Question 248

Meniscal anatomy

Answer 248

The meniscus is “C shaped”, thick along the periphery and thin centrally. Medial meniscus is thicker posteriorly. Lateral meniscus has equal thickness between anterior and posterior portion.

Question 249

Meniscal healing

Answer 249

The Peripheral “Red Zone” is vascular and might heal. The Central “white zone” is avascular and will not heal. The blood supply comes from the geniculate arteries (which enter peripherally).

Question 250

Meniscal tears overview

Answer 250

As stated, the peripheral meniscus (red zone) has better vasculature than the inner 2/3s (white zone) and might heal on its own. In general, you can group tears based on their general direction (as seen on a sagittal section MRI - i.e. the triangles and bowties) - as either vertical (top-to-bottom) or horizontal (front-to-back). You can then sub-group them depending how they look on subsequent sections.

Question 251

Meniscal tears radial tear

Answer 251

``` - Bad because they cause “loss of hoop strength.” - Can lead to extrusion, early OA etc.. ``` ``` Radial Tearing Cuts the Circular Hoop Fibers that Hold the Meniscus Together ```

Question 252

Meniscal tears flap tear (parrot beak)

Answer 252

Radial Tear that Changes Direction into the longitudinal direction

Question 253

Meniscal tears longitudinal tear

Answer 253

``` Can be vertical or horizontal (or mixed oblique patterns) - Defined by a long extension in the axial direction - Vertical Types can flip (bucket- handle) ```

Question 254

Meniscal tears horizontal cleavage tear

Answer 254

``` - Pure cleavage tears extend to the apex - Associated with Meniscal Cysts - Most common in posterior horn of the medial meniscus ```

Question 255

Meniscal tears radial tear classic signs

Answer 255

usually 2 are present truncated triangle cleft (most reliable) ghost or absent triangle

Question 256

Meniscal tears bucket handle tear

Answer 256

This is a tom meniscus (usually medial - 80%) vertical longitudinal sub-type, that flips medially to lie anterior to the PCL.

Question 257

Meniscal tears bucket handle tear gamesmanship

Answer 257

Most likely shown as the classic Aunt Minnie appearance of a “double PCL.” Can also be shown as “not enough bowties,” the opposite of the “too many bowties” look of a discoid meniscus. Only 1 bowtie - instead o f the normal 2. The m iddle o f the second bowtie is flipped medially.

Question 258

Meniscal tears bucket handle trivia

Answer 258

The appearance of a double PCL can only occur in the setting of an intact ACL, otherwise it won’t flip that way. Just know it sorta indirectly proves the ACL is intact (I can just see some knucklehead asking that).

Question 259

Meniscal tears discoid meniscus gamesmanship 1

Answer 259

“Pediatric Patient with Meniscal | Tear”.

Question 260

Meniscal tears discoid meniscus gamesmanship 2

Answer 260

If shown on sagittal they have to show you 3 or more “bow ties” / double triangles.

Question 261

Meniscal tears discoid meniscus bow ties

Answer 261

Normal Meniscus will have 2 bowtie shapes in the sagittal plane - assuming 3mm slices with 1mm gap- Discoid Meniscus will have 3 or more bowties

Question 262

Meniscal tears discoid meniscus gamesmanship 3

Answer 262

``` If shown on coronal they need to show you a meniscus stretching into the notch. ```

Question 263

Discoid meniscus trivia

Answer 263

There are three types, with the most rare and most prone to injury being the Wrisberg Variant.

Question 264

Discoid meniscus trivia

Answer 264

There are three types, with the most rare and most prone to injury being the Wrisberg Variant.

Question 265

Meniscal cysts

Answer 265

Most often seen near the lateral meniscus and are often associated with horizontal cleavage tears.

Question 266

Bakers Cyst

Answer 266

Occurs between the semimembranosus and the MEDIAL head o f the gastroc

Question 267

M e n is c o c a p s u la r S e p a ra tio n

Answer 267

This is a rare (in real life - maybe not on exams) injury. The idea is that the deepest layer o f the MCL complex (capsular ligament) is relatively weak and is the first to tear. This deep tearing may result in the separation o f the meniscus and the MCL. I’ve never seen it occur in isolation (theoretically it can). The important things to remember are probably (1) it happens more with proximal MCL tears, and (2) this is a serious injury — requires immobilization or surgery.

Question 268

M en is c a l Ossicle

Answer 268

This is a focal ossification o f the posterior horn o f the medial meniscus, that can be secondary to trauma or simply developmental. They are often associated with radial root tears.

Question 269

Meniscofemoral ligaments

Answer 269

There are 2 (Wrisberg, Humphry) which can be mimics o f meniscal tears. Wrisberg is in the back ( “humping H um p h ry”). You could also remember that “H” comes before “W” in the alphabet.

Question 270

Meniscal flounce

Answer 270

This an uncommon finding o f a “ ru ffled ” appearance o f the meniscus that mimics a tear. It’s NOT associated with an increased incidence o f tear - but can look like one, if you don’t have any idea what one looks like.

Question 271

Patella Dislocation: overview

Answer 271

Dislocation o f the patella is usually lateral because o f the shape o f the patella and femur. The contusion pattern is classic.

Question 272

Patella Dislocation: points

Answer 272

``` • It’s Lateral • Contusion Pattern - Classic •Associated tear o f the MPFL (medial patellar femoral ligament) •Associated with “Trochlear Dysplasia ” - the trochlea is too flat. ```

Question 273

P a te lla A lta / Baja

Answer 273

The patella will move up or down in certain traumatic situations. If the quadricep tendonmtears you will get unopposed pull from the patellar tendon resulting in a low patella (Baja). If the patella tendon tears you will get unopposed quadriceps tendon pull resulting in a high patella (Alta). The “classic” association with patellar tendon tear (Alta) is SLE, (also can see in elderly,trauma, athletics, or RA).

Question 274

bilateral patellar rupture is a buzzword for

Answer 274

chronic steroids

Question 275

Prepatellar | Bursitis

Answer 275

fluid superficial to the patella

Question 276

fat impingement syndrome

Answer 276

high T2 signal in hoffas fat ingerior to the patella

Question 277

jumpers knee

Answer 277

high t2 signal + thickening of the inferior patella

Question 278

Tib ia l P la te a u F ra c tu re

Answer 278

This injury most commonly occurs from axial loading (falling and landing on a straight leg). The lateral plateau is way more common than the medial. If you see medial, it’s usually with lateral. Some dude named Schatzker managed to get the classification system named after him, o f which type 2 is the most common (split and depressed lateral plateau).

Question 279

pilon fx (tibial plafond)

Answer 279

This injury also most commonly occurs from axial loading, with the talus being driven into the tibial plafond. The fracture is characterized by comminution and articular impaction. About 75% o f the time you are going to have fracture o f the distal fibula.

Question 280

tibial shaft fx

Answer 280

This is the most common long bone fracture. It was also listed as the most highly tested subject in orthopedic OITE exam (with regard to trauma), over the last 8 years. Apparently there are a bunch o f ways to put a nail or plate in it. It doesn’t seem like it could be that high yield for the CORE compared to other fractures with French or Latin sounding names. I will point out that the tibia is one o f the slowest healing bones in the body (10 weeks).

Question 281

Tillaux fx overview

Answer 281

This a Salter-Harris 3, through the anterolateral aspect o f the distal tibial epiphysis.

Question 282

Tillaux fx trivia 1

Answer 282

This pattern requires an open physis along the lateral distal tibia. This is why you see this fracture pattern in the window between the start o f medial physis fusion and the complete fusion o f the lateral physis (lateral physis typically closes around 12-15).

Question 283

Tillaux fx trivia 2

Answer 283

The distal tibial growth plate closes from | medial to lateral (medial first).

Question 284

Triplane fx

Answer 284

This is a Salter-Harris 4, with a vertical component through the epiphysis, horizontal component through the physis, and oblique through the metaphysis. *The addition o f the fracture plane in the posterior distal tibial metaphysis (coronal plane) distinguishes this from the Tillaux.

Question 285

Maisonneuve fx

Answer 285

This is an unstable fracture involving the medial tibial malleolus and/or disruption of the distal tibiofibular syndesmosis. The most common way to show this is to first show you the ankle with the widened mortis, and “next step? ” get you to ask for the proximal fibula - which will show the fracture o f the proximal fibular shaft. This fracture pattern is unique as the forces begin distally in the tibiotalar jo in t and then ride up the syndesmosis to the proximal fibula.

Question 286

Maisonneuve fx trivia

Answer 286

does not extend ino the hindfoot

Question 287

Maisonneuve wide medial malleolus

Answer 287

(+/- Medial Malleolus Fracture) — Distal Tibiofibular syndesmosis +/- Deltoid Lig Injury^

Question 288

maisonneuve proximal fibular fx

Answer 288

— From upwardforce extension | ( “the rippin an d the tearin ”) via the syndesmosis

Question 289

Casanova fx overview

Answer 289

If you see bilateral calcaneal fractures, you should “next s te p ? ” look at the spine (T12-L2) for a compression or burst fracture. These tend to occur in axial loading patterns (possibly from jumping out a window to avoid an angry husband).

Question 290

Casanova fx trivia

Answer 290

* Peroneal tendons can become entrapped with lateral calcaneal fractures. * Calcaneal fractures are the most common (60%) Tarsal Bone Fx * Fractures o f the calcaneus are either extra-articular or intra-articular - depends on subtalar jo in t involvement. Intra-articular fractures will have a fracture line through the “critical angle o f Gissane ”

Question 291

Casanova fx bohlers angle

Answer 291

``` The line drawn between the anterior and posterior borders o f the calcaneus on a lateral view. An angle less than 20 degrees, is concerning for a fracture. ```

Question 292

Casanova fx critical angle of gissane

Answer 292

“More Flat” (More than 130) Equals Depression of the Posterior Facet normal is 95-105

Question 293

Stress fx of the 5th metatarsal

Answer 293

This is considered a high risk fracture (hard to heal).

Question 294

Jones Fx

Answer 294

This is a fracture at the base o f the fifth metatarsal, 1.5cm distal to the tuberosity. These are placed in a non-weight bearing cast (may require internal fixation- because o f risk o f non-union.

Question 295

Avulson fracture of the 5th metatarsal

Answer 295

``` This is more common than a jones fracture. The classic history is a dancer. It may be secondary to tug from the lateral cord of the plantar aponeurosis or peroneus brevis (this is controversial). ```

Question 296

Painful Os Peroneus S yndrom e (POPS)

Answer 296

*Os Peroneus (accessory ossicle) is within the Peroneus LONGUS •This ossicle is seen in about 10% of gen pop •Stress reaction and pain can progress to tendon disruption = POPS

Question 297

Painful Os Peroneus S yndrom e (POPS) key mr findings

Answer 297

Edema in the os peroneus just before the peroneus longus tendon enters the cuboid tunnel

Question 298

L is fra n c In jury: overview

Answer 298

This is the most common dislocation of the foot. The Lisfranc joint is the articulation o f the tarsals and metatarsal bases. This joint is recessed creating a “keystone” locking mechanism, and would make a good place to amputate if you were a surgeon assisting in the Napoleonic invasion o f Russia. The Lisfranc ligament connects the medial cuneiform to the 2nd metatarsal base on the plantar aspect.

Question 299

L is fra n c In jury: keys

Answer 299

* Can't exclude it on a non-weight bearing film * Associated fractures are most common at the base o f the 2nd MT - "Fleck Sign ” * Fracture non-union and post traumatic arthritis are gonna occur if you miss it (plus a lawsuit).

Question 300

L is fra n c In jury: fleck sign

Answer 300

This is a small bony fragment in the Lisfranc Space (between 1st MT and 2nd MT) - that is associated with an avulsion o f the LF ligament.

Question 301

L is fra n c In jury: mechanism

Answer 301

Extreme Plantar Flexion + | Axial Load

Question 302

L is fra n c In jury: ligaments

Answer 302

3 Ligaments make up the complex between the medial cuneiform and 2nd MT. plantar band is the strongest

Question 303

Achilles tendon anatomy trivia

Answer 303

This is the largest tendon in the body. It represents the fused tendons of the gastrocnemius and the soleus muscles. It does NOT have a tendon sheath, so it cannot have a tenosynovitis (fluid in the sheath). Instead inflammatory change around the tendon is referred to as a “paratendinitis.”

Question 304

Lower leg anatomy posteromedial

Answer 304

Tom - tibialis posterio dick - flexor digitorum longus harry - flexor hallucis longus tibial nerve funs by harry

Question 305

lower leg anatomy posterolateral

Answer 305

peroneus longus is more lateral than peroneus brevis

Question 306

The Mythical M a s te r K n o t off H e n ry

Answer 306

This has a funny sounding name, therefore it’s high yield. This is where Dick (FDL) crosses over Harry (FHL) at the medial ankle. Harry starts out lateral relative to Dick. They cross at the “master knot” and then Harry (white) ends up medial on it’s way to the big toe (Harry = Hallucis).

Question 307

The Mythical M a s te r K n o t off H e n ry memory

Answer 307

its a harry dick

Question 308

L ig am e n to u s In ju ry

Answer 308

The highest yield fact is that the anterior talofibular ligament is the weakest ligament and the most frequently injured (usually from inversion).

Question 309

Posteriot tibial tendon injury/dysfunction

Answer 309

This results in a progressive flat foot deformity, as the PTT is the primary stabilizer o f the longitudinal arch. When chronic, the tear is most common behind the medial malleolus (this is where the most friction is). When acute, the tear is most common at the insertion into the navicular bone. Acute Flat Arch should make you think o f PTT tear.

Question 310

Posteriot tibial tendon injury/dysfunction trivia

Answer 310

You will also have a hindfoot valgus deformity (from unopposed peroneal brevis action). The other point o f trivia to know is that the spring ligament is a secondary supporter o f the arch (it holds up the talar head), and it will thicken and degenerate without the help o f the PTT. Don’t get it twisted though, the spring ligament is very thick and strong and almost never ruptures in a foot/ankle trauma.

Question 311

I say acute flat foot and you say

Answer 311

posterior tibial tendon injury

Question 312

Sinus T a rs i Syndrome overview

Answer 312

The space between the lateral talus and calcaneus. The sinus tarsi is not ju st a joint space. It is an important source o f proprioception and balance. Fucking it up has consequences (if your goal is to make prima ballerina assoluta). The “syndrome” is caused by hemorrhage or inflammation o f the synovial recess with or without tears o f the associated ligaments (talocalcaneal ligaments, inferior extensor retinaculum). There are associations with rheumatologic disorders and abnormal loading (flat foot in the setting o f a posterior tibial tendon tear).

Question 313

Sinus T a rs i Syndrome acute

Answer 313

Never make this diagnosis in the setting o f acute trauma

Question 314

Sinus T a rs i Syndrome mri

Answer 314

MRI finding is obliteration of fat in the sinus tarsi space, and replacement with scar.

Question 315

P la n ta r F a s c iitis overview

Answer 315

This is an inflammation o f the fascia secondary to either repetitive trauma (overuse via endless rounding on fat diabetic, smokers as a medicine intern), abnormal mechanics (pes cavus, etc), or arthritis (Reiters, etc...). The pain is localized to the origin o f the plantar fascia, and worsened by dorsiflexion o f the toes. This is usually a clinical diagnosis.

Question 316

P la n ta r F a s c iitis anatomy

Answer 316

``` As a rapid anatomy review, the plantar fascia consists o f 3 bands with the central / lateral part normally thicker than the medial part the thinnest. ```

Question 317

P la n ta r F a s c iitis xray

Answer 317

Plain film might show heel spurs (which are not specific), but could be a hint. A bone scan may show increased tracer in the region o f the calcaneus (from periosteal inflammation).

