MSK - Trauma Flashcards
Where should contrast be injected in MR arthrogram in suspected triangular fibrocardilage tear?
Dorsal approach to radiocarpal compartment
If contrast leaks from radiocarpal compartment to the distal radioulnar compartment - this confirms presence of a tear
What is the arcuate sign?
The arcuate sign is the elliptical shaped avulsed bony fragment adjacent to the fibular styloid process representing an avulsion fracture of the fibular styloid.
The arcuate ligament attaches to fibular styloid and together with the LCL and lateral joint capsule forms the Arcuate complex
What is O’Donoghues triad?
MMA
Happens during football injuries where there is valgus stress on a flexed knee (known as clip and pivot shift injury)
- MCL injury (shift)
- ACL injury (pivot)
- Medial meniscus injury (remember meniscus is attached to MCL)
((lateral meniscus injuries are actually more common than medial in this type of injury))
What are pelligrini stieda lesions?
Where are they located?
Located within Medical collateral ligament
Tiny fragments of calcification that have formed in MCL following trauma
Seen superomedially to femoral condyle
- Appears weeks after injury
- Most patients are asymptommatic
What is Sinding-Larsen-Johannsen disease?
Affects 10 - 15 year olds
Affects proximal end of patellar tendon as it inserts into inferior patella
- patellar tendon thickening
- -possible stranding in hoffas fat pad*
Similar to osgood schlaters - fragmentation at patellar tendon insertion at tibial tuberosity
Below images demonstrates both
Different avascular necrosis names
Injury to what wrist ligament causes midcarpal dislocations?
Lunotriquetral ligament
Lunate dislocation is a result of dorsal radiolunate injury
Injury to capitolunate ligament results in perilunate dislocations
What is a reverse Segond fracture?
RPM
Avulsion of the medial tibial plateau (after external rotation injury)
Associated with:
-PCL injury
-Medial meniscus tear
What is a segond fracture?
Avulsion of the lateral tibial plateau
Associated with ACL injury
What is most common type of ankle injury?
Supination external rotation - results in low fibular fracture (sometimes medial malleolar fracture)
Which part of scaphoid is most susceptible to AVN?
What is earliest sign of AVN?
Blood flow to scaphid is retrograde distal to proximal
Therefore proximal scaphoid is most susceptible
Most common site of fracture is the waist
First sign of AVN is sclerosis
What is a sign of scapholunate ligament disruption/tear?
Assocaited with 30% of distal radius fractures
A gap of >3mm between the scaphoid and lunate
Terry thomas sign
SLAC and SNAC wrist
What are they and whats difference?
SLAC
Scapholunate advanced collapse due to:
- injury (scapholunate dislocation)
- CPPD degeneration
- The scapholunate ligament prevents rotation of the scaphoid during flexion*
- When ligament is damaged:*
- *-scaphoid will tilt**
-radioscaphoid space will narrow
-capitate will migrate proximally
SLAC and SNAC are commonest causes of wrist arthritis
SNAC of wrist
What is it?
Scaphoid Non union advanced collapse
There is scapholunate dislocation due to scaphoid fracture
Results in significant radioscaphoid arthritis
What is DISI and VISI?
It has to do with issue of the scapholunate ligament and scaphoid and lunate
The scapholunate ligament has 3 parts:
-dorsal (lunate like to tilt dorsally
-volar (scaphoid likes to tilt volar)
-middle
With a ligament injury the carpal bones want to move
DISI (Dorsal intercalated segemental instability)
Essentially dorsiflextion instability
Due to a RADIAL SIDED injury:
- -scaphoid fracture*
- -distal radius fracture*
- -radius malunion*
- -ligamentous injury*
- Injury of the scapholunate causing dorsal tilt of the lunate (no support from scaphoid as its ligament is damaged)*
- scapholunate angle on the lateral will be >60 (sign of scapholunate dislocation)
-capitalunate angle on lateral >30 (capitate will be displaced posteriorly compared to radius)
As a result of trauma usually
VISI
What is it?
Volar flexion injury
MUCH LESS common than DISI
Due to injury on the ULNAR SIDE:
- can be found in uninjured wrists however and often seen as a normal variant in patients with wrist laxity
- Narrowing of the scapholunate angle (<30) with VOLAR tilt of both the SCAPHOID and LUNATE*
- Dorsal tilt of the CAPITATE and HAMATE*
Lunate and perilunate dislocations
What fracture is peri-lunate associated with?
In peri-lunate dislocate the lunate stays PUT
Perilunate is associated with SCAPHOID fracture
Triangular fibrocartilage complex
Where is is located?
What is function?
A complex of ligaments that supports the wrist
Located between ulna, lunate and triquetrum
Shape can vary depending on the ulnar variance
Positive ulnar variance: thinner and arc shaped TFC
Negative ulnar variance: thicker and shorter with more horizontal lie
Triangular fibrocartilage injury
What symptoms will patient present with?
