Knee Fx

Question 1

imaging

Arthrogram:

Answer 1

Great for looking for tears in soft tissue inside and around a joint (cartilage/ menisci, labrum, tendons, ligaments, etc), often combined with CT/MRI

Question 2

imaging

PET scan and bone scan

Answer 2

Used for monitoring all bones at once to see if there are multiple lesions; images are typically not very specific; PET can be used in a specific location or entire body and often combined with CT or MRI

PET scan monitors general metabolic activity with a tracer

Bone scan monitors osteoblast activity with a tracer (new bone formation)

Question 3

MRI and CT

Answer 3

MRI : Great for soft tissue and bone changes (infection, inflammation, necrosis, etc); taken in slices like CT; can be distorted by metal

CT : Great for seeing bone and alignment issues in multiple slices; can result in 3-D reconstruction; not great for soft tissue

Question 4

Answer 4

Question 5

Answer 5

Question 6

Knee: Osteochondritis Dissecans (OCD)

etiology and common complaints

Answer 6

Etiology:
Subchondral necrosis and collapse with cartilage damage (AVN but on a smaller scale)
Hereditary, traumatic, or vascular in nature

Common symptoms/complaints:
Knee pain with locking/ popping

Question 7

Knee: Osteochondritis dissecans

PE and test

Answer 7

Physical Exam:
Localize joint line tenderness
Occasionally will have effusion
Occasionally will have popping

Tests: start with X-Rays (knee – notch view) but MRI is needed to determine severity

Question 8

Knee: Osteochondritis dissecans

Tx and pearls

Answer 8

Treatment:
Kids: more conservative tx like rest, cast, NWB x several months
Adults: stable – weight bearing restrictions, unstable surgical repair – drilling, screw fixation, resurfacing, joint replacement
Both require surgical removal if there is a loose body in the joint

Pearls:
Most common location of OCD in the knee is the posterior lateral aspect of the medial femoral condyle (70%), capitellum of humerus, talus

Question 9

Knee: Bipartite Patella

etiology anf complaints

Answer 9

Etiology: lack of fusion of patella at growth area; results in patella that is in multiple pieces
Typically, only hurts if there is repetitive trauma but patient cannot recall a specific injury
Incidental finding on radiograph

Common symptoms/ complaints:
Typically, asymptomatic
Sometimes pain resulting from trauma

Question 10

Knee: Bipartite Patella

PE and tests

Answer 10

Physical Exam:
TTP over patella if inflamed; otherwise, unremarkable

Tests:
X-rays: edges will often not be as sharp as fractures
MRI can help to visualize inflammation

Question 11

Knee: Bipartite Patella

Tx and pearls

Answer 11

Treatment:
Rest
Immobilization
Physical Therapy
Sometimes fixation is needed (treat it like a fracture)

Pearls:
Bilateral in 50% of patients with the disease

Question 12

Knee: Patellar Instability

etiology and presentation

Answer 12

Etiology:
Medial or lateral subluxation or dislocation of patella; often related to loose or torn retinaculum (MPFL) or muscle weakness

Presentation:
Depends on severity of injury
Pain, swelling, “kneecap popped out of socket”
Non-contact twisting injury w/ knee & foot externally rotated

Question 13

Knee: Patellar Instability

PE and Dx

Answer 13

PE:
Chronic: sometimes can manipulate patella to sublux – patellar translation

Acute: Traumatic Effusion
If dislocated, it will be visible
TTP at medial* or lateral edge of patella

Diagnosis:
X-rays and MRI to see location, inflammation, loose bodies, MPFL tears

Question 14

Knee: Patellar Instability

Tx

Answer 14

Treatment:
Depends on severity
Obviously needs to be reduced if dislocated
PT for quad strengthening – 6 weeks
Rest

Surgical repair
MPFL repair/reconstruction
Tibial tubercle distalization

Question 15

Knee: Patellar Tendon Rupture/ Quad Rupture

Etiology and complaints

Answer 15

Etiology:
Tension overload during activity (flexed or overload of extensor mechanism)
Quad tendon 2x more likely than patellar ligament rupture
Risk factors: previous injury, steroid injection, DM, SLE, RA, renal disease (weakening of collagen)

Common symptoms/ complaints:
Felt/hear a pop and noticed immediate visible abnormality
“Jumper’s knee” – sudden quad contraction with knee flexed