Question 318

P la n ta r F a s c iitis mri

Answer 318

``` a thickened fascia (> 4m m ), most often the central band with increased T2 signal, most significant near its insertion at the heel. ```

Question 319

classic flat foot progression

Answer 319

Posterior Tibial Tendon Goes Out Spring ligament out Sinus Tarsi gets ja c k e d (including those little proprioception nerves that are in it) You start walking like an idiot, heel striking over and over again Plantar fasciitis

Question 320

Split peroneus brevis

Answer 320

You can see longitudinal splits in the peroneus in people with inversion injuries. The history is usually “chronic ankle pain” . The tendon will be C shaped or boomerang shaped with central thinning and partial envelopment o f the peroneus longus. Alternatively, there may be 3 instead o f 2 tendons. The tear occurs at the lateral malleolus. There is a strong (80%) association with lateral ligament injury.

Question 321

A n te ro la te ra l Im p in g em e n t Syndrome:

Answer 321

Injury to the anterior talofibular ligaments and tibiofibular ligaments (usually from an inversion injury) can cause lateral instability, and chronic synovial inflammation. You can eventually produce a “mass” o f hypertrophic synovial tissue in the lateral gutter. The MRI finding is a “meniscoid mass” in the lateral gutter o f the ankle, which is a balled up scar (T1 and T2 dark).

Question 322

T a rs a l Tu nne l Syndrome:

Answer 322

Pain in the distribution o f the posterior tibial nerve (first 3 toes) from compression as it passes through the tarsal tunnel (behind the medial malleolus). It’s usually unilateral (unlike carpal tunnel which is usually bilateral), unusually “ idiopathic” although pes planus (hindfoot valgus) can predispose by tightening the retinaculum. Having said that, any mass lesion (ganglion cysts, neurogenic tumors, varicosities, lipomas, severe tenosynovitis, and accessory muscles) can cause compression o f the nerve in the tunnel.

Question 323

T a rs a l Tu nne l Syndrome: anatomy and atrophy

Answer 323

Tarsal tunnel is a covered by the flexor retinaculum (arrows) and includes tom, dick, harry the posterior tibial artery and nerve. You can see atrophy of multiple foot muscles (not just minimi as seen with “Baxter”).

Question 324

Mortons neuroma overview

Answer 324

Soft tissue mass (tear drop shaped) shown between the 3rd and 4th metatarsal heads (third intermetatarsal space) is most likely a Morton’s Neuroma (especially on multiple choice tests). The proposed pathology results from compression / entrapment of the plantar digital nerve in this location by the intermetatarsal ligament. Over time this results in thickening and development of perineural fibrosis.

Question 325

Mortons neuroma mulders sign

Answer 325

is a physical exam (a sonographic sign) where you squeeze the patients foot and reproduce the pain (or see the scar pop out under ultrasound).

Question 326

Mortons neuroma trivia

Answer 326

Morton’s Neuroma is NOT a Neuroma (a tumor). | It’s a scar.

Question 327

Mortons neuroma classic look

Answer 327

It is a scar, so it’s gonna be dark on T 1 and T2 | (usually). It is tear drop shaped and projects downward.

Question 328

Mortons neuroma ddx

Answer 328

The reason is that your primary differential is intermetatarsal bursitis - which will extend above the transverse ligament, be fluid signal, and have a more cystic look. Small bursa in this location can be normal as long as the stay smaller than 3mm.

Question 329

Mortons neuroma mri stuff intermetarsal bursitis

Answer 329

bursitis T2 bright bursitis above the ligament (dumbbell shaped) Mortons is T1 Dark Below the Plantar Ligament

Question 330

Haglunds syndrome/deformity

Answer 330

This is also called the “Mulholland deformity” for the purpose of fucking with you. Depending on what you read there are either 3 or 4 classic features. The deformity is the “bump.” The “syndrome” is the bursitis and Achilles tendon thickening. They call this thing the “pump bumps,” because wearing highheeled shoes is supposedly a predisposing factor

Question 331

Haglunds syndrome/deformity classic features

Answer 331

• Retro-Achilles bursitis, / • Retrocalcaneal bursitis, • Thickening of the distal Achilles tendon (insertional portion) • Calcaneal Bony Prominence “prominent posterior superior os calcis”

Question 332

Haglunds syndrome/deformity classic features

Answer 332

• Retro-Achilles bursitis, / • Retrocalcaneal bursitis, • Thickening of the distal Achilles tendon (insertional portion) • Calcaneal Bony Prominence “prominent posterior superior os calcis”

Question 333

Os Trigonum Syndrome overview

Answer 333

The idea is that the Os Trigonum (accessory ossicle) puts the smash on the FHL (“Harry”) during extreme ankle flexion — toe pointing shit (“Pointe technique”) that ballet dancers do ... or other repetitive micro trauma.

Question 334

Os Trigonum Syndrome classic findings

Answer 334

``` (1) “Stenosing” tenosynovitis / collection of fluid around the FHL, and (2) edema within the Os Trigonum and across the synchondrosis between the Os and the Posterior Talus. ```

Question 335

Os Trigonum Syndrome buzzword

Answer 335

ballet dancer

Question 336

Os Trigonum Syndrome mri

Answer 336

Axial T2 - Fluid Around the FHL Edema in the Os and Posterior sag t2 - edema in the o and posterior talus

Question 337

what is this synchonrosis

Answer 337

This is a joint that has essentially no movement and is lined with cartilage.

Question 338

A c h ille s Tendon In jury

Answer 338

Acute rupture is usually obvious with a fluid filled gap. The gap size will determine treatment (big gaps need surgery). The tear is usually 4 cm above the calcaneal insertion and the classic history is an unconditioned middle aged fake athlete (“weekend warrior”) with acute pain and loss of the ability to plantar flex. Without a large gap these things can be very hard to tell apart from a Xanthoma (both can just look like a very thick tendon). There are a few differences that can be used to differentiate - per my chart.

Question 339

Achilles Tendon Tear | partial / small gap

Answer 339

``` Thick Tendon (> 7mm) ``` unilateral associatdd with being a fake athlete step 1 trivia - fluoroquinolones

Question 340

Xanthoma

Answer 340

``` Thick Tendon (> 7mm) ``` bilateral usually associated with having very high cholesterol

Question 341

Plantaris rupture

Answer 341

(“Tennis Leg”): This is usually presented as the classic trick: “Achilles tendon ruptured but can still plantar flex.” Remember not everyone has this tendon (it’s absent in 10% of the population). The classic look on MRI is focal fluid collection between the solcus and the medial head of the gastrocnemius. There is an association with ACL tears.

Question 342

Avulsions of the Calcaneal Tuberosity:

Answer 342

This is sort of an Aunt Minnie with the back of the bone totally ripped off via the Achilles. The classic association is diabetes. When you see this you have to think diabetes.

Question 343

O s teo p en ia

Answer 343

This ju st means increased lucency o f bones. Although this is most commonly caused by osteoporosis, that is not always the case.

Question 344

osteomalacia

Answer 344

This is a soft bone from excessive uncalcified osteoid. This is typically related to vitamin D issues (either renal causes, liver causes, or other misc causes). It generally looks ju st like diffuse osteopenia. For the purpose o f multiple choice you should think about 4 things: Ill-defined trabeculae, Ill-defined corticomedullary junction, bowing, and “ Loosers Zones.”

Question 345

Looser Zones

Answer 345

These things are wide lucent bands that transverse bone at right angles to the cortex. These things can happen in lots o f different locations - but the classic two are the fem o ra l neck and the pubic rami. Typically there is sclerosis surrounding the lucency. You should think two things: osteomalacia and rickets. Less common is 01. The other piece o f trivia is to understand they are a type o f insufficiency fracture. — Raise your suspicion for this shit when you see (1) Symmetric Findings (2) The “90 Degree” to the cortex line

Question 346

Osteopo ro sis overview

Answer 346

The idea is that you have low bone density. Bone density peaks around 30 and then decreases. It decreases faster in women during menopause. The imaging findings are a thin sharp cortex, prominent trabecular bars, lucent metaphyseal bands, and spotty lucencies.

Question 347

Osteopo ro sis causes

Answer 347

Age is the big one. Medications (steroids, heparin, dilantin), Endocrine issues (cushings, hyperthryoidism), Anorexia, and Osteogenesis Imperfecta.

Question 348

Osteopo ro sis complications

Answer 348

Fractures - Most commonly o f the spine (2nd most common is the hip, 3rd most common is the wrist).

Question 349

DEXA things to know

Answer 349

* T score = Density relative to young adult * T score defines osteopenia vs osteoporosis * T score > -1.0 = Normal, -1.0 to -2.5 = Osteopenia, < -2.5 Osteoporosis * Z score = Density relative to age-matched control “to Za Zame Age” * False negative / positive (see below)

Question 350

DEXA fals positive

Answer 350

* Absent Normal Structures: Status post laminectomy

Question 351

DEXA false negative

Answer 351

* Including excessive Osteophytes, dermal calcifications, or metal * Including too much o f the femoral shaft when doing a hip - can elevate the number as the shaft normally has denser bone. * Compression Fx in the area measured

Question 352

FRAX trivia

Answer 352

• FRAX calculates fracture risk at a 10 year probability • FRAX adds “value” by helping to identify the subset o f osteopenic patients who are at a higher risk for fracture - and might benefit from pharmacologic intervention • FRAX is NOT supposed to be used in patient who have already been placed on meds for osteoporosis. The entire point o f the FRAX is to make big pharma more money... 1 mean help identify those who would benefit most from pharmacologic intervention - those already on meds do n ’t need identified. • FRAX is applicable for men and women • FRAX is recommended to calculate 10 year fracture risk in patients with a T-Score between -1 and -2.5. • Some guidelines suggest pharmacologic intervention for patients with a FRAX calculated 10 year hip fracture risk o f > 3% or major fracture risk o f > 20%

Question 353

Reflex Sympathetic Dystrophy (RSD) overview

Answer 353

Also called “Complex Regional Pain Syndrome” — which makes it sound like some Rheumatology Psycho-somatic bullshit (i.e. fibromyalgia). Also called “Sudeck Atrophy” - which makes it sound serious - like some incurable neurodegenerative death sentence. The classic clinical vignette is a history o f trauma or infection.

Question 354

Reflex Sympathetic Dystrophy (RSD) radiographs

Answer 354

On plain film, it can cause severe osteopenia (like disuse osteopenia). Some people say it looks like unilateral RA, with preserved joint spaces. Hand and shoulder are the most common sites o f involvement.

Question 355

Reflex Sympathetic Dystrophy (RSD) bone scan

Answer 355

It’s one o f the many causes o f a 3 phase hot bone scan. In fact, intra-articular uptake o f tracer on bone scan is typically seen (on multiple choice) in patients with RSD (secondary to the increased vascularity o f the synovial membrane), and this is somewhat characteristic.

Question 356

Transient ostoporosis of the hip

Answer 356

For the purpose o f multiple choice tests, by far you should expect to see the female in the 3'" trimester o f pregnancy with involvement o f the left hip. Having said that, it’s actually more common in men in whom it’s usually bilateral. The joint space should remain normal. It’s se lf limiting (hence the word transient) and resolves in a few months. Plain film shows osteopenia, MRI shows Edema, Bone scan shows increased uptake focally.

Question 357

Regional migratory osteoporosis

Answer 357

This is an idiopathic disorder which has a very classic history o f pain in a joint, which gets better and then shows up in another joint. It’s associated with osteoporosis - which is also self-limiting. It’s more common in men.

Question 358

Hip Edema - Strategy Session — This vs That - Transient Osteoporosis vs A V N vs Fx radiograph

Answer 358

On radiograph, transient osteoporosis and AVN look totally different. Transient Osteoporosis is super lucent - so lucent that sometimes you can barely see the femoral head. AVN on the other hand, will have patchy areas o f sclerosis.

Question 359

Hip Edema - Strategy Session — This vs That - Transient Osteoporosis vs A V N vs Fx MRI

Answer 359

On MRI, the story is different. These things can look similar. They both have edema on STIR, and they arc both are dark on T1. The difference is that AVN should be shown with a serpiginous dark line (double line if you are lucky) - that represents infarct core. Joint effusions can be seen in both - so this isn’t helpful.

Question 360

Hip Edema - Strategy Session — This vs That - Transient Osteoporosis vs A V N vs Fx insufficiency fx

Answer 360

Now - if these assholes want to take it to the twilight zone, they can add “insufficiency fracture” to the list o f distractors. This is really a dirty trick as both Transient Osteoporosis and AVN are susceptible to this. The distinction is that this fracture line should be less serpiginous and instead parallel the subchondral bone of the femoral head.

Question 361

Osteoporotic Compression Fracture

Answer 361

Super Common. On MR you want to see a "bandlike" fracture line - which is typically T l dark (T2 is more variable). The nondeformed portions o f the vertebral body should have nonnal signal.

Question 362

Neoplastic Compression | Fracture:

Answer 362

``` Most vertebral mets don’t result in compression fracture until nearly the entire vertebral body is replaced with tumor. If you see abnormal marrow signal (not band like) with involvement o f the posterior margin you should think about cancer. ```

Question 363

What is this “Abnormal Marrow Signal” ?

Answer 363

Normally (in an adult) the marrow of the spine is fatty - so it should be Tl bright. The internal control is an adjacent nonnal disc (not a desiccated disk). If you see dark stuff - it might just be red marrow. BUT if it is darker than the adjacent (nonnal) disc, you have to assume that it’s a bad thing.

Question 364

Neoplastic compression fx next step

Answer 364

Look at the rest o f the spine - mets are often multiple.

Question 365

THIS VS THAT - Osteoporotic Fx vs Neoplastic Fx

Answer 365

If I was going to show a Neoplastic vs Osteoporotic Fracture case, this is how 1 would do it. I would have 2 sequences, a Tl and a STIR. The STIR would be positive (bright on both). The Osteoporotic Fracture would have a T l dark line. The Neoplastic Fracture would be diffusely low Tl signal and blobby - and I would stick a few lesions in other vertebral bodies.

Question 366

THIS VS THAT - Osteoporotic Fx vs Neoplastic Fx

Answer 366

If I was going to show a Neoplastic vs Osteoporotic Fracture case, this is how 1 would do it. I would have 2 sequences, a Tl and a STIR. The STIR would be positive (bright on both). The Osteoporotic Fracture would have a T l dark line. The Neoplastic Fracture would be diffusely low Tl signal and blobby - and I would stick a few lesions in other vertebral bodies.

Question 367

O s te o c h o n d r itis D is s e c a n s (OCD) overview

Answer 367

The new terminology is actually to call these “OCLs” (the “L” is for Lesion). This a spectrum o f aseptic separation o f an osteochondral fragment which can lead to gradual fragmentation o f the articular surface and secondary OA. Most o f the time it is secondary to trauma, although it could also be secondary to AVN.

Question 368

O s te o c h o n d r itis D is s e c a n s (OCD) where it happens

Answer 368

Classic locations include the femoral condyle (most | common site in the knee), patella, talus, and capitellum.

Question 369

O s te o c h o n d r itis D is s e c a n s (OCD staging

Answer 369

* Stage 1: Stable - Covered by intact cartilage, Intact with Host Bone * Stage 2: Stable on Probing, Partially not intact with host bone. * Stage 3: Unstable on Probing, Complete discontinuity o f lesion. * Stage 4: Dislocated fragment

Question 370

O s te o c h o n d r itis D is s e c a n s (OCD treatment/who cares

Answer 370

If the fragment is unstable you can get secondary OA. You want to look for high T2 signal undercutting the fragment from the bone to call it unstable (edema can force a false positive). Thus, the absence o f high T2 signal at the bone fragment interface is a good indicator o f osseous bridging and stability. Granulation tissue at the interface (which will enhance with Gd), does not mean it’s stable.

Question 371

O s te o c h o n d r itis D is s e c a n s (OCD trivia

Answer 371

``` Most common in males under 18 Most common in the lateral aspect of the medial femoral condyle ```

Question 372

Osteochondritis Dissecans of the capitellum quick

Answer 372

Capitellum o f the dom in a n t arm in throwers Anterior convex margin o f the capitellum. Unstable lesions are characterized by high signal fluid th a t encircles the osteochondral fragment on T2W image Can lead to intra-articular loose bodies S lightly older patients (12-16 years)

Question 373

Panners disease (capitellum) quick

Answer 373

Also in th e ca p ite llum o f throwers Entire Capitellum is abnormal in signal d f lP (low T 1, high T2) ``` Loose b o d y fo rmation is NOT seen (usually) ``` 5 to 10 years old “Peter Pan wanted to stay yo u n g ”

Question 374

pseudo-lesion of the capitellum

Answer 374

Posterior capitellum ``` A coronal image through the po s te rio r ca p ite llum can mimic a defect. This o c cu rs because the mos t p o s te rio r portion o f the ca pitellum has an a b ru p t slope. ```

Question 375

O s t e o c h o n d r o s e s

Answer 375

These are a group o f conditions (usually seen in childhood) that are characterized by involvement o f the epiphysis, or apophysis with findings o f collapse, sclerosis, and fragmentation - suggesting osteonecrosis.