Traumatic injuries are symptommatic whereas degeneration is asymptommatic (tends to be ass with positive ulnar variation)
Presenting features include:
- -ulnar sided wrist pain*
- -pain on pronation and supination*
- -pain on ulnar deviation*
Look for ulnar styloid fracture.
Has alot of potential assoiated ligamentous injuries e.g. radioulnar ligament, lunotriquetral ligaments
TFC injury will appear as high T2 signal extending to surface of ulna
TFC degeneration are high T2 but WONT extend to the joint
Healing
Ulnar side of TFC (medial) is vascular so more likely to heal and surgery is an option
Central tears are avascular and less likely to heal
What is ulnar impaction syndrome?
Essential where there is positive ulnar variance and the ulna smashes into the lunate causing degeneration and TFC injury
- subchondral sclerosis cysts of ulna and lunate
- Can be a result of distal radius fracture with shortening*
What is Kienbocks?
AVN of the lunate in people aged 20-40’s
Assocaited with NEGATIVE ulnar variance
-Signal drop out on T1
What is a Barton fracture?
This is a type of intraarticular distal radial fracture
Can be either dorsal or volar extension to the joint
Associated with radiocarpal joint dislocation
Dorsal angulation
What is considered normal angle on the lateral view?
Normal angle is 11 degrees
What is contained within carpal tunnel?
Defined by 4 bony prominence: PSHT
- pisiform
- scaphoid tubercle
- hamate hook
- trapezium tubercle
Within tunnel - 10 things
- Flexor pollicis longus (FPL) x1*
- Flexor digitorum superficialis (FDS) x 4*
- Flexor digitorum profundus (FDP) x 4*
- Median nerve*
Where does DeQuervans tenosynovitis affect?
Classically seen in new mum holding a baby
Repetitive strain injury
Affected tendons
- Extensor pollicis brevis (EPB)*
- Abductor pollicis longus (APL)*
Intersection Syndrome
Seen in rowers
Affects the extensor carpi radialis, brevis and longus
Due to first extensor tendon intersecting the second
Small fractures summary
Bennetts
Base of thumb fracture
NOT comminuted
Rolandos
Base of thumb fracture
Comminuted
Gamekeepers Thumb
Fracture at base of first phalanx thumb
Assocaited with ulnar collateral ligament disruption
DONT do stress views
Monteggia vs Galeazzi fracture
MUGR
(Monteggia Ulnar Galeazzi Radius)
Monteggia
Proximal ulna fracture with anterior dislocation of the radial head
Galeazzi
Radial shaft fracture with anterior dislocation of the distal ulna
What is cubital tunnel syndrome?
Compression of the ulnar nerve in a tunnel on the inside of the elbow
A common cause is an accessory aconeus
- Aconeus is normally located on the radial side (lateral)*
- An accessory aconeus can also be seen on the medial side and compress on the ulnar nerve*
- -will orgiginate at medial epicondyle and insert into olecranon*
Lateral epicondylitis vs medial
Lateral = tennis elbow
extensor carpii radialis brevis
Medial = golfers elbow (less common)
What fractures associated with elbow disloation?
Coronoid process
Radial head
External vs internal rotator cuff impingement
Whats the difference?
External
Otherwise known as subacromial impingement
Causes:
- -Hooked acromion (Type 3 Acromion)*
- -Subacromial osteophyte*
- -Subcoracoid impingement (of the subscapulars tendon)*
Internal
Inpingement of rotator cuff at internal deep part at glenoid labrum and humeral head
- Posterior superior (site on glenoid where impingement occurs) - occurs in abduction external rotation where juction of supra and infra tendons contact posterior superior glenoid*
- Anterior superior - biceps and subscap hit anterior superior glenoid rim (arm extended horiz in abduction)*
What is a SLAP tear?
Superior labral anterior posterior tear
Tears involve the superior glenoid labrum where long head of biceps inserts (can extend into tendon)
- can be seen after fall onto outstretched arm
- -seen in swimmers*
NOT associated with instability
What happens in subluxation of the biceps tendon?
Subscapularis extends to attach onto the lesser tuberosity
The transverse humeral ligament is an extension of fibres from subscapularis -
Transverse humeral ligament covers the bicipital groove keeping long head of biceps tendon in
When there is injury to subscapularis = the transverse ligament is disrupted resulting in medial dislocation/subluxation of the long head of biceps
HAGL
What does it stand for?
How does it happen?
Humeral avulsion glenohumeral ligament
- Avulsion of the inferior glenohumeral ligament due to anterior dislocation of the shoulder*
- Can be associated with a bony avulsion fracture of humeral neck*
Avulsion fractures of pelvic bones
What tendons attach where?
