Osteochondritis dissecans

1. What is osteochondritis dissecans?
2. How does OD present?
3. How is it diagnosed?
4. What is the treatment?

Answers:
1. Localized area of avascular necrosis of end of long bone with degeneration of overlying cartilage, which may detach and enter joint space. Medial femoral condyle is most often affected.
2. Primarily seen in adolescents. Joint pain and irritation, synovial effusion, buckling, locking.
3. Radiographs, CT.
4. Rest, NWB on knee. If no healing or if fragment detaches, surgical excision may be required.

Jumper's knee

1. What is jumper's knee?
2. How does jumper's knee present?
3. How is jumper's knee treated?

Answers:
1. Patellar tendinitis associated with micro-tears of the tendon, associated with jumping, squatting and kneeling.
2. Pain on activity, worse after activity. Tenderness at inferior or superior pole of patella.
3. Same treatment of patellofemoral syndrome.

Plica

1. What is plica of the knee?
2. What is the presentation of plica?
3. How is plica diagnosed?
4. What is the treatment of plica?

Answers:
1. Plica is a redundant fold in the synovial lining of the knee, which is susceptible to tearing.
2. Insidious onset of anterior knee pain, especially with prolonged knee flexion or sitting. The plica can also become inflamed after knee trauma.
3. MRI, arthrogram, and arthroscopy.
4. Treatment same as for patellofemoral syndrome. Consider surgery if conservative measures fail.

Patellar chondromalacia

1. What is chondromalacia of the patella?
2. What predisposes to patellar chondromalacia?
3. What imaging should be ordered?
4. What is the treatment?

Answers:
1. Softening of the patellar articular cartilage, which is the culmination of cartilage degeneration.
2. Chronic patellofemoral overload and tracking dysfunction, infection, trauma, autoimmune processes.
3. CT or MRI may detect defects in articular cartilage of patella.
4. Correct abnormal patellar mechanics.

Patellofemoral pain

1. What is patellofemoral pain?
2. What is the presentation of patellofemoral syndrome?
3. What conditions predispose to PF syndrome?
4. What imaging is required for PF syndrome?
5. What is the nonsurgical treatment of PF syndrome?
6. What are surgical options for PF syndrome?

Answers:
1. Overuse injury caused by repeated microtrauma leading to peripatellar synovitis.
2. Presentation is as anterior knee pain w/wo effusion or crepitus, worse with stairs.
3. High riding, laterally shifted patella, which may be due to VL tightness and relative medial weakness, tight lateral retinaculum, rotation of patella, tight hip flexors or abductors or hamstrings, increased Q angle.
4. X-ray to assess patella position. MRI not useful, CT used if growth plate involvement or tumor is suspect.
5. Use ice and NSAIDs in acute phase, patellar taping and bracing, therapy including strengthening of VMO, stretching of hamstrings, IT band, adductors, and VL, proprioceptive exercises.
6. Surgical options are lateral release of retinaculum, patellar realignment, patellar tendon transfer, patellectomy. Consider surgery if no improvement after 4-6 mo.
7.

Recurrent patellar subluxation

1. What are factors that may predispose to patellar subluxation?
2. What are the signs and symptoms of patellar subluxation?
3. What imaging should be done to assess for subluxation?

Answers:
1. Less prominent lateral lip or more prominent medial lip, increased genu valgum/varus, excessive genu recurvatum, vastus medialis weakness, tibial external torsion, shallow lateral femoral condyle, laterally attached infrapatellar tendon.
2. Knee buckling, pain and tenderness in the peripatellar region, effusion, wasting of vastus medialis, impaired extension.
3. Lateral view in 45 degrees knee flexion and in full extension, sunrise view.

Iliotibial band syndrome

1. Where does the ITB insert?
2. What is the presentation of ITB syndrome?
3. What is the treatment of ITB syndrome?

Answers:
1. On Gerdy's tubercle on the lateral tibia.
2. Pain over lateral femoral condyle, worse with running and walking.
3. Stretching of ITB, hip flexors, gluteus maximus, strengthening of hip abductors, gluetus maximus, and TFL. Injection for resistant cases.

MCL/LCL injuries

1. What is a common cause of MCL injury?
2. What are the exam findings of MCL injury?
3. What imaging is indicated for MCL injury?
4. What is the treatment of MCL injury?
5. How do LCL tears usually occur? How are they evaluated?