Question 376

Kohlers

Answer 376

Tarsal Navicular Boys 4-6. Treatment is not surgical.

Question 377

freiberg infraction

Answer 377

Second Metatarsal Head Adolescent Girls - can lead to secondary OA

Question 378

severs

Answer 378

Calcaneal Apophysis Some say this is a normal “growing pain”

Question 379

panners

Answer 379

Capitellum Kid 5-10 “Thrower”; | does not have loose bodies.

Question 380

perthes (LCP)

Answer 380

Femoral Head White kid; 4-8.

Question 381

Keinbock

Answer 381

Carpal Lunate Associated with negative ulnar | variance. Seen in adults 20-40.

Question 382

Scheuermann

Answer 382

Thoracic Spine Causes kyphosis. 3 adjacent levels with wedging, plus a thoracic kyphosis of > 40 degrees (normal 20-40)

Question 383

Osgood Schlatter disease

Answer 383

Tibial Tubercle Adolescents (10-15) who jump and kick. Need Fragmentation + Soft Tissue Swelling.

Question 384

Sindig larsen johansson

Answer 384

Inferior Patella Adolescents (10-15) who jump.

Question 385

Infection overview

Answer 385

With regard to osteomyelitis, radiographs will be normal for 7-10 days. Essentially, osteomyelitis can have any appearance, occur in any location, and occur at any age. Children have hematogenous spread usually hitting the long bones (metaphysis). Adults are more likely to have direct spread (in diabetic). ``` However, you can have hematogenous spread in certain situations as well (IV Drugs). ```

Question 386

Infection general rule

Answer 386

Septic joints more common in adults. Osteomyelitis more common in kids.

Question 387

Infection classic look

Answer 387

Hallmarks are destruction o f bone and periosteal new bone formation.

Question 388

Osteomyelitis in Spine

Answer 388

Osteomyelitis in Spine = IV Drug User

Question 389

Osteomyelitis in Spine with Kyphosis (Gibbus Deformity) =

Answer 389

TB

Question 390

Unilateral SI joint infection

Answer 390

Unilateral SI joint = IV Drug User

Question 391

Psoas Muscle Abscess =

Answer 391

TB

Question 392

Sequestrum

Answer 392

Piece o f necrotic bone | surround by granulation tissue

Question 393

Involucrum

Answer 393

Thick sheath o f | periosteal bone around sequestrum

Question 394

Cloaca

Answer 394

Defect in the periosteum | (bone skin) caused by infection

Question 395

sinus tract

Answer 395

A channel from the bone to the skin (lined with granulation tissue).

Question 396

Chronic Osteomyelitis timeframe

Answer 396

This is defined as osteomyelitis lasting longer than 6 weeks. Some trivia worth knowing:

Question 397

Chronic Osteomyelitis trivia

Answer 397

• Draining sinus tracts are a risk factor for squamous cell CA • Most specific sign o f active chronic osteomyelitis is the presence o f a sequestrum (best shown with computed tomography) • MRI diagnosis o f healed osteomyelitis is based on the return o f normal fatty marrow

Question 398

A cu te B a c te r ia l O s t e om y e litis overview

Answer 398

can be thought o f in three different categories: 1) hematogenous seeding (most common in child), 2) contiguous spread, and 3) direct inoculation o f the bone either from surgery or trauma.

Question 399

A cu te B a c te r ia l O s t e om y e litis hematogenous

Answer 399

Acute hematogenous osteomyelitis has a predilection for the long bones o f the body, specifically the metaphysis, which has the best blood flow and allows for spreading o f the infection via small channels in the bone that lead to the subperiosteal space.

Question 400

A cu te B a c te r ia l O s t e om y e litis Age < 1 month

Answer 400

Multi-centric involvement, often with joint involvement. Bone scan often negative (75%) at this age

Question 401

A cu te B a c te r ia l O s t e om y e litis Age < 18 months = Spread to epiphysis through blood

Answer 401

Spread to epiphysis through blood In the slightly older baby (<18 months) these vessels from the metaphysis to the epiphysis atrophy and the growth plate stops the spread (although spread can still occur). This creates a “ septic tank” effect. This same thing happens with certain cancers (leukemia); the garbage gets stuck in the septic tank (metaphysis). Once the growth plates fuse, this obstruction is no longer present.

Question 402

A cu te B a c te r ia l O s t e om y e litis Age 2-16 years

Answer 402

Trans-physeal vessels are closed | primary focus is metaphysis

Question 403

MRI fin d in g s o f osteomyelitis

Answer 403

``` Low signal in the bone marrow on Tl imaging adjacent to an ulcer or cellulitis is diagnostic. STIR - High Signal in Bone Adjacent to Ulcer (more sensitive sign) T1 - Corresponding Low Signal (more specific sign) ```

Question 404

The Ghost Sign: Neuropathic Bone vs Osteomyelitis in a Neuropathic Bone

Answer 404

A bone that becomes a ghost (poor definition of margins) on Tl imaging, but then re-appears (more morphologically distinct) on T2, or after giving IV contrast, is more likely to have osteomyelitis.

Question 405

Discitis/Osteomyelitis overview

Answer 405

``` Infection of the disc and infection of the vertebral body nearly always go together. The reason has to do with the route of seeding ```

Question 406

Discitis/Osteomyelitis mechanism

Answer 406

``` (1) Seeding of the vertebral endplate (which is vascular) (2) Eruption and crossing into the disc space (3) Eventual involvement of the adjacent vertebral body ```

Question 407

Discitis/Osteomyelitis early look

Answer 407

* Plain Film: Hard to see | * MR1: Paraspinal and Epidural inflammation, T2 bright disc signal, and disc enhancement.

Question 408

Discitis/Osteomyelitis laterl plain film

Answer 408

* Adjacent irregular endplate destruction. | * Disc Space Narrowing

Question 409

Discitis/Osteomyelitis later mr

Answer 409

* T1 - Dark Marrow * T2 - Bright Marrow * Post Contrast Enhancement

Question 410

Discitis/Osteomyelitis trivia

Answer 410

* Adults: the source is usually from a recent surgery, procedure, or systemic infection. * Children (younger than 5) it’s usually from hematogenous spread. * Step 1 trivia: Staph A is the most common bug, and always think about an IV drug user. * Almost always (80% of the time) the ESR and CRP are elevated. * Gallium is superior to WBC scan in the spine.

Question 411

Discitis/Osteomyelitis epidural abscess

Answer 411

This is an infected collection between the dura and periosteum. ``` Classic Appearance: . T1 Dark, T2 Bright, • Peripheral Enhancement, & • Restricted Diffusion. Classic Scenario: • HIV patient • Bad Diabetic. ```

Question 412

discitis/osteomyelitis paraspinal vs epidural abscess

Answer 412

paraspinal goes to teh front epidural goes to the spinal canal

Question 413

Pediatric Discitis / Osteomyelitis

Answer 413

Children have direct blood supply to the intervertebral disc, so they can get isolated discitis. Isolated Discitis is basically never seen in adults. The classic scenario is: kid (younger than 4) with a upper respiratory infection, now with back pain — usually lumbar.

Question 414

TB overview

Answer 414

This is a special topic (high yield) with regard to MSK infection. It’s not that common, with < 5% o f patients with TB having MSK involvement. Although on multiple choice tests, I think yo u ’ll find it appears with a high frequency.

Question 415

TB potts disease overview

Answer 415

(tuberculosis o f the spine) The vertebral body is involved with sparing o f the disc space until late in the disease (very different than more common bacterial infections).

Question 416

TB potts disease things to know

Answer 416

It tends to spare the disc space It tends to have multi-level thoracic "skip ” involvement Buzzword “Large paraspinal abscess Buzzword “Calcified Psoas Abscess ” Buzzword "Gibbus Deformity ” - which is a destructive fo c a l kyphosis

Question 417

TB gibbus deformity

Answer 417

This is a focal kyphosis seen in “Pott Disease” , among many other thing

Question 418

TB Potts dz mimic

Answer 418

Brucellosis (unpasteurized milk from an Amish P e rso n ), can also have disc space preservation.

Question 419

“ Tuberculosis Dactylitis ” (Spina Ventosa)

Answer 419

Typically seen in kids with involvement o f the short tubular bones o f the hands and feet. It is often a smoldering infection without periosteal reaction. Classic look is a diaphyseal expansile lesion with soft tissue swelling.

Question 420

S e p tic A rth ritis overview

Answer 420

You see this the most in large joints which have an abundant blood supply to the metaphysis (shoulder, hip, knee). IV drug users will get it in the SI joint, an d sternoclavicular joint.

Question 421

S e p tic A rth ritis risk factors

Answer 421

Conventional risk factors include being old, having AIDS, RA, and prosthetic joints.

Question 422

S e p tic A rth ritis plain film

Answer 422

On plain film you might see a joint effusion, or MRI will show synovial enhancement. If untreated this will jack your joint in less than 48 hours.

Question 423

N e c ro tiz in g F a s c iitis

Answer 423

This is a very bad actor that kills very quickly. The good news is that it’s pretty rare, typically only seen in HI Vers, Transplant patients, diabetics, and alcoholics. It’s usually polymicrobial (the second form is Group A Strep). Gas is only seen in a minority o f cases, but if you see gas in soft tissue this is what they want. Diffuse fascial enhancement is what yo u ’d see if the ER is dumb enough to order cross sectional imaging (they often are). Fournier Gangrene is what they call it in the scrotum ( "testes satchel” ).

Question 424

Pneumoarthrogram Sign

Answer 424

If you can demonstrate air within a joint you can exclude a joint effusion. No joint effusion No septic joint

Question 425

Aggressive bone lesions Helms

Answer 425

According to Helms, the wide zone of transition is the best sign that a lesion is aggressive. This is actually a useful pearl. The simplest way to conceptualize this is to ask yourself if you can trace the edges of the lesion with a pencil. If you can the lesion is probably benign. If the edges are blurry or there is a gradient to the edge - this is a more likely an aggressive lesions.

Question 426

Aggressive bone lesions MArgins

Answer 426

The reason is that margins reflect the growth the lesion. Bones are dumb. They really only know how to do two things - make bone and destroy bone. The margins are the reflection of bone formation. If the margins are sharp and sclerotic, this means the bone has time to adjust to the irritation and lay down a coat of mature bone. If the margins are not distinct (zone of transition is wide) this indicates a faster growing lesion and therefore a higher probability of malignancy (or infection).

Question 427

Aggressive bone lesions | growth

Answer 427

If the tumor grows rapidly enough it can break through the cortex and destroy thenewly formed bone capsule / lamellated bone. When this happens you end up with a triangular structure - called the Codman triangle (as shown in diagram).

Question 428

Aggressive bone lesions Lytic

Answer 428

When we think about bone lesions, we often imagine lytic holes or bone destruction. Bone destruction occurs from complex methods best understood as either direct obliteration via the tumor or pissed off osteoclasts enraged by the uninvited tumor / hyperemia. Trabecular bone loss occurs more rapidly (relative to cortical bone), but is noticed later because cortical bone is more smooth and organized. Supposedly you need to destroy 70% of the trabecular bone before it is noticed radiographically.

Question 429

Aggressive bone lesions bone destruction

Answer 429

Bone destruction that occurs in a uniform geographic pattern (especially with a sharp well defined border) is more suggestive of a benign slow growing lesion. A moth-eaten (cluster of small lytic holes) or permeative (ill-defined tiny oval or streak like (luccncies) suggests rapid infiltrative tumor growth — as seen in myeloma, lymphoma, and Ewings sarcoma. It is worth noting that osteomyelitis and hyperparathyroidism can also demonstrate Moth Permeative these aggressive patterns - pre-test probably is always important.

Question 430

Osteosarcoma overview

Answer 430

There are a bunch o f subtypes, but for the purpose o f this discussion there are 4. Conventional Intramedullary (85%), Parosteal (4%), Periosteal (1%), Telangiectatic (rare). All the subtypes produce bone or osteoid from neoplastic cells. Most are idiopathic but you can have secondary causes (usually seen in elderly) XRT, Pagets, Infarcts, etc ...

Question 431

Osteosarcoma conventional intramedullary

Answer 431

More common, and higher grade than the surface subtypes (periosteal, and parosteal). Primary subtypes typically occur in young patients (10-20). The most common location is the femur (40%), and proximal tibia (15%).

Question 432

Osteosarcoma buzzwords (conventional)

Answer 432

“S u n b u rst”- periosteal reaction that is aggressive and looks like a sunburst Codman triangle - With aggressive lesions, the periosteum does not have time to ossify completely with new bone (e.g. as seen in single layer and multi-layered periosteal reaction), so only the edge o f the raised periosteum will ossify - creating the appearance o f a triangle. Lamellated (onion skin reaction) - multi layers o f parallel periosteum, looks like an onion’s skin.

Question 433

Osteosarcoma trivia

Answer 433

Osteosarcoma met to the lung is a “classic” cause o f occult pneumothorax.

Question 434

Osteosarcoma reverse zoning phenomenon

Answer 434

more dense mature matrix in the center, less peripherally (opposite o f myositis ossificans)

Question 435

Osteosarcoma reverse zoning phenomenon

Answer 435

more dense mature matrix in the center, less peripherally (opposite o f myositis ossificans)

Question 436

P a ro s te a l O s te o s a rc om a

Answer 436

Generally low grade, BULKY parosteal bone formation. Think B ig ... ju st say Big. This guy loves the posterior distal femur (because o f this location it can mimic a cortical d esmoid "tug lesion ” early on). The lesion is metaphyseal 90% o f the time. The buzzword is “string sign” - which refers to a radiolucent line separating the bulky tumor from the cortex.

Question 437

P e rio s te a l | O s te o s a rc om a :

Answer 437

``` Worse prognosis than parosteal but better than conventional osteosarcoma. Tends to occur in the diaphyseal regions, classic medial distal femur. ```

Question 438

Parosteal this vs that

Answer 438

early adult/middle age metaphyseal likes posterior distal femur marrow extension low grad

Question 439

Periosteal this vs that

Answer 439

15-25 diaphyseal likes medial distal femur usually no marrow extension intermediate grade

Question 440

T e la n g ie c ta tic O s te o s a rc om a :

Answer 440

About 15% have a narrow zone o f transition. Fluid-Fluid levels on MRI is classic. They are High on T1 (from methemoglobin). Can be differentiated from ABC or GCT (maybe) by tumor nodularity and enhancement.