Question 16

Knee: Patellar Tendon Rupture/Quad Rupture

PE and Tests

Answer 16

Physical Exam:
Patella – difficulty w/ knee flexion, patella alta
Quad – difficulty with straight leg raise, can’t extend knee, sulcus sign noted, patella baja
Possibly will have swelling and bruising
Hemarthrosis

Tests:
X-rays will show abnormal patellar positioning
MRI confirms tendon rupture – complete vs partial

Question 17

Knee: Patellar Tendon Rupture/ Quad Rupture

PE and Tests

Answer 17

Treatment:
Immobilization in KI
Conservative tx w/ intact extensor mechanism
Operative: surgical repair of tendon – suture anchor, end to end, graft
Pearls:
Quad more often in over 40 y.o. patients
Patellar more often in under 40 y.o. patients (30-40yo)
Complications: knee stiffness/re-tear

Question 18

Knee: Prepatellar Bursitis

Etiology and common complaints

Answer 18

Etiology:
Bursa anterior to the patella becomes inflamed due to overuse or direct trauma
Commonly in patient’s who do excessive kneeling – concrete, flooring
20% septic bursitis
“Housemaid’s knee”

Common symptoms/ complaints:
Pain, anterior swelling, mostly normal ROM

Question 19

Knee: Prepatellar Bursitis

PE and tests

Answer 19

Physical Exam:
Prepatellar edema
Fluctuance, +/- TTP over patella
Near full AROM
Tests:
Aspiration if concern for septic pre-patellar bursitis
X-Ray knee r/o joint effusion

Question 20

Knee: Prepatellar Bursitis

Tx

Answer 20

Treatment:
Rest, NSAIDs, aspiration followed by compression – steroids controversial
Occasionally will need surgical excision of the bursa

Question 21

Knee: Pes Anserine Bursitis

Etiology and common complaints

Answer 21

Etiology: inflammation of the pes anserine bursa
Remember it is deep to the gracilis, sartorius, and semitendinosus tendons at the lower medial knee

Common symptoms/ complaints:
Localized pain medial knee just below joint line
Mild swelling occasionally
Commonly seen in runner (hills/stairs)

Question 22

Knee: Pes Anserine Bursitis

PE and tests

Answer 22

Physical Exam:
Medial knee pain just 2-3cm below the joint line

Tests: Clinical findings

Question 23

Knee: Pes Anserine Bursitis

Tx and pearls

Answer 23

Treatment:
Rest
Modify activity
NSAIDs
Steroid injection (typically does not swell enough for aspiration because of compression from the tendons)
Rarely needs surgery

Pearls:
Often can be confused with medial joint arthritis or medial meniscus tear since it is tender in a similar location

Question 24

Knee: Baker’s Cyst (popliteal)

etiology and common complaints

Answer 24

Etiology:
Cyst forms (like a ganglion cyst) on the back of the knee (either from the joint or from one of the posterior tendon sheaths)
Commonly associated with intraarticular knee disorders (OA, meniscal tears due to excessive fluid formation)

Common symptoms/ complaints:
Swelling
Trouble with flexion
Not really painful

Question 25

# Knee: Baker’s Cyst PE and Tests

Answer 25

Physical Exam: **No effusion of knee** Palpable “lump” due to localized swelling to posterior knee +/- swelling of lower leg **Reduced knee flexion** Tests: **MRI or ultrasound is absolutely needed to be sure it is not from a blood vessel (aneurysm)**

Question 26

# Knee: Baker’s Cyst Tx and pearls

Answer 26

Treatment: Rest & monitor Modify activity Aspiration and steroid injection Surgical excision if painful, compressive vascular structures or conservative approach fails Pearls: Like other cysts, it might return

Question 27

# Knee: ACL Tear Etiology and presentation

Answer 27

Etiology: Tear of ligament, usually because of twisting injury or direct blow to the knee Often because of sport injury – basketball. soccer Presentation: **Pain deep in knee (not always) Instability “Pop” in the knee Immediate swelling/effusion**

Question 28

# Knee: ACL Tear PE and tests

Answer 28

Physical Exam: Effusion Little to no TTP **+ Lachman + Anterior drawer** “Quadriceps avoidance” – do not want to extend the knee Tests: MRI Lachman + Anterior drawer test +

Question 29

Answer 29

Question 30

# Knee: ACL Tear Tx

Answer 30

Treatment: Almost always need surgical repair (unless older and inactive) - Femoral/tibial tunnel, graft fixation - Bone-Patella-Bone autograft*, quad tendon/ham autograft, allograft - Repair associated damaged structures (meniscus/MCL) ACL brace during recovery controversial Physical therapy after surgery Pearls: Often associated with MCL or medial meniscus injury (50%)