Ilioptibial Band syndrome
Repetitive stress injury seen in runners
Pain over greater trochater or lateral knee joint (1-2cm above lateral joint line)
- Key finding is fluid on both sides of the iliotibial band (between bone and tendon)*
- Adjacent to lateral femoral condyle*
Particle Disease
What is it?
Also known as Aggressive Granulomatosis
Occurs post joint replacement down the line 1-5 years
Anything that causes extra wear in the joint can induce this e.g poorly placed
Where metal particles from the prosthesis can cause an inflammatory response
- -Joint effusion*
- -Lytic areas around the prosthesis*
- -Can be seen around screw holes*
What is typical sign seen in sacral insufficiency fractures?
Honda sign
Due to uptake on Bone scan or seen
What Arcuate sign?
Avulsion of the proximal fibula
At the insertion of arcuate ligament complex
Associated with PCL injury
Meniscal tears - Longitudinal Types?
Happen after rotatory truma to the knee
Longitudinally Orientated Tears
Two types:
- Horizontal - perpendicular to tibial plateau (like 2 slices of bread on top of eachother)*
- Vertical - perpendicular to tibial plateau. Top to bottom type tear*
Radial Meniscal Tears
Radial tears can progress to parrot beak radial tear
Often not repaired as are in the AVASCULAR zone and low likelihood of healing
Buckethandle Tears
Displaced longitudinal (vertical) meniscal tear
Most commonly in medial meniscus and associated with ACL injury
Can have appearance of a double PCL on saggital of medial meniscus
What is discoid meniscus and associations?
Where meniscus is a full disc instead of a C shape
Associated with increased risk of tear
Paeds patient with meniscal tear think this!!
Maisonneuve Fracture
Fracture proximal fibula and unstable ankle injury - tibiofibular ligament/deltoid ligament and medial malleolar fracture
Will see widening of mortise
3 types of base of 5th metatarsal fracture?
Stress
Jones
Avulsion
Lisfranc Injury
What are signs?
Ligamentous complex is an important stabiliser of the midfoot
The Lisfranc ligament connects the medial cunieform to the 2nd metatarsal base
Injury Mechanisms
- -direct crush injury*
- -forced plantar flexion*
Radiology signs
>2mm space between bases of 1st and 2nd metatarsals on plain film
Can have associated fracture of 2nd metacarpal base (fleck sign)
Weight bearing views are important if in doubt - CT is best
What is sinus tarsi syndrome?
Diagnosis NOT to be made in setting of trauma
Seen in:
-dancers/voleyball players/basketball/overweight people/
**Pain and tenderness over lateral side of the hindfoot**
Feeling of unsteadiness on weight bearing (Sinus tarsi is important in proprioception)
Caused by haemorrhage or inflammation within the synovial recesses of the sinus tarsi with or without tears of associated ligaments
On MRI there will be fluid or scar tissue within fat of sinus tarsi +/- ligament injury
What is tarsal tunnel syndrome?
Pain in distribution of posterior tibial nerve distribution (first 3 toes)
Due to compression of posterior tibial nerve as it passes through the tarsal tunnel (behind medial malleolus)
Mass lesions can also cause compression in the tarsal tunnel
What is Haglunds deformity?
Bony enlargement at the posterior super aspect of the calcaneus
The deformity leads to retrocalcaneal bursitis
Os Trigonum syndrome
What is it?
Who does it occur in?
Posterior ankle pain caused by wedging of soft tissue between os trigonum and posterior talus and calcaneus. Happens in EXTREME plantar flexion
- **Flexor hallucis longus can become entrapped***
- Seen in Ballet Dancers*
What is classic cause of ‘achilles tendon rupture but can still plantar flex?
Plantaris rupture (seen in tennis players on forced dorsiflexion)
Plantaris tendon is ABSENT in 10% of population
MRI - seen as fluid collection between medial head of gastrocnemius and soleus
What is a clip injury?
What is ruptured?
High T2 signal to the anterior aspect of the lateral femoral condyle and lateral tibial plateau with an anterior cruciate ligament and medial collateral ligament tear
ACL vs PCL anatomy
PALM
ACL is lateral to medial (ACL attaches to posterior part of lateral condyle of femur from Anterior intercondylar area of tibia)
APML
PCL is medial to lateral (anterior part of medial femoral condyle to posterior part of intercondylar area of tibia
Ankle fracture injury types
Clip and Pivot Shift summary
SI joint fracture and pubic symphysis/rami frature
What fracture type is it?
What is it assc with?
Open book fracture
Unstable fracture
Due to AP force on the pelvis
What is Malgaigne fracture?
Unilateral pelvic fractures that are unstable
SI joint + ipsilateral pubic rami
Ilioischial line = posterior or anterior column border of acetabulum?
Posterior
Rockwood classification
What is it for?
What grade constitutes rupture of CC and AC ligament?
Grades III - IV imply soft tissue/muscle injury of deltoid