Question 441

Bone lesion fluid-fluid level DDX

Answer 441

Telangiectatic Osteosarcoma Aneurysmal Bone Cyst Giant Cell Tumor

Question 442

Chondrosarcoma overview

Answer 442

Usually seen in older adults (M>F). Likes flat bones, limb girdles, proximal tubular bones. Can be central (intramedullary) or peripheral (at the end o f an osteochondroma). Most are low grade.

Question 443

Chondrosarcoma risk factors

Answer 443

Pagets, and anything cartilaginous | osteochondromas, Maffucci etc...

Question 444

Chondrosarcoma gamesmanship 1

Answer 444

If you want to say chondroblastoma but | it’s an adult think clear cell chondrosarcoma

Question 445

Chondrosarcoma gamesmanship 2

Answer 445

If shown with CT - they have to show you some “chondroid matrix” - “arcs and rings”

Question 446

THIS vs THAT Enchondroma vs Low Grade Chondrosarcoma

Answer 446

Factors Favoring Chondrosarcoma: ``` Pain Cortical Destruction Scalloping of > 2/3 of the cortex >5cm in Size “Changing Matrix” ```

Question 447

Ewings overview

Answer 447

Extremely rare in African-Americans. Likes to met bone to bone (skip lesions are more common in Ewings, relative to Osteosarcoma). Does NOT form osteoid from tumor cells, but can mimic osteosarcoma because of its marked sclerosis (sclerosis occurs in the bone only, not in the soft tissue - which is NOT the case in osteosarcoma).

Question 448

Ewings imaging

Answer 448

Permeative lesion in the diaphvsis of a child = Ewings | could also be infection, or EG

Question 449

Chordoma overview

Answer 449

Usually seen in adults (30-60), usually slightly younger in the clivus and slightly older in the sacrum. Most likely questions regarding the chordoma include location (most common sacrum, second most common clivus, third most common vertebral body), and the fact that they are verv T2 bright.

Question 450

Chordoma most commons

Answer 450

* Most common primary malignancy of the spine. * Most common primary malignancy of the sacrum. * When involving the spine, most common at C2.

Question 451

I say chordoma you say

Answer 451

Midline, Midline, Midline!’’ Why is it always midline? It’s made of cells left over from the “notochord” (some embryology bullshit that was involved in making MIDLINE structures). Chordomas arc NEVER EVER seen off the midline (NEVER in the hip, leg, arm, hand, etc...).

Question 452

Lucent lesions overview

Answer 452

FEGNOMASHIC is a “useful” mnemonic for lucent bone lesions made popular by Clyde Helms. As it turns out, you can rearrange the letters of FEGNOMASHIC to form a word FOGMACHINES. I find it a lot easier to remember a mnemonic if it actually forms a real word. Having said that, the whole idea of memorizing a list o f 11 or 12 barely related things is stupid. You would never give a differential that included all o f those, as they occur in different places, in different ages, and often look very different. Differentials (for people who know what they are looking at) are usually never deeper than 3 or 4 things. If you are giving a differential o f 12 things, just say you don’t know what it is. Seriously in the real world bone lesions only come in 3 flavors: 1 - Bad (cancer or infection), 2 - Obviously benign (not sure I’ll waste saliva mentioning it in my rep o rt), 3 - Ehh hard to tell - get a follow up. This is actually pretty much true of lesions everywhere in the body. Realizing this allows for the following paradigm shift:

Question 453

Lucent lesions multiple choice

Answer 453

For multiple choice, when you encounter a lucent bone lesion you can expect one o f two questions (1) what is it ? or (2) what is it associated with ? In either case you are going to need to figure out what it is. In the real world you would probably have to give a short differential, but in the world of multiple choice you will have to come up with one answer. Don’t fret, they have to give you clues so you can pick just one. A useful mental exercise when eliminating multiple choice distractors is to ask yourself “why is it NOT this?” It’s an exercise that is often not performed at the workstation - but very valuable in the test environment - especially for these types o f questions.

Question 454

Lucent lesions age - key facts

Answer 454

. <30 = EG, ABC, NOF, Chondroblastoma, and Solitary Bone Cysts • Any Age = Infection • > 40 = Mets and Myeloma (unless it’s neuroblastoma mets).

Question 455

Lucent lesions method

Answer 455

(1) Age o f the patient? - If you are lucky they will tell you. If you are less lucky you will have to guess. Growth plates open = kid. Growth plates closed with no degenerative change = young adult. Growth plates closed with degenerative changes = older than 40. (2) Location o f the lesion ? Metaphysis, Epiphysis, Diaphysis? Is this an epiphyseal equivalent discussion (see the next page for discussion). (3) Classic Locations and Looks ?

Question 456

Lucent lesions epiphysis

Answer 456

In general, only a few lesions tend to arise in the epiphysis. The “four horseman o f the (e)apophysis” is the mnemonic 1 like to use, and I think about the company AIG that was involved in some scandal a few years ago. AIG “the evil” Company. ABC, Infection, Giant Cell, and Chondroblastoma. * The caveat is that ABC is usually metaphyseal hut after the growth plate closes it can extend into the epiphysis.

Question 457

lucent lesions epiphysis malignant

Answer 457

For the purpose o f multiple choice tests, it is important to not forget about the malignant tumor at the end o f the bone (epiphysis) - Clear Cell Chondrosarcoma. This guy is slow growing, with a variable appearance (lytic, calcified, lobulated, ill defined, e tc ...). Just remember if they say malignant epiphyseal you say Clear Cell Chondrosarcoma.

Question 458

Lucent lesions epipyseal equivalents

Answer 458

(bones that will have the same lesions as the epiphysis) Carpals, Patella, Greater Trochanter, Calcaneus

Question 459

Lucent lesions metaphysis

Answer 459

The metaphysis is the fastest growing area o f a bone, with the best blood supply. This excellent blood supply results in an increased predilection for Mets and Infection. Most o f the cystic bone lesions can occur in the metaphysis.

Question 460

lucent lesions diaphysis

Answer 460

Just like the metaphysis, most entities can occur in the diaphysis (they ju st do it less).

Question 461

mccune albright

Answer 461

polyostotic fibrous dysplasia girl cafe au lait spots precocious puberty

Question 462

mazabraud

Answer 462

polyostotic fibrous dysplasia woman soft tissue myxomas increase risk osseous malignant transformation

Question 463

fibrous dysplasia age

Answer 463

The disorder can occur at any age - but the multiple lesion variety “polyostotic” - tends to occur earlier. You could think monostotic (20’s & 30’s) or polyostotic (< 10 year old). When you see the polyostotic form (often with a mangled horrible horrible face... a face that only a mother could love) - you should think syndromes.

Question 464

adamantinoma

Answer 464

A total zebra (probably a unicorn). A tibial lesion that resembles Fibrous dysplasia (mixed lytic and sclerotic). It is potentially malignant.

Question 465

Nonossifying fibroma

Answer 465

These are very common. They arc seen in children, and will spontaneously regress (becoming more sclerotic before disappearing). They are rare in children not yet walking. Just like GCTs they like to occur around the knee. They are classically described as eccentric with a thin sclerotic border (remember GCTs don’t have a sclerotic border). They are called fibrous cortical defects when smaller than 2 cm.

Question 466

nonossifying fibroma vocab

Answer 466

NOFs are the larger version (> 3cm) of a fibrous cortical defect (FCD). A wastebasket term for the both of them is simply “fibroxanthoma."

Question 467

a ffe -C am p a n a c c i Syndrome

Answer 467

Syndrome of multiple NOFs, cafe-au-lait | S? sf spots, mental retardation, hypogonadism, and cardiac malformations.

Question 468

Enchondroma overview

Answer 468

This guy is a tumor of the medullary cavity composed of hyaline cartilage. They become progressively more common with age - peaking around 10-30 years old. The sneaky thing about this lesion is that it looks different depending on the body part it is in. * Humerus or Femur = Arcs and Rings * Fingers or Toes = Lytic The enchondroma is actually the most common cystic lesion in the hands and feet. Just like fibrous dysplasia, this lesion does not have periostitis.

Question 469

Enchondroma appearance

Answer 469

The ARCS AND RINGS is the more classic textbook look with the irregularly speckled calcification of chondroid matrix. Just don’t forget that this classic matrix is not found in the fingers or toes.

Question 470

Differentiating Enchondroma vs Low Grade Chondrosarcoma Strategies to Deal with the Chondroid Matrix Lesion in a Long Bone primary tactic

Answer 470

History of pain — Enchondroma vs a Low Grade Chondrosarcoma Not Painful PAINful (respectively)

Question 471

Differentiating Enchondroma vs Low Grade Chondrosarcoma ▼ f Strategies to Deal with the Chondroid Matrix Lesion in a Long Bone secondary tactic

Answer 471

Enchondroma vs a Low Grade Chondrosarcoma 1-2 cm > 4-5 cm (respectively)

Question 472

Differentiating Enchondroma vs Low Grade Chondrosarcoma ▼ f Strategies to Deal with the Chondroid Matrix Lesion in a Long Bone tertiary tactic

Answer 472

Glitch in the matrix - Enchondroma vs a Low Grade Chondrosarcoma Arcs & Rings Arcs & Rings Pattern Pattern does NO T Changes - Change around grows etc...

Question 473

Differentiating Enchondroma vs Low Grade Chondrosarcoma ▼ f Strategies to Deal with the Chondroid Matrix Lesion in a Long Bone tertiary tactic

Answer 473

Glitch in the matrix - Enchondroma vs a Low Grade Chondrosarcoma Arcs & Rings Arcs & Rings Pattern Pattern does NO T Changes - Change around grows etc...

Question 474

Ollier disease

Answer 474

multiple enchondromas (3 or more) slight increase in risk in chondrosarcoma

Question 475

Maffucci syndrome

Answer 475

“Marffucci Has More” More Cancer Risk and More Vascular Malformations multiple enchondromas Hemangiomas (bunch lucent centered calcifications) Increase risk in Chondrosarcoma (probably more than Oilier)

Question 476

Eos in oph ilic G ran u lom a (EG): overview

Answer 476

This is typically included in every differential for people less than 30 (peak age is 5-10). It can be solitary (usually) or multiple.

Question 477

Eos in oph ilic G ran u lom a (EG): classic appearances

Answer 477

(1) Vertebra plana in a kid (2) Skull with lucent “beveled edge” lesions (also in a kid). (3) “Floating Tooth” with lytic lesion in alveolar ridge — this would be a differential case The appearance is highly variable and can be lytic or blastic, with or without a sclerotic border, and with or without a periosteal response. Can even have an osseous sequestrum.

Question 478

lucent lesions Classic DDx for Vertebra Plana

Answer 478

mets/myeloma eg lymphoma trauma/TB (MELT)

Question 479

lucent lesions Classic DDx for Osseous Sequestrum:

Answer 479

osteomyelitis lymphoma fibrosarcoma EG ^osteoid osteoma can mimic a sequestrum

Question 480

Giant cell tumors key criteria

Answer 480

- Physis MUST be closed - Non Sclerotic Border - Abuts the articular surface

Question 481

Giant cell tumors trick

Answer 481

Another trick is to show you a pulmonary met, and ask if it could be a GCT? The answer is yes (although this is rare) GCT is considered “quasi-malignanf ’ because it can be locally invasive and about 5% will have pulmonary mets (which are still curable by resection). As a result o f this, it should be resected with wide margins.

Question 482

Giant cell tumors things to know

Answer 482

- Most common in the knee - abutting the articular surface - Most common at age 20-30 * physis must be closed - There is an association with ABCs (they can turn into them) - They are “quasi-malignant” - 5% have lung mets - Fluid levels on MRI

Question 483

Giant cell tumors things to know

Answer 483

- Most common in the knee - abutting the articular surface - Most common at age 20-30 * physis must be closed - There is an association with ABCs (they can turn into them) - They are “quasi-malignant” - 5% have lung mets - Fluid levels on MRI

Question 484

Osteoid osteoma classic

Answer 484

pain at night relieved by aspirin

Question 485

Osteoid osteoma classic age

Answer 485

Adolescent” — 10-25 ish.

Question 486

Osteoid osteoma classic look

Answer 486

Oval lytic lesion (“ lucent nidus”) surrounded by dense sclerotic cortical bone (“periosteal reaction”).

Question 487

Osteoid osteoma classic location

Answer 487

(1) Meta/diaphysis o f long bones (femoral neck = most common) and (2) Posterior elements of the spine (lumbar > cervical > thoracic). Technically the fingers arc more common than the spine, but that’s rarely show on multiple choice.

Question 488

Osteoid osteoma mri

Answer 488

“Lots o f edema.” I’ll say that again “large amount o f edema fo r the size o f the lesion. ” Adjacent soft tissue edema is also common - don’t let that fool you.

Question 489

Osteoid osteoma nuke bone scan

Answer 489

Double Density Sign” - very intense central activity at nidus, surrounded by less intensity o f reactive bone. A common distractor is a stress fracture. Stress fractures are linear. O.O. should be round.

Question 490

Osteoid osteoma scoliosis trivia

Answer 490

When you have them in the spine (most common in the posterior elements o f the lumbar spine), you frequently have an associated painful scoliosis with the convexity pointed away from the lesion.

Question 491

Osteoid osteoma treamtent

Answer 491

These can be treated with percutaneous radiofrequency ablation (as long as it’s not within 1 cm o f a nerve or other vital structure - typically avoided in hands, spine, and pregnant patients).

Question 492

Osteoid osteoma associations

Answer 492

Painful Scoliosis Growth Deformity: Increased length and girth of long bones Synovitis: Can be seen if intra-articular, joint effusions Arthritis: Can occur from primary synovitis, or secondarily from altered joint mechanics.

Question 493

O s te o b la s tom a

Answer 493

Basically it’s an osteoid osteoma that is larger than 2 cm. It’s seen in patients < 30 years old. They are most likely to show this in the posterior elements. It also occurs in the long bones (35%) and when it does it is usually diaphyseal (75%).

Question 494

A n eu ry sm a l Bone Cyst (ABC): overview

Answer 494

Aneurysmal bone cysts are aneurysmal lesions o f bone with thinwalled, blood-filled spaces (fluid-fluid level on MR1). Patients are usually < 30. They may develop following trauma. They can be described as primary ABC, presumably arising denovo or secondary ABC, associated with another tumor (classic GCT). They are commonly associated with other benign lesions.

Question 495

A n eu ry sm a l Bone Cyst (ABC): thinks to knowq

Answer 495

- Up to 40% o f secondary ABC's are associated with giant cell tumor o f bone. - It's on the DDx for Fluid - Fluid Level on MRI - Patient < 30 - Tibia is the most common site

Question 496

A n eu ry sm a l Bone Cyst (ABC): location

Answer 496

Location: Tibia > Vert > Femur > Humerus

Question 497

Classic DDx for Lucent Lesion in Posterior Elements:

Answer 497

Osteoblastoma ABC TB

Question 498

S o lita ry (U n ic am e ra l) Bone Cyst overview

Answer 498

It would be unusual to see one o f these in a patient older than 30. Most common in the tubular bones (90-95 %) usually humerus or femur. Unique feature: “Always located centrally.”