Question 31

# Knee: PCL Tear etiology and presentation

Answer 31

Etiology: Tear of the PCL related to **hyperextension or direct blow to flexed knee (dashboard or athletic injuries)** Presentation: Posterior knee pain, instability, swelling

Question 32

# Knee: PCL Tear PE and tests

Answer 32

Physical Exam: Pain w/effusion Feeling of instability with posterior movement +posterior drawer +sag sign Tests: MRI + posterior drawer test

Question 33

# Knee: PCL Tear Tx

Answer 33

Treatment: Usually does **not** require surgery (unlike ACL) unless the patient is an athlete Surgical intervention typically if multiple ligaments are compromised Can manage conservatively Rest, ice, bracing, PT – quad strengthening exercises 6-12 months for full recovery

Question 34

# Knee: MCL Tear Etiology and common complaint

Answer 34

Etiology: Forceful valgus stress to lateral aspect of the knee (direct lateral blow to knee) Most common ligamentous injury Common in athletes – skiing, rugby, soccer, football Common symptoms/ complaints: Pain at medial knee Instability Edema

Question 35

# Knee MCL tear PE and Tests

Answer 35

Physical Exam: Effusion Ecchymosis Medial joint line TTP Instability with valgus stress Tests: MRI +Valgus stress test

Question 36

# Knee: MCL Tear Tx and pearls Incomplete vs complete

Answer 36

Treatment: Incomplete tear: NSAIDs, rest, PT, bracing with immobilization or hinged brace Complete tears will sometimes need surgery, depends on if it is isolated or unstable with other structures are damaged Pearls: Typically, will have medial meniscus or ACL damage Often not an isolated injury

Question 37

# Knee: LCL Tear Etiology and presentation

Answer 37

Etiology: Varus stress to the medial knee tears the LCL **Traumatic blow to medial knee** Most often seen in **gymnasts and tennis** players Presentation: Pain/swelling along lateral knee Instability near full knee extension – difficulty using stairs & cutting/pivoting Swelling

Question 38

# Knee: LCL Tear PE and test

Answer 38

Physical Exam: Effusion TTP over lateral joint line of knee Effusion Ecchymosis Pain with varus stress Tests: **MRI** – most tears are the fibular insertion **+ Varus stress test**

Question 39

# Knee: LCL Tear Tx and Pearls

Answer 39

Treatment: **Incomplete tear**: NSAIDs, rest, PT, bracing with immobilization or hinged brace - Return to sports 6-8 weeks **Complete tears** will usually need surgery, depends on if it is isolated or other structures are damaged Pearls: Typically, will have other structures damaged Often not an isolated injury Failed PCL and ACL reconstructions will happen if there is an LCL injury that was missed and not repaired

Question 40

# Knee: Lateral or Medial Meniscus Tear etiology and presentation

Answer 40

Etiology: Tear of the cup-like structure as a result of twisting or deep squat Acute sports injuries in younger patient Degenerative condition in older population Medial more common (except in ACL tears) Presentation: Pain Clicking/locking/pop Knee “giving out” sensation Delayed/intermittent swelling

Question 41

# Knee: Lateral or Medial Meniscus Tear PE and tests

Answer 41

Physical Exam: Vague localized pain at joint line Delayed swelling +McMurray test Otherwise fairly normal Can occasionally get popping/locking reproducible when squatting Tests: MRI

Question 42

# Knee: Lateral or Medial Meniscus Tear Tx

Answer 42

Treatment: Conservative: Rest, NSAIDs, PT Operative: if symptoms do not resolve or tear is very large Arthroscopy can be therapeutic and diagnostic Repair for large tears in outer third; debridement for other tears

Question 43

# Knee: Chondromalacia Patella etiology and complaints

Answer 43

Etiology: Breakdown of the cartilage on the back of the patella and in the patellofemoral groove Limb malalignment, muscle weakness, patella maltracking Common symptoms/ complaints: Anterior knee pain with activity (especially squatting, prolonged sitting, and stairs)

Question 44

# Knee: Chondromalacia Patella PE and Tests

Answer 44

Physical Exam: Peripatellar pain with patellar compression Insidious (vague) onset Patellar maltracking with ROM Crepitus with flexion and extension Tests: Clinical exam, radiographic findings: sunrise to show abnormal tracking, MRI to assess articular cartilage