Question 499

S o lita ry (U n ic am e ra l) Bone Cyst imaging

Answer 499

It’s going to be shown one o f two ways: (1) With a fracture through it in the humerus (probably with a fallen fragment sign) or (2) As a lucent lesion in the calcaneus (probably with a fallen fragment sign).

Question 500

S o lita ry (U n ic am e ra l) Bone Cyst fallen fragment sign

Answer 500

(bone fragment in the dependent portion o f a lucent bone lesion) is pathognomonic o f solitary bone cyst.

Question 501

Brown T um o r (H y p e rp a ra th y ro id ism ): ovvervview

Answer 501

The “brown tumor” represents localized accumulations o f giant cells and fibrous tissue (in case someone asks). They appear as lytic or sclerotic lesions with other findings o f hyperparathyroidism (subperiosteal bone resorption). In other words, they need to tell you he/ she has hyperparathyroidism first. They may ju st straight up tell you, or they will show you some bone resorption first (classically on the side o f a finger, edge o f a clavicle, or under a rib).

Question 502

Brown T um o r (H y p e rp a ra th y ro id ism ): healing

Answer 502

These things have different stages o f healing / sclerosis. They resorb and can become totally sclerotic / healed, when the Hyper PTH is treated.

Question 503

Chondroblastoma overview

Answer 503

This is seen in kids (90% age 5-25). They classically show it in two ways (1) in the epiphysis o f the tibia on a 15 year old, or (2) in an epiphyseal equivalent.

Question 504

what are epiphyseal equivalents

Answer 504

* Patella * Calcaneus * Carpal Bones * A n d all the Apophyses (greater an d less trochanter, tuberosities, etc...)

Question 505

Chondroblastoma features

Answer 505

A thin sclerotic rim, extension across the physeal plate (25-50%), periostitis (30%). Actual location: femur > humerus > tibia . This may show bone marrow edema, and soft tissue edema on MR1 (MRI can mislead you into thinking it’s a bad thing). This is one o f the only bone lesions that is often NOT T2 bright. They tend to reoccur after resection (like 30% o f the time).

Question 506

Chondroblastoma gamesmanship hip

Answer 506

When you have a chondroblastoma in the hip, it tends fa v o r the greater trochanter (more than the femoral epiphysis).

Question 507

Chondroblastoma gamesmanship hip

Answer 507

When you have a chondroblastoma in the hip, it tends fa v o r the greater trochanter (more than the femoral epiphysis).

Question 508

C hondromyxoid Fibroma

Answer 508

This is the least common benign lesion o f cartilage. It is usually in patients younger than 30. The typical appearance is an osteolytic, elongated in shape, eccentrically located, metaphyseal lesion, with cortical expansion and a “bite” like configuration. Sorta looks like an NOF - with the classic location in the proximal metaphyseal region o f the tibia.

Question 509

Lucent lesions greater trochanter - hip

Answer 509

Remember this is an epiphyseal equivalent and the chrondroblastomas prefer it to the femoral epiphysis. You can get all the other DDxs (ABC, Infection, GCT, etc ... here as well). Plus, you can have avulsions o f the gluteus medius and minimus.

Question 510

lucent lesions lesser trochanter - hip

Answer 510

An avulsion here without significant clinical history should make you think pathologic fracture.

Question 511

Lucent lesions intertrochanteric region - hip

Answer 511

Classic DDx here: Lipoma, Solitary Bone Cyst, and Monostotic Fibrous Dysplasia.

Question 512

Classic (& sneaky non-classic) Lesions that can be shown in the calcaneus geod

Answer 512

Older Patient + Subtalar degenerative change / Obvious Arthritis

Question 513

Classic (& sneaky non-classic) Lesions that can be shown in the calcaneus osteomyelities/mets

Answer 513

The calcaneal apophysis (equivalent to the metaphyseal region o f long bones) will have a similar predilection for collection hematogenous spread of both infection or cancer (GU or Colon). In both cases the involvement favors the posterior meta-epiphvseal region (which has the richest blood supply), with lesions potentially growing large enough to involve the entire calcaneus.

Question 514

Classic (& sneaky non-classic) Lesions that can be shown in the calcaneus overview

Answer 514

The suggested Promethean method is to first use location within the bone, and then use characteristic appearance as a secondary discriminator. First let us take a closer look at the calcaneus. Remember this thing is an epiphyseal equivalent, but only in certain locations. It’s probably better to think about the bone like a hybrid long bone - complete with a diaphysis, two metaphysis, and three epiphysis

Question 515

Classic (& sneaky non-classic) Lesions that can be shown in the calcaneus chondroblastoma

Answer 515

Most classic epiphysis lesion - with a preference for the superior epiphysis near the talocalcaneal articulation (although they can be at any of the 3 epiphysis). Lucent lesion, that can have some internal calcifications.

Question 516

Classic (& sneaky non-classic) Lesions that can be shown in the calcaneus giant cell tumor

Answer 516

Can also involve the epiphysis (although it typically starts out metaphyseal and grows into the epiphysis). Remember these things required a closed physis. The Posterior Metaphysis / Epiphysis is favored.

Question 517

Classic (& sneaky non-classic) Lesions that can be shown in the calcaneus osteoid osteoma

Answer 517

Talus > Calcaneus Similar to Chondroblastoma in favoring the superior epiphysis near the talocalcaneal articulation. Distinction is the sclerotic thickening of the adjacent bone and the radiolucent nidus.

Question 518

Classic (& sneaky non-classic) Lesions that can be shown in the calcaneus pseudo-cyst

Answer 518

This is a variation on the normal trabecular pattern, which creates a central triangular radiolucent area. This area is sometimes called the “pseudo-cyst triangle” and is obnoxiously located in the same anterior 1/3 as the SBC and Lipoma. Supposedly the persistence of thin trabeculae, visible nutrient foramen, and the classic location are helpful in telling it from the other benign entities.

Question 519

bone lesions mets overview

Answer 519

Should be on the differential for any patient over 40 with a lyticlesion. As a piece o f trivia renal cancer is ALWAYS lytic (usually).

Question 520

bone lesions classic blastic lesions

Answer 520

prostate, carcinoid, medulloblastoma

Question 521

bone lesions classic lytic lesions

Answer 521

renal and thyroid

Question 522

bone lesions next step

Answer 522

Prostate Met vs Bone Island??? - Get a Bone Scan • Bone Island should be mild (or not active) • Prostate Met should be HOT

Question 523

M u ltip le M y e lom a (MM ) overview

Answer 523

Plasma cell proliferation increases surrounding osteolytic activity (in case someone asks you the mechanism). Usually in older patient (40’s-80’s). Plasmacytomas can precede clinical or hematologic evidence o f myeloma by 3 years.

Question 524

M u ltip le M y e lom a (MM ) imaging

Answer 524

They usually have discrete margins, and can be solitary or multiple. Vertebral body destruction with sparing o f the posterior elements is classic. Bone Scan is often negative, skeletal survey is better (but horribly painful to read), and MRI is the most sensitive.

Question 525

M u ltip le M y e lom a (MM ) classic scenario

Answer 525

MM manifesting as Diffuse Osteopenia

Question 526

myeloma related conditions plasmacytoma

Answer 526

(usually under 40): This is a discrete, solitary mass o f neoplastic monoclonal plasma cells in either bone or soft tissue (extramedullary subtype). It is associated with latent systemic disease in the majority o f affected patients. It can be considered as a singular counterpart multiple myeloma. The lesions look like a geographic lytic area, sometimes with expansile remodeling.

Question 527

mini brain appearance

Answer 527

Plasmacytoma in vertebral body

Question 528

POEMS

Answer 528

This is basically “Myeloma with Sclerotic Mets.” It’s a rare medical syndrome with plasma cell proliferation (typically m y e lom a ), neuropathy, and organomegaly.

Question 529

POEMS

Answer 529

This is basically “Myeloma with Sclerotic Mets.” It’s a rare medical syndrome with plasma cell proliferation (typically m y e lom a ), neuropathy, and organomegaly.

Question 530

Lucent Lesion Classic Looks and Locations Long Lesion in a Long Bone

Answer 530

Fibrous dysplasia

Question 531

Lucent Lesion Classic Looks and Locations ground glass

Answer 531

fibrous dysplasia

Question 532

Lucent Lesion Classic Looks and Locations lyst lesion with a hazy matrix

Answer 532

fibrous dysplasia

Question 533

Lucent Lesion Classic Looks and Locations chondroid matrix in the proximal humerus or distal femur

Answer 533

cnchondroma

Question 534

Lucent Lesion Classic Looks and Locations lucent lesion int he finger or toe

Answer 534

enchondroma

Question 535

Lucent Lesion Classic Looks and Locations epiphyseal tibial lesion in a teenager

Answer 535

chondroblastoma

Question 536

Lucent Lesion Classic Looks and Locations epiphyseal equivalent lesion

Answer 536

chondroblastoma or iant cell tumor technically GCTs grow into the epiphysis

Question 537

Lucent Lesion Classic Looks and Locations lucent lesion in the greater trochanter

Answer 537

chondroblastoma

Question 538

Lucent Lesion Classic Looks and Locations lusent lesion with a gracture (fallen fragment) in the humerus

Answer 538

solitary bone cyst

Question 539

Lucent Lesion Classic Looks and Locations calcaneal lesion with central calcification

Answer 539

lipoma

Question 540

Lucent Lesion Classic Looks and Locations lucent lesion in the skull

Answer 540

eg

Question 541

Lucent Lesion Classic Looks and Locations vertebra plana in a kid

Answer 541

eg

Question 542

Lucent Lesion Classic Looks and Locations vertebra plana in an adult

Answer 542

mets

Question 543

Lucent Lesion Classic Looks and Locations sequestrum/nidus in the tibia/femur

Answer 543

osteoid osteom

Question 544

Lucent Lesion Classic Looks and Locations painful scoliosis

Answer 544

osteoid osteoma

Question 545

Lucent Lesion Classic Looks and Locations calcificed lesion in the posterior element of the c spine

Answer 545

osteoblastoma

Question 546

Solitary vs Multiple (Generalization for Multiple Choice Trivia) multiple sclerotic lesions

Answer 546

mets

Question 547

Solitary vs Multiple (Generalization for Multiple Choice Trivia) multiple sletoritc lesions centered around a joint

Answer 547

osteopoikolosis

Question 548

Solitary vs Multiple (Generalization for Multiple Choice Trivia) multiple lucent lesions older than 49

Answer 548

Mets, Myeloma, Metastatic Non-Hodgkin Lymphoma

Question 549

Size matters Nidus < 2.0 cm

Answer 549

osteoid ostema

Question 550

Size matters Nidus > 2.0 cm

Answer 550

osteoblastoma

Question 551

Size matters Well-defined lytic lesion in the cortex of a long bone with a sclerotic rim < 3 cm

Answer 551

fibrous corticald efect

Question 552

Size matters Well-defined lytic lesion in the cortex of a long bone with a sclerotic rim > 3 cm

Answer 552

noonossifying fibroma

Question 553

Size matters Chondral lesion in a long bone 1-2 cm

Answer 553

probably an enchondroma

Question 554

Size matters Chondral lesion in a long bone > 4-5 cm

Answer 554

increased risk of low grade chondrosarcoma

Question 555

Size matters Chondral lesion in a long bone > 4-5 cm

Answer 555

increased risk of low grade chondrosarcoma

Question 556

Liposclerosing Myxofibroma

Answer 556

Very characteristic location - at the intertrochanteric region o f the femur. Looks like a geographic lytic lesion with a sclerotic margin. Despite nonaggressive appearance. 10% undergo malignant degeneration so they need to be followed.

Question 557

osteochondroma overview

Answer 557

Some people think o f this as more o f a developmental anomaly (although they still always make the tumor chapter). Actually, it’s usually listed as the most common benign tumor (“exostosis”). They can be radiation induced, making them the only benign skeletal tumor associated with radiation.

Question 558

osteochondroma malignant transformation

Answer 558

They have a very small risk of malignant transformation (which supposedly can be estimated based on size o f cartilage cap). Supposedly a cap > 1.5 cm is concerning.

Question 559

osteochondroma key points

Answer 559

Key Points: • They point away from the joint • The bone marrow flows freely into the lesion

Question 560

Multiple H e re d ita ry Exostosis

Answer 560

AD condition with multiple osteochondromas. | They have an increased risk of malignant transformation.

Question 561

Trevor Disease (Dysplasia Epiphysealis H em ime lic a - DEH):

Answer 561

This is a disease characterized by the development of osteochondromas develop at the epiphysis which result in significant joint deformity (most common in ankle and knee) — making you terrible at tennis and soccer. Instead o f pointing away from the joint (like a normal osteochondroma) these assholes point into the joint — this is why you have so many joint issues. You see this is young children. The osteochondroma looks more like an irregular mass. They tend to be treated with surgical excision.

Question 562

Supracondylar Spur (Avian Spur):

Answer 562

This is an Aunt Minnie, and normal variant. This is anosseous process, that usually does nothing, but can compress the median nerve if the Ligament of Ligament o f Struthers smashes it. Notice this thing points towards the joint, that is how you know it is not an osteochondroma. Also - it is not a Trevor Disease thing - because (1) of the characteristic location and (2) it is not originated from the epiphysis.

Question 563

P e rio s te a l Chondroma (J u x ta -C o r tic a l Chondroma):

Answer 563

When you see a lesion in the finger o f a kid think this. It’s a rare entity, o f cartilaginous origin. “Saucerization” o f the adjacent cortex with sclerotic periosteal reaction can be seen.

Question 564

O s teo fib ro u s D ysplasia

Answer 564

This is a benign lesion found exclusively in the tibia or fibula in children (10 and under - usually). It looks like an NOF , but is centered in the anterior tibia, and has associated anterior tibial bowing. It can occur with Adamantinoma, and the two cannot be differentiated with imaging

Question 565

When I say looks like NOF in the anterior tibia with anterior bowing

Answer 565

yo u say Osteofibrous Dysplasia.

Question 566

Dis ta l Fem ora l M e ta p h y s e a l Ir re g u la r ity (C o r tic a l Desmoid): overview

Answer 566

This is a lucency seen along the back o f the posteriomedial aspect o f the distal femoral metaphysis. If they show you a lateral knee xray, and there is an irregularity or lucency on the back o f the femur this is it. It’s often bilateral.

Question 567

Dis ta l Fem ora l M e ta p h y s e a l Ir re g u la r ity (C o r tic a l Desmoid): buzzwords

Answer 567

“Scoop like defect” with an | “irregular but intact cortex.”

Question 568

Dis ta l Fem ora l M e ta p h y s e a l Ir re g u la r ity (C o r tic a l Desmoid): treamtment

Answer 568

This is a total incidental finding and is a do n ’t touch lesion. Don’t biopsy it, Don’t MRI it. Just leave it alone. If you really want to know, it’s probably a chronic tug lesion from the adductor magnus.

Question 569

C a lc ium H y d ro x y a p a tite overview

Answer 569

Most pathologic calcification in the body is calcium hydroxyapatite, which is also the most abundant form o f calcium in bone. The calcium is deposited in tendons around the joint. The most common location for hydroxyapatite deposition is the shoulder. Specifically, the supraspinatus tendon is the most frequent site of calcification, usually at its insertion near the greater tuberosity. The longus colli muscle (the muscle anterior to atlas -> T3) is also a favorite location fo r multiple choice test writers. It may be primary (idiopathic) or secondary. Secondary causes worth knowing are: chronic renal disease, collagen-vascular disease, tumoral calcinosis and hypervitaminosis D.

Question 570

Calcium hydroxyapatite deposition disease

Answer 570

calcific tendinitis.

Question 571

Calcium hydroxyapatite deposition disease

Answer 571

calcific tendinitis.

Question 572

O s teo p o ik ilo s is :

Answer 572

It’s ju st a bunch o f bone islands. Usually in epiphyses (different from blastic mets or osteosarcoma mets). It can be inherited or sporadic but if you are forced to pick a pattern - I'd go with autosomal dominant.

Question 573

O s teo p o ik ilo s is : trivia

Answer 573

Osteopoikilosis tends to be joint centered (clustered around centered). Sclerotic mets will be all over the place. Sclerotic mets believe in nothing Lebowski.

Question 574

mers vs osteopoikilosis

Answer 574

Osteopoikilosis patients tend to be keloid formers.

Question 575

E ng elmarm ’s D is e as e overview

Answer 575

This is also known as progressive diaphyseal dysplasia or PDD. What you see is fusiform bony enlargement with sclerosis o f ; 5 j ; “ the long bones. This is a total zebra that begins in childhood.

Question 576

E ng elmarm ’s D is e as e things to know

Answer 576

* It's Bilateral an d Symmetric * It likes the long bones - usually shown in the tibia * I t s hot on bone scan * It can involve the skull — an d can cause optic nerve compression

Question 577

T h a la s s em ia overview

Answer 577

This is a defect in the hemoglobin chain (can be alpha or beta - major or minor). From the MSK Radiologist prospective, we are talking about “hair-on-end’ skulls, expansion o f the facial bones, “rodent faces,” expanded ribs “jail-bars” . It is frequently associated with extramedullary hematopoiesis.

Question 578

thalassemia sinuses

Answer 578

will obliterate sinuses

Question 579

sickle cell sinus

Answer 579

will not obliterate sinuses

Question 580

thalassemia lytic

Answer 580

Usually Asymptomatic

Question 581

thalassemia mixed (reparative)

Answer 581

Elevated Alkaline Phosphate. Fractures

Question 582

thalassemia sclerotic (latent inactive)

Answer 582

Elevated Hydroxyproline. More fractures. Sarcomas may develop.

Question 583

thalassemia sclerotic (latent inactive)

Answer 583

Elevated Hydroxyproline. More fractures. Sarcomas may develop.

Question 584

AVN of th e Hip Overview

Answer 584

Variety o f causes including Perthes in kids, sickle cell, Gaucher’s, steroid use e tc .... It can also be traumatic with femoral neck fractures (degree o f risk is related to degree o f displacement / disruption o f the retinacular vessels). AVN o f the hip typically involves the superior articular surface, beginning more anteriorly.

Question 585

AVN o f th e Hip: double line sign

Answer 585

Best seen on T2; inner bright line (granulation tissue), with outer dark line (sclerotic bone).

Question 586

AVN o f th e Hip: rim sign

Answer 586

Best seen on T2; high T2 signal line sandwiched between two low signal lines. This represents flu id between sclerotic borders o f an osteochondral fragment, and implies instability. (Stage III).

Question 587

AVN o f th e Hip: crescent sign

Answer 587

Seen on X-ray (optimally frog leg); Refers to a subchondral lucency seen most frequently in the anterolateral aspect of the proximal femoral head. It indicates imminent collapse.

Question 588

Plain film stages of osteonecrosis

Answer 588

``` o Zero = Normal o One = Normal x-ray, edema on MR o Two = Mixed Lytic / Sclerotic o Three = Crescent Sign, Articular Collapse, Joint Space Preserved o Four = Secondary Osteoarthritis ```

Question 589

P a g e t D is e a s e (O s te itis D e fo rm an s ) overivew

Answer 589

A relatively common condition that affects 4% o f people at 40, and 8% at 80 (actually 10%, but easier to remember 8%). M > F. Most people are asymptomatic. The pathophysiology o f Paget is not well understood.

Question 590

P a g e t D is e a s e (O s te itis D e fo rm an s ): phases

Answer 590

The bones go through three phases which progress from lytic to mixed to sclerotic (the latent inactive phase). The phrase “Wide Bones with Thick Trabecula” make you immediately say Pagets (nothing else really does that).

Question 591

P a g e t D is e a s e (O s te itis D e fo rm an s ): flavors

Answer 591

(1) Monostotic and (2) Polyostotic - with the poly subtype beingmuch more common (80-90%).

Question 592

P a g e t D is e a s e (O s te itis D e fo rm an s ): buzzwords/signs

Answer 592

•Blade of Grass Sign: Lucent leading edge in a long bone *Osteoporosis Circumscripta: Blade of Grass in the Skull •Picture Frame Vertebra: Cortex is thickened on all sides (Rugger Jersey is only superior and inferior cndplates) • Cotton Wool Bone: Thick disorganized trabeculae • Banana Fracture: Insufficiency fracture of a bowed soft bone (femur or tibia). *Tam O ’Shanter Sign: Thick Skull - with the frontal aspect “falling over the facial bones” *Saber Shin: Bowing of the tibia • Ivory Vertebra: This is a differential finding, including mets. Pagets tends to be expansile.

Question 593

P a g e t D is e a s e (O s te itis D e fo rm an s ): complications

Answer 593

Deafness is the most common complication. Spinal stenosis from cortical thickening is very characteristic. Additional complications include cortical stress fracture, cranial nerves paresis, CHF (high output), secondary hyperparathyroidism (10%), Secondary development of osteosarcoma (1%) - which is often highly resistant to treatment. As a piece o f ridiculous trivia - giant cell tumor can arise from Paget.

Question 594

P a g e t D is e a s e (O s te itis D e fo rm an s ): trivia

Answer 594

Of all the tumors to which Paget may devolve | to, Osteosarcoma is the Most Common.

Question 595

P a g e t D is e a s e (O s te itis D e fo rm an s ): total trivia

Answer 595

Paget bone is hypervascular and may be 5 degrees hotter than other bone (get your thermometer ready). Aik Phos will be elevated (up to 20x) in the reparative phase.

Question 596

P a g e t D is e a s e (O s te itis D e fo rm an s ): classic look

Answer 596

Expanded Bone Coarse or Thick Trabecular Pattern

Question 597

P a g e t D is e a s e (O s te itis D e fo rm an s ): skull

Answer 597

Large Areas of Osteolysis in the Frontal and Occipital Bones “Osteoporosis Circumscripta”, in the lytic phase. The skull will look “cotton wool” in the mixed phase. Thickened sclerotic appearance is a good chronic look. Involves BOTH inner and outer table (Fibrous Dysplasia favors the outer table) Tam O ’Shanter Sign: Skull sorta looks like one of those stupid hats with the frontal aspect “falling over the facial bones”

Question 598

P a g e t D is e a s e (O s te itis D e fo rm an s ): long bones

Answer 598

Advancing margin o f lucency from one end to the other is the so-called “blade o f grass” or “flame.” Will often spare the fibula, even in diffuse disease. Tibia Bowing “saber shin” is also classic.

Question 599

P a g e t D is e a s e (O s te itis D e fo rm an s ): pelvis

Answer 599

Most common bone involved. “Always” involves the iliopectineal line on the pelvic brim. Can cause advanced arthritis and acetabular protrusio. classic look on bone scan

Question 600

P a g e t D is e a s e (O s te itis D e fo rm an s ): spine

Answer 600

Cortical Thickening can cause a “picture frame sign” (same as osteopetrosis). Also can give you an ivory vertebral body.

Question 601

PAgets risks

Answer 601

The incidence increases with age (around 8% at age 80). It’s at increased risk for fracture, and has a 1% risk o f sarcoma degeneration (usually high grade). It’s shown two ways in the spine: (1) An enlarged “ ivory vertebrae”, (2) Picture frame vertebrae (sclerotic border) — with central lysis (mixed p h a se)

Question 602

Renal Osteodystrophy overview

Answer 602

The way it’s shown in the spine is the “Rugger Jersey Spine” - with sclerotic bands at the top and bottom o f the vertebral body. You could also have paraspinal soft tissue calcifications

Question 603

Renal Osteodystrophy sign

Answer 603

rugger jersey, top and botton only

Question 604

Osteopetrosis

Answer 604

This is a genetic disease with impaired osteoclastic resorption. You have thick cortical bone, with diminished marrow. On plain film or CT it can look like a Rugger Jersey Spine or Sandwich vertebra. On MR you are going to have loss o f the normal T1 bright marrow signal, so it will be T1 and T2 dark.

Question 605

H-shaped vertebra

Answer 605

is usually a buzzword for sickle cell, although it’s only seen in about 10% o f cases. It results from microvascular endplate infarct. If you see “H-Shaped vertebra,” the answer is sickle cell. If sickle cell isn ’t a choice the answer is Gauchers. Another tricky way to ask this is to say which o f the following causes “widening o f the disc space.” Widened disc space is another way o f describing a “ H Shape” without saying that.

Question 606

Pagets MRI

Answer 606

Lytic / Early Mixed: Heterogenous T2; T1 is isointense to muscle, with a “ speckled appearance” Late Mixed: Maintained fatty high T1 and T2 signals Sclerotic: Low signal on T1 and T2

Question 607

Pagets this vs that malignant vs active disease

Answer 607

* Both are T2 Bright and Will Enhance * Malignant Transformation will lose the Normal T1 signal (just like a cancer would) * Best Sequence fo r Distinguishing the two? T1 Pre Con

Question 608

Pagets nuclear medicine

Answer 608

The primary utility o f a bone scan is in defining the extent o f disease and to help assess response to treatment. The characteristic look for Paget is “Whole Bone Involvement.” For example, the entire vertebral body including the posterior elements, or the entire pelvis. The classic teaching is that Paget is hot on all three phases (although often decreased or normal in the sclerotic phase).

Question 609

Tibial Bowing overview

Answer 609

Most likely shown as an Aunt Minnie: NF-1 anterior with a fibular pseudoarthrosis, Rickets with wide growth plates, or Blounts tibia vara. Pagets can also cause this. The most likely pure trivia question is that physiologic bowing is smooth, lateral, an d occurs from 18 months - 2 years.

Question 610

Tibial bowing NF1

Answer 610

Anterior Lateral - Unilateral May be unilateral. May have hypoplastic fibula with pseudarthrosis.

Question 611

Tibial bowing foot deformities

Answer 611

Posterior

Question 612

Tibial bowing physiologic bowing

Answer 612

Lateral - Bilateral Symmetric Self limiting between 18 months and 2 years.

Question 613

Tibial bowing hypophosphatasia

Answer 613

Lateral Rickets in a newborn”

Question 614

Tibial bowing rickets

Answer 614

Lateral Fraying o f the metaphyses and widening o f the growth plates. Seen best in “fast growing bones” - knee, wrist

Question 615

Tibial bowing blount

Answer 615

Tibial Vara - Often asymmetric

Question 616

Tibial bowing osteogenesis imperfecta

Answer 616

Involves all long bones Early walking, Fat, black kid. Proximal tibia posteromedial physeal growth disturbance resulting in deformity

Question 617

Tibial bowing dwarfs

Answer 617

Short Limbs

Question 618

SOFT T IS S U E MASSES overview

Answer 618

Here is the simple part - only about 20-30% o f them can be accurately diagnosed on MRI. That’s because they are almost all T2 bright and enhance. This is actually good news for the purpose o f multiple choice, because you only need to learn the ones that d o n ’t behave like that - or are overwhelming likely due to epidemiological stats (which has to be provided for you - either directly “the patient is 65” or with clues - “arthritis = old” , “no arthritis = not old”).

Question 619

SOFT T IS S U E MASSES list

Answer 619

* MFH — Malignant Fibrous Histiocytoma aka - Pleomorphic Undifferentiated Sarcoma * Synovial Sarcoma * Lipoma, Atypical Lipoma, Liposarcoma * Hemangioma * Myxoma

Question 620

Malignant Fibrous Histiocytoma (MFH) name

Answer 620

Yes - they changed the name to Pleomorphic Undifferentiated Sarcoma "PUS.” However, I want you to continue to think o f this as MFH because it will help you remember some o f the imaging features.

Question 621

Malignant Fibrous Histiocytoma (MFH) overview

Answer 621

First, the generalizations — This is very common. It’s seen in old people. It’s seen in a central location (proximal arms and legs).

Question 622

Malignant Fibrous Histiocytoma (MFH) features

Answer 622

About h a lf the time it’s dark to intermediate on T2 (remember most soft tissue tumors are T2 bright). The way 1 remember this is the word “fibrous” - makes me think scar (which is dark).

Question 623

Malignant Fibrous Histiocytoma (MFH) gamesmanship

Answer 623

These things are often associated with spontaneous hemorrhage - they outgrow their blood supply. The history is often “old lady, stood up from a chair” - has a big proximal muscular hematoma — under that hematoma is the MFH.

Question 624

Malignant Fibrous Histiocytoma (MFH) trivia X2

Answer 624

Trivia: Bone infarcts can turn into MFH - ‘'sarcomatous transformation o f infarct" Trivia: Radiation is a risk factor.

Question 625

Synovial Sarcoma gamesmanship

Answer 625

They occur close to the joint (but not in the jo in t). To confuse the issue they may have secondary invasion into the joint (10%), however for the purpose o f multiple choice tests they “never involve the jo in t.” A common trick is to show an ultrasound o f the leg with looks like a Baker’s cyst - but the mother fucker is too complex - or has flow in it. *Not everything in the popliteal fossa is a Baker’s cyst - especially on multiple choice.

Question 626

Synovial Sarcoma ways to show

Answer 626

Besides the “not-a-Baker’s cyst” trick - there are 3 other ways to show this. (1) as the “trip le sign” , which is high, medium, and low signal all in the same mass (probably in the knee) on T2, (2) as the “ bowl of g ra p e s ” which is a bunch o f fluid -flu id levels in a mass (probably in the knee), or (3) as a plain x-ray with a soft tissue component and calcifications - this would be the least likely way to show it.

Question 627

Synovial Sarcoma trivia

Answer 627

* Most sarcomas d o n ’t attack bones; Synovial Sarcoma Can * Most sarcomas present as painless mass; Synovial Sarcomas Hurt * Soft tissue calcifications + Bone Erosions are highly suggestive * They are slow growing and small in size, often leading to people thinking they are B9. 90% have a translocation o f X -18. * Most common malignancy in teens/young adults o f the foot, ankle, and lower extremity

Question 628

“Ball-like tumor" in the extremity' o f a yo u n g adult

Answer 628

yo u say Synovial Sarcoma

Question 629

Soft Tissue Tumor in the Foot ” o f a yo u n g adult,

Answer 629

you say synovial sarcoma

Question 630

Baker’s Cyst

Answer 630

Baker’s Cyst MUST be located between the medial head of the gastrocnemius and the semimembranosus. If it’s NOT - you should think Synovial Sarcoma -and “next step” MRI.

Question 631

Baker’s Cyst

Answer 631

Baker’s Cyst MUST be located between the medial head of the gastrocnemius and the semimembranosus. If it’s NOT - you should think Synovial Sarcoma -and “next step” MRI.

Question 632

Lipoma vs Atypical Lipoma vs Liposarcoma overview

Answer 632

These exist on a spectrum, with Lipoma being totally benign, and Liposarcoma being a bad bad boy. A pearl is that, histologically, Atypical Lipoma behaves and looks ju st like a low grade Liposarcoma. It would be total horse-shit to ask you to tell those apart. It’s more likely the distinction will be either Lipoma vs Liposarcoma.

Question 633

Lipoma vs Atypical Lipoma vs Liposarcoma pearls

Answer 633

•Liposarcomas tend to be DEEP (retroperitoneum) ‘ Liposarcomas tend to be BIG ‘Lipomas tend to be Superficial

Question 634

Lipoma vs Atypical Lipoma vs Liposarcoma trivia

Answer 634

Myxoid Liposarcoma is the most common liposarcoma in patients < 20. They can be T2 Bright (expected), but T1 dark (confusing) - d o n 't call it a cyst. Also, d o n ’t call it a comeback (I’ve been here for years). They’ll need gad+

Question 635

Lipoma

Answer 635

Signal Intensity parallels fat on all sequences. Will Fat Sat Out No Sepations (or thin ones)

Question 636

Atypical lipoma/low grade liposarcoma

Answer 636

May have parts that are slightly darker (or brighter) than fat on T1. May incompletely fat sat Thick Chunky Septations

Question 637

high grade liposarcoma

Answer 637

May not even have fat (for the exam it will have some otherwise you can’t even tell for sure that it is a Liposarcoma) May incompletely fat sat (or not fat sat at all) Thick Nodular Complex Stuff Enhancing Components

Question 638

hemangioma tricks

Answer 638

• T2 bright (like most tumors) • Flow voids. They have to show you flow voids (buncha dark holes). • Hemangiomas don’t respect fascial boundaries - they will infiltrate into stuff (this is a somewhat unique feature). • Enhances Intensely - Duh - they are a vascular tumor • They can contain fat - and likely will on multiple choice.

Question 639

hemangioma next step

Answer 639

A great next step question would be to ask for a plain film. Why a plain film? phleboliths my friend — If they show you soft tissue phleboliths then hemangioma is the answer.

Question 640

Mazabraud syndrome

Answer 640

It’s a totally zebra syndrome - which makes it totally appropriate for an “ intermediate level exam.” It has 3 main findings: (1) Polyostotic Fibrous Dysplasia - which makes you ugly (2) Multiple Soft Tissue Myxomas (3) Difficulty finding a date to the prom — *see finding “ 1”

Question 641

Myxoma overview

Answer 641

If this shows up on the exam, it is almost certainly going to be shown in the setting o f Mazabraud Syndrome.

Question 642

Myxoma look like

Answer 642

They are T2 bright (like every tumor), but tend to be lower signal than muscle on T1 - which makes them sorta unique.

Question 643

CT v s MRI f o r L e s io n C h a r a c t e r i z a t i o n : CT is good for

Answer 643

-Occult Bone Destruction -Matrix and Mineralization — Example, better look at the lucent nidus of an osteoid osteoma.

Question 644

CT v s MRI f o r L e s io n C h a r a c t e r i z a t i o n : mr is good for

Answer 644

- Staging — specifically local extend and tumor spread. | - Follow up - to assess response to therapy.

Question 645

Osteosarcoma treatment

Answer 645

``` Chemo first (to kill micro m e ts ) , followed by wide excision ```

Question 646

Chondrosarcoma treatment

Answer 646

Usually ju st wide excision (they are usually low grade, and main concern is local recurrence).

Question 647

Giant Cell tumor treament

Answer 647

Because it extends to the articular surface usually requires arthroplasty.

Question 648

Ewings treatment

Answer 648

Both Chemo and Radiation, | followed by wide excision.

Question 649

Pigmented V illo n o d u la r Synovitis (PVNS) overview

Answer 649

PVNS is an uncommon benign neoplastic process that may involve the synovium o f the joint diffusely or focally. It can also affect the tendon sheath.

Question 650

Pigmented V illo n o d u la r Synovitis (PVNS) intra-articular disease

Answer 650

Basically, it’s Synovial Proliferation + Hemosiderin Deposition. The knee is by far the most common joint affected (65-80%). On plain film, features you will probably see are a joint effusion with or without marginal erosions. Osseous erosions with preservation o f the joint space and normal mineralization is typical. It is not possible to distinguish PVNS from synovial chondromatosis (see below) on plain film. MRI will be obvious with blooming on gradient echo, and this is the most likely way they will show this. Treatment is with complete synovectomy, although recurrence rate is 20-50%.

Question 651

Pigmented V illo n o d u la r Synovitis (PVNS) trivia

Answer 651

Unusual in kids, but when present is typically polyarticular.

Question 652

Pigmented V illo n o d u la r Synovitis (PVNS) giant cell tumor of the tendon sheath

Answer 652

Typically found in the hand (palmar tendons). Can cause erosions on the underlying bone. Will be soft tissue density, and be T1 and T2 dark (contrasted to a glomus tumor which is T1 dark, T2 bright, and will enhance uniformly).

Question 653

Prima ry Synovial Chondromatosis

Answer 653

``` There are both primary and secondary types; secondary being the result o f degenerative changes in the joint. The primary type is an extremely high yield topic. It is a metaplastic / true neoplastic process (not inflammatory) that results in the fonnation o f multiple cartilaginous nodules in the synovium o f joints, tendon sheaths, and bursea. These nodules will eventually progress to loose bodies. It usually affects one joint, and that one joint is usually the knee (70%). It is usually a person in their 40 ’s or 50’s. Joint bodies (which are usually multiple and uniform in size) may demonstrate the ring and arc calcification characteristic o f chondroid calcification. Treatment involves removal o f the loose bodies with or without synovectomy. ```

Question 654

PVNS quick

Answer 654

benign associated with hemarthrosis never calcifies

Question 655

Synovial chondromatosis quick

Answer 655

benign not associated with hemarthrosis may calcify

Question 656

S e conda ry Synovial Chondromatosis:

Answer 656

A lower yield topic than the primary type. This is secondary to degenerative change, and typically seen in an older patient. There will be extensive degenerative changes, and the fragments are usually fewer and larger when compared to the primary subtype.

Question 657

D ia b e tic M yone cros is:

Answer 657

This is basically infarction o f the muscle seen in poorly controlled type 1 diabetics. It almost always involves the thigh (80%), or calf (20%). MRI will show marked edema with enhancement and irregular regions o f muscle necrosis. You should NOT biopsy this: it delays recovery time and has a high complication rate.

Question 658

Lipoma A rb o re s c en s overview

Answer 658

This is a zebra that affects the synovial lining o f the joints and bursa. It's seen in late adulthood (50’s-70’s), with the most common location being the suprapatellar bursa o f the knee. Although it can develop in a normal knee, it’s often associated with OA, Chronic RA, or prior trauma. It’s usually unilateral. On MRI it’s going to behave like fat - Tl and T2 bright with response to fat saturation. This could also be shown on ultrasound with a “frond-like hyperechoic mass” and associated joint effusion.

Question 659

Lipoma A rb o re s c en s buzzword

Answer 659

“frond-like” deposition | o f fatty tissue.

Question 660

Lipoma A rb o re s c en s trick

Answer 660

sneaky trick is to show this on gradient - and have you pick up the chemical shift artifact at the fat-fluid interface.

Question 661

Bone Biopsy special considerations

Answer 661

Pelvis: Avoid crossing gluteal muscles (may be needed for reconstruction). Knee: Avoid the joint space via crossing suprapatellar bursa or other communicating bursae. Avoid crossing the quadriceps tendon unless it is involved. Shoulder: Avoid the posterior 2/3rd (axillary nerve courses post -> anterior, therefore a posterior resection will denervate the anterior 1/3).

Question 662

“Don’t Touch Lesions” Characteristically Benign Lesions that look Aggressive but are NOT - and should NOT be biopsied because o f possibly misleading pathology.

Answer 662

Myositis ossificans avulsion injury coritcal desmoid synovial herniation pit

Question 663

Myositis ossificans

Answer 663

Circumferential calcifications with a lucent center Can look scary on MRI if imaged early because o f edema, and avid enhancement

Question 664

Avulsion injury

Answer 664

Typical location near the pelvis Can have an aggressive periosteal reaction

Question 665

Cortical desmoid

Answer 665

Characteristic location on the posterior medial epicondyle o f the distal femur. Bilateral 30% o f the time. Can be hot on bone scan. NOT a desmoid (despite the name). It’s actually a tug lesion from the medial gastrocnemius and ADDuctor magnus.

Question 666

Cortical desmoid

Answer 666

Characteristic location on the posterior medial epicondyle o f the distal femur. Bilateral 30% o f the time. Can be hot on bone scan. NOT a desmoid (despite the name). It’s actually a tug lesion from the medial gastrocnemius and ADDuctor magnus.

Question 667

Synovial Herniation Pit | “Pitt’s Pit”

Answer 667

Characteristic location in the anterosuperior femoral neck. Lytic appearing lesion Associated with femoral acetabular syndrome (probably).

Question 668

Arthritis epidemiology

Answer 668

You can broadly categorize arthritis into 3 categories: Degenerative (OA, Neuropathic) Inflammatory (RA and Variants) Metabolic (Gout, CPPD)

Question 669

Osteoarthritis

Answer 669

most common cause. The pathogenesis is that you have mechanical breakdown (hard work) which leads to cartilage degeneration (fissures, micro-fractures) and fragmentation of subchondral bone (sclerosis and subchondral cysts). You get all the classic stuff, joint space narrowing (NOT symmetric), subchondral cysts, endplate changes, vacuum phenomenon, etc... The poster boy is the osteophyte.

Question 670

Neuropathic Joint

Answer 670

The way the case is classically shown is a bad joint followed by the reason for a bad joint (syringomyelia, spinal cord injury, etc...). A way to think about this is “osteoarthritis with a vengeance A The buzzword is “Surgical Like Margins.” Basically nothing else causes this kind of destruction. I like to describe the joints as a deformity, with debris, and dislocation, having dense subchondral bone, and destruction of the articular cortex. The classic scenario is a shoulder that looks like it’s been amputated, and then they show you a syrinx.

Question 671

Charcot Foot

Answer 671

The classic example of a diabetic neuropathic foot with the deformity, with debris, and dislocation, having dense subchondral bone, and destruction of the articular cortex - favoring the midfoot eventually causing a “rocker-bottom deformity” of the foot resulting from the collapse of the longitudinal arch.

Question 672

This vs That - Charot vs Infection

Answer 672

Diabetics get neuropathic feet and infections - so there can be overlap. To tell them apart you can look for the presence of an ulcer or sinus tract (that infers infection). Location is helpful - charcot prefers the midfoot (osteomyelitis prefers the pressure points of the forefoot - metatarsal heads, IP joints - and the posterior plantar aspect of the calcaneus).

Question 673

Erosive Osteoarthritis

Answer 673

(Inflammatory Osteoarthritis). The buzzword is “gull wing”, which describes the central erosions. It is seen in postmenopausal women and favors the DIP joints.

Question 674

Rheumatoid Arthritis overview

Answer 674

There is a ton o f trivia related to this disease. It’s not a disease o f bone production. Instead it is characterized by osteoporosis, soft tissue swelling, marginal erosions and uniform joint space narrowing. It’s often bilateral and symmetric. Classically spares the DIP joints (opposite o f erosive OA).

Question 675

Rheumatoid Arthritis trivia

Answer 675

The 5th Metatarsal head is the first spot in the foot

Question 676

Rheumatoid Arthritis in hte hand

Answer 676

Expect the PIP joints to be involved AFTER the MCP joints. The First CMC is classically spared (or is the last carpal to be involved). The first CMC should NOT be first. Obviously OA loves the first CMC so this is helpful in separating them. Psoriasis, on the other hand, also tends to make the first CMC go last.

Question 677

felty syndrome

Answer 677

RA > 10 years + Splenomegaly + Neutropenia

Question 678

caplan syndrome

Answer 678

RA + Pneumoconiosis

Question 679

Rheumatoid Variants

Answer 679

* Psoriatic Arthritis * Reiter’s syndrome (Reactive arthritis) * Ankylosing Spondylitis * Inflammatory Bowel Disease

Question 680

Psoriatic arthritis

Answer 680

This is seen in 30% o f patients with psoriasis. In almost all cases (90%) the skin findings come first, then you get the arthritis. As a point o f trivia, there is a strong correlation between involvement o f the nail and involvement o f the DIP joint. The classic description is “erosive change with bone proliferation (IP joints > MCP joints). The erosions start in the margins o f the joint and progress to involve the central portions (can lead to a “pencil sharpening” effect). The hands are the most commonly affected (second most common is the feet). Up to 40% o f cases will have SI joint involvement (asymmetric).

Question 681

Psoriatic arthritis buzzwords

Answer 681

“Fuzzy Appearance” to the bone around the joint (bone proliferation) Sausage Digit - whole digit has soft tissue swelling Ivory Phalanx - sclerosis and/or bone proliferation (most commonly the great toe) Pencil in Cup Deformities Ankylosis in Finger “Mouse Ears” Acro-osteolysis

Question 682

RA quick

Answer 682

symmetric proximal (favors MCP, carpals) osteoporosis can cause mutilans when severe

Question 683

psoriasis quick

Answer 683

asymmetric distal (favors ip joints) no osteoporosis bone proliferation (the form or periostitis) can cause mutilans when severe

Question 684

M u tila n s

Answer 684

``` Severe bone resorption leading to soft tissue “telescoping” collapse. Trivia: If you pulled on the patient’s fingers they would lengthen - but who would want to touch a patient ? Yuck! ```

Question 685

Reiter's overview

Answer 685

Apparently Reiter was a Nazi (killed a bunch o f people with typhus vaccine experiments). So, people try not to give him any credit for things (hence the name change to Reactive arthritis). Regardless o f what you call it, it’s a very similar situation to Psoriatic arthritis - both have bone proliferation, erosions, and asymmetric SI jo in t involvement. The difference is that Reiter’s is rare in the hands (tends to affect the feet more). Just remember Reiter’s favors things below the waist (like the penis = urethritis, and the foot).

Question 686

Reiter's triad

Answer 686

Urethritis Conjunctivitis Arthritis (Can't See or Climb a Tree to Pee on a Nazi named Reiter).

Question 687

Ank y los in g Spo n d y litis Overview

Answer 687

This disease favors the spine and SI joints. The classic buzzword is “bamboo spine” from the syndesmophytes flowing from adjacent vertebral bodies. Shiny comers is a buzzword, for early involvement. As you might imagine, these spines are susceptible to fracture in trauma. SI joint involvement is usually the first site (symmetric). The joint actually widens a little before it narrows. As a point o f trivia, these guys can have an upper lobe predominant interstitial lung disease, with small cystic spaces.

Question 688

Ank y los in g Spo n d y litis next step

Answer 688

Any significant Ank Spon / DISH + Even Minor Trauma = Whole Spine CT

Question 689

Random High Yield Topic: Ankylosing Spondylitis in the Hip

Answer 689

When the peripheral skeleton is involved in patient’s with Ank Spond, think about the shoulders and hips (hips more common). Hip involvement can be very disabling. Heterotopic Ossification tends to occur post hip replacement or revision. It occurs so much that they often get postoperative low dose radiation and NSAlDs to try as prophylactic therapy If they show you normal SI joints - then show you anything in the spine it’s not AS. It has to hit the SI joints first (especially on multiple choice).

Question 690

In flam m a to ry B ow e l D is e a s e (E n te ro p a th ic ) overview

Answer 690

Allegedly 20% o f patient’s with Crohns & UC have a chronic inflammatory arthritis.

Question 691

In flam m a to ry B ow e l D is e a s e (E n te ro p a th ic ) 2 types

Answer 691

(A): Axial Arthritis (favors SI joints and spine) - often unrelated to bowel disease (B): Peripheral Arthritis - this one varies depending on the severity o f the bowel disease.

Question 692

S I Jo int Involvement Patterns (Rheuma toid Variants) uniilateral

Answer 692

infection

Question 693

S I Jo int Involvement Patterns (Rheuma toid Variants) asymmetric

Answer 693

psoriasis or reiters

Question 694

S I Jo int Involvement Patterns (Rheuma toid Variants) symmetric

Answer 694

inflammatory bowel, AS

Question 695

Psoriatic arthritis quick

Answer 695

M=F asymmetric SI joint hands, feet, thoracolumbar spine

Question 696

reiters (reactive) quick

Answer 696

M>F asymmetric SI joint feet, lumbarspine, SI joint

Question 697

Ankylosing spondylitis quick

Answer 697

M>F symmetric SI joint SI joint, spine (whole thing)

Question 698

Gout overview

Answer 698

This is a crystal arthropathy from the deposition o f uric acid crystals in and around the joints. It’s almost always in a man over 40. The big toe is the classic location.

Question 699

Gout buzzwords/things to know

Answer 699

Earliest Sign = Joint Effusion Spares the Joint Space (until late in the disease); Juxtaarticular Erosions - away from the joint. “Punched out lytic lesions” “Overhanging Edges” Soft tissue tophi

Question 700

Gout MR

Answer 700

* Juxta-articular soft tissue mass (LOW ON T2). | * The tophus will typically enhance.

Question 701

Gout mimickers

Answer 701

``` “American Roentgen Ray Society Hooray” Amyloid RA (cystic) Reticular Histocytosis (the most rare) Sarcoid Hyperlipidemia ```

Question 702

CPPD overview

Answer 702

Calcium Pyrophosphate Dihydrate Disease is super common in old people. It often causes chondocalcinosis (although there are other causes). Synovitis + CPPD = “Pseudogout.” CPPD loves the triangular fibrocartilage o f the wrist, the peri-odontoid tissue, and intervertebral disks. Another important phrase is “degenerative change in an uncommon joint” - shoulder, elbow, patellofemoral joint, radiocarpal joint. Having said that, pyrophosphate arthropathy is most common at the knee.

Question 703

f you see isolated disease in the patellofemoral, radiocarpal, or talonavicular joint,

Answer 703

Think CPPD

Question 704

Classic look for CPPD

Answer 704

Hooked MCP Osteophytes with chondrocalcinosis in the TFCC is a classic took (although hemochromatosis can also look that way).

Question 705

CPPD can (and does commonly) cause

Answer 705

SLAC wrist by degenerating the SL Ligament.

Question 706

THIS vs THAT — OA vs CPPD

Answer 706

There are many overlapping features including joint space narrowing, subchondral sclerosis, subchondral cyst, and osteophyte formation. However, CPPD has some unique features, such as an “atypical joint distribution” - favoring compartments like the patellofemoral or radiocarpal. Subchondral cyst formation can be bigger than expected.

Question 707

H em o ch rom a to s is : overview

Answer 707

This iron overload disease also is known for calcium pyrophosphate deposition and resulting chondrocalcinosis. It has a similar distribution to CPPD (MCP joints). Both CPPD and Hemochromatosis will have “hooked osteophytes” at the MCP joint.

Question 708

H em o ch rom a to s is : trivia

Answer 708

As a point o f trivia, therapy for the systemic disease does NOT affect the arthritis.

Question 709

THIS v s THAT CPPD an d Hemochromatosis

Answer 709

Hemochromatosis has uniform joint space loss at ALL the MCP joints. CPPD favors the index and middle finger MCPs.

Question 710

“M ilw a u k e e S h o u ld er” overview

Answer 710

This is an apocalyptic destruction o f the shoulder (almost looks n e u ro p a th ic ) secondary to the demon mineral h y d ro x y ap a tite . The articular surface changes will be very advanced, and you have a lot o f intra-articular loose bodies. The humeral head will look like it needed the United Nations to delivery a binding resolution to keep the hydroxyapatite from fucking destroying it.

Question 711

“M ilw a u k e e S h o u ld er” classic history

Answer 711

Old women with a history o f trauma to that joint.

Question 712

Hyperparathyroidism overview

Answer 712

As you may remember from medical school, this can be primary or secondary, and its effects on calcium metabolism typically manifest in the bones. Here are your buzzwords: “Subperiosteal bone resorption' ’ o f the radial aspect o f the 2nd and 3rd fingers, rugger-jersey spine, brown tumors, and terminal tuft erosions.

Question 713

Hyperparathyroidism classic ways to show this

Answer 713

Superior an d inferior rib notching - bone resorption Resorption along the radial aspect o f the fin g e r s with brown tumors Tuft Resorption Rugger Jersey Spine Pelvis with Narrowing or “Constricting ” o f the fem o ra l necks, an d wide S I joints.

Question 714

Arthritis problem solving one or more - symmetric joint space narrowing - erosions

Answer 714

Inflammatory > one joint > infection Inflammatory > multiple joints > no bony proliferation and proximal distribution > RA Inflammatory > multiple joints > Bony proliferation and distal distribution > AS, psoriasis, reactive, inflammatory, bowel related

Question 715

Arthritis problem solving one or more - asymmetric joint space narrowing - osteophytes

Answer 715

Degenerative > typical joints (hands, knee) > OA Degenerative > atypical joint and age > post traumatic, gout or cppd, hemophilia Degenerative > atypical joint and age, severe or surgical destruction > neuropathic

Question 716

Spine Degenerative Change overview

Answer 716

In the real world it’s usually just multilevel degenerative change. But in multiple choice world you should be thinking about other things. Shiny comers with early AS, or flowing syndesmophytes with later AS. DISH with the bulky osteophytes sparing the disc space. The big bridging lateral osteophyte is classically shown for psoriatic arthritis.

Question 717

Cervical Spine: | Gamesmanship

Answer 717

Fusion: Either congenital (Klippel- Feil) or Juvenile RA. Erosions of the Dens: CPPD and RA famously do this. Bad Kyphosis = NF1

Question 718

DISH (Diffuse Idiopathic Skeletal H yperostosis

Answer 718

You see ossification o f the anterior longitudinal ligament involving more than 4 levels with sparing o f the disc spaces, you say DISH. The thoracic spine is most commonly used. These guys often have bony proliferation at pelvis, ischial tuberosities, trochanters, and iliac crests. There is no sacroiliitis (helps you differentiate from AS).

Question 719

OPLL (Ossification of the Posterior Longitudinal Ligament):

Answer 719

This is an ossification o f the posterior longitudinal ligament. It is associated with DISH, ossification o f the ligamentum flavum, and Ankylosing Spondylitis. It favors the cervical spine o f old Asian men. It can cause spinal canal stenosis, and can lead to cord injury after minor trauma. A key point is that it’s bad news in the cervical spine (where it is most common); in the thoracic spine it is usually asymptomatic.

Question 720

Destructive Spondyloarthropathy

Answer 720

This is associated with patients on renal dialysis (for at least 2 years), and it most commonly affects the C-spine. It looks like bad degenerative changes or CPPD. Amyloid deposition is supposedly why it happens.

Question 721

Systemic Lupus Erythematosus arhtritis

Answer 721

The Aunt Minnie look is reducible deformity of joints without articular erosions. Joint space narrowing and erosions are uncommon findings. They can show you the hands with ulnar subluxations at the MCPs on Norgaard view, then they reduce on AP (because the hands are flat). This ligamentous laxity also increases risk of patellar dislocations.

Question 722

Jaccoud’s Arthropathy

Answer 722

This is very similar to SLE in the hand (people often say them together). You have non erosive arthropathy with ulnar deviation of the 2nd-5th fingers at the MCP joint. The history is post rheumatic fever.

Question 723

Mixed Connective Tissue Disease

Answer 723

One unique feature is that it is positive for some antibody Ribonucleoprotein (RNP) - and therefore serology is essential to the diagnosis.

Question 724

Juvenile Idiopathic Arthritis overview

Answer 724

This occurs before age 16 (by definition). What you see is a washed out hand that has a proximal distribution (carpals are jacked), and is ankylosed (premature fusion of growth plates). Serology is often negative (85%). In the knees, you see enlargement of the epiphyses and widened intercondylar notch - similar to findings in hemophilia.

Question 725

Juvenile Idiopathic Arthritis buzzword

Answer 725

“Epiphyseal Overgrowth” Widened intercondylar notch

Question 726

Amyloid Arthropathy

Answer 726

This is seen with patients on dialysis (less commonly in patients with chronic inflammation such as RA). The pattern of destruction can be severe - similar to septic arthritis or neuropathic spondyloarthropathy. The distribution is key, with bilateral involvement of the shoulders, hips, carpals, and knees being typical. Carpal tunnel syndrome is a common clinical manifestation. The joint space is typically preserved until later in the disease. When associated with dialysis, it’s rare before 5 years of treatment, but very common after 10 years (80%).

Question 727

Pituitary Gigantism

Answer 727

If they happen to show you x-rays of Andre the Giant, look for “widening of the joint space in an adult hip” - can be a classic buzzword. Late in the game, the cartilage will actually outgrow its blood supply and collapse, leading to early onset osteoarthritis. The formation of endochondral bone at existing chondro-osseous junctions results in widening of osseous structure.

Question 728

Bone marrow consists o f three components

Answer 728

(1) Trabecular Bone - the support structure, (2) Red Marrow - for making blood, and (3) Yellow Marrow - f a t for a purpose unknown at this time.

Question 729

Marrow Conversion:

Answer 729

The basic rules are that yellow marrow increases with age, in a predictable and progressive way. This is usually completed by the mid 20s. You are bom with all red marrow, and the conversion o f red to yellow occurs from the extremities to the axial skeleton (feet and hands first). Within each long bone the progression occurs epiphyses / apophyses first -> diaphysis -> followed by the distal metaphysis , and finally the proximal metaphysis. Red marrow can be found in the humeral heads and femoral heads as a normal variant in adults.

Question 730

Yellow marrow expands

Answer 730

out from the middle

Question 731

Asa child you have diffuse

Answer 731

red marrow except for ossified epiphyses and apophyses

Question 732

As adults you have yellow marrow

Answer 732

everywhere except in the axial skeleton and proximal metaphyses of proximal long bones

Question 733

What is the normal pattern o f conversion ?

Answer 733

The epiphyses convert to fatty marrow almost immediately after ossification. Distal then proceeds medial / proximal (diaphysis first, then metaphysis).

Question 734

What is the normal pattern o f Reconversion ?

Answer 734

The pattern o f reconversion: This occurs in the reverse order o f normal marrow conversion, beginning in the axial skeleton and heading peripheral. The last to go are the more distal long bones. Typically, the epiphyses are spared unless the hematopoietic demand is very high. spine > flat bones > long bone metaphysis > long bone diaphysis > long bone epiphyses

Question 735

What areas are spared / normal variants?

Answer 735

Patchy areas o f red marrow may be seen in the proximal femoral metaphysis o f teenagers. Distal femoral sparing is seen in teenagers and menstruating women.

Question 736

Leukemia overview

Answer 736

Proliferation o f leukemic cells results in replacement o f red marrow. Marrow will look darker than muscle (and normal disks) on T l. On STIR, marrow may be brighter than muscle because o f the increased water content. T2 is variable, often looking like diffuse red marrow.

Question 737

Leukemia shown in 2 ways

Answer 737

(1) Lucent metaphyseal bands in a kid (2) Tl-weighted MRI showing marrow darker than adjacent disks and muscle. Remember that Red Marrow is still 40% fat and should be brighter than muscle on T l.

Question 738

Most infdtrative conditions affect the marrow diffusely. The exceptions are

Answer 738

multiple myeloma, which has a predilection fo r focal “speckled ” deposits, and Waldenstrom's macroglobulinemia, which causes infarcts.

Question 739

C hlo roma (G ra n u lo c y tic S a rcom a )

Answer 739

Just say “destructive mass in a bone o f a leukemia patient. ” It’s some kind o f colloid tumor.

Question 740

Anisotropy overview

Answer 740

The most common and most problematic issues with ultrasounding tendons is this thing called “anisotropy.” The tendon is normally hyperechoic, but if you look at it when it’s NOT perpendicular to the sound beam it can look hypoechoic (injured?).

Question 741

Anisotropy pain

Answer 741

"Supraspinatus tendon - as it curves along the contours o f the humeral head *Long Head o f the Biceps - In the bicipital groove

Question 742

US Tears

Answer 742

The tendon is usually hyperechoic. Focal hypoechoic areas are tears. It can be really tricky to tell if it’s partial or complete (that’s what MRI is for).

Question 743

US Tenosynovitis

Answer 743

If they show it on ultrasound, you are looking for increased fluid within the tendon sheath. You could also see associated peritendinous subcutaneous hyperemia on Doppler.

Question 744

Tenosynovitis =

Answer 744

increased fluid in the tendon sheath

Question 745

US Plantar Fasciitis overview

Answer 745

This is another pathology that lends itself to a “what is it ? ” type o f ultrasound question. Hopefully, they at least tell you this is the foot (they could label the calcaneus). The finding will be thickening o f the plantar fascia (greater than 4 mm), with loss o f the normal fibrillar pattern. If you see calipers on the plantar fascia - this is going to be the answer.

Question 746

US Plantar Fasciitis trivia

Answer 746

Most commonly involves the central band (there are 3 bands - people who do n ’t know anatomy think there are two).

Question 747

Calcific Tendonitis US

Answer 747

this is very common and related to hydroxyapatite. The most common site is the supraspinatus tendon, near its insertion. It will shadow ju st like a stone in the GB.

Question 748

Calcific Tendonitis =

Answer 748

shadowing calcification in the classic locations (supraspinatus)

Question 749

Hip procedure steps

Answer 749

( l ) Mark the femoral artery. (2) Internally rotate the hip (slightly) to localize the femoral head-neck junction (your target). (3) Clean and numb the skin. (4) Advance a 20-22 gauge spinal needle into the joint - straight down on the superior head neck junction. (5) Inject a small amount o f contrast to confirm position. Contrast should flow away from the tip. If the contrast just stays there it’s not in the capsule. (6) Put the rest o f the contrast in.

Question 750

Hip procedures trivia 1

Answer 750

Capsule is widest at the head-neck junction.

Question 751

Hip procedures trivia 2

Answer 751

The cocktail injected is around 14 cc total (4 cc Lidocaine, 10 cc Visipaque, and only about 0.1 cc Gd).

Question 752

Shoulder procedures steps

Answer 752

(1) Supinate the hand (externally rotate the shoulder) (2) Clean and numb the skin. (3) Advance a 20-22 gauge spinal needle into the joint - straight down on the junction between the middle and inferior third o f the humeral head - 2 mm inside the cortex. (4) Once you strike bone, pull back 1 mm and turn the bevel towards the humeral head - this should drop into the joint (5) Inject a small amount o f contrast to confirm position. Contrast should flow away from the tip. If the contrast just stays there it’s not in a space. (6) Put the rest o f the contrast in.

Question 753

Shoulders procedures trivia

Answer 753

The cocktail injected is around 12cc total (4cc Lidocaine, 8cc Visipaque, and only about 0.1 cc Gd).

Question 754

Patient is allergic to (has a phobia of) Gd, but needs an arthrogram?

Answer 754

You could try a CT Arthrogram. So - not Gad, ju st Visipaque and Lidocaine.

Question 755

Patient is allergic to (has a phobia of) CT Contrast (Visi or Omni), but needs a steroid joint injection?

Answer 755

You can inject air into the joint (instead o f visi) to confirm placement - then put the steroid in.

Question 756

Patient is allergic to (has a phobia of) CT Contrast (Visi or Omni), but needs an arthrogram ?

Answer 756

This situation is different. You c an’t inject air because you will end up with a big blooming mess on MR. CT isn’t an option either - because obviously you need the CT Contrast or it’s not an arthrogram. Your only choices would be to either (1) pre medicate them, or (2) use the force (trust your feelings...) and hope you can get in the joint without confirming positioning with fluoro.