Answers:
1. MCL tears occur in football and skiing and are from force to the lateral knee.
2. Exam shows medial swelling and tenderness, minimal effusion, and medial instability.
3. Radiographs may show epiphyseal fracture. MRI delineates the MCL tear and evaluates the ACL and medial meniscus (O'Donaghue's triad).
4. Treat conservatively with knee bracing and strengthening.
5. LCL tears usually occur with knee dislocation. Patient with LCL tear should also be evaluated for associated vascular injury and cruciate and peroneal nerve injuries.

PCL injuries

1. How do PCL injuries often occur?
2. What is the history and physical exam findings for PCL injury?
3. What imaging is used to diagnose PCL injury?
4. What is the treatment of PCL tear?

Answers:
1. Most frequent cause is hitting the front of the tibia with the knee flexed (dashboard injury) or hyperflexion in athletes. Less common than ACL.
2. May be a pop, minimal swelling that increases over 24 hours. Exam shows popliteal tenderness, an effusion, positive posterior drawer and sag tests.
3. MRI less accurate than for ACL, arthroscopy more accurate than MRI.
4. Surgical repair if ligament is avulsed, quadriceps strengthening.

ACL injuries

1. What is the typical mechanism of ACL injury?
2. What is O'Donoghue's triad?
3. What are the symptoms of ACL injury? What are the physical exam findings?
4. What imaging is done for ACL injury?
5. What is the treatment of ACL injury?


Answers:
1. Cutting, deceleration, and hyperextension of the knee, often noncontact injury (football, soccer, downhill skiing). 50% occur with meniscal tears.
2. ACL injury, MCL injury, and medial meniscus injury (since MCL is attached to medial meniscus).
3. Sudden pop with anterior knee pain and posterolateral joint line pain, instability, early swelling. PE shows effusion, tenderness, anterior drawer and Lachman's may be positive.
4. MRI or arthroscopy.
5. If reconstruction is done, partially WB with ROM over first two weeks, then progress to closed chain kinetics. Sports-specific exercises in 6-12 wks.

Meniscal injuries to the knee

1. How do medial and lateral meniscus injuries usually occur?
2. What are the symptoms of acute and degenerative meniscus injury?
3. What is seen on physical exam?
4. What is the imaging gold standard for meniscus injury diagnosis?
5. What is the treatment?

Answers:
1. Medial meniscus: injured with tibial rotation while knee partially flexed (football, soccer). Lateral meniscus: injured during squatting in full flexion with rotation (wrestling).
2. An acute tear is associated with a pop with true locking, effusion, and knee stiffness. Degenerative tears involve minimal trauma in >40 yrs.
3. Decreased ROM, flexion limited by effusion, tenderness at jt line, positive Apley and McMurray tests.
4. MRI.
5. Injury to inner 2/3 of meniscus needs surgery due to poor vascularization. NWB for 4-6 wks after surgery if meniscus repaired, WBAT in 1-2 days if meniscus is removed.

Test of the knee ligaments

1. What may cause an anterior drawer test to be falsely negative?
2. What is the sag test?
3. How does Lachman's test compare to anterior drawer in sensitivity?

Answers:
1. Hemarthrosis, hamstring spasm, meniscal tear, and other structures (posterior capsule) can limit forward movement of tibia.
2. Test for PCL patency. Place patient supine with knee flexed 90 degrees, test is positive if tibia is displaced posteriorly.
3. Lachman's test, in which knee is flexed 15-30 degrees and anterior force is applied to tibia, is more sensitive than anterior drawer.

Physical exam of the knee

1. What is the McMurray test best used for?
2. What is Apley's Grind Test?
3. What is Apley's Distraction Test?
4. What is the Patella Femoral Grind Test?

Answers:
1. Diagnosis of posterior meniscal tears.
2. Test for diagnosis of torn meniscus. Patient lies prone with knee flexed 90 deg while examiner places downward force on heel while rotating tibia. A positive test elicits pain.
3. Test for ligamentous damage. Same as Grind Test, but a traction is applied rather than a downward force, reducing stress on meniscus. Positive test elicits pain.
4. Test to evaluate quality of patella articulating surfaces. Patient is supine with legs in neutral, while examiner pushes on patella distally while patient contracts quads. Patella should glide smoothly up. Positive test is pain and crepitation.

Bursae of the knee

1. What are the anterior bursa of the knee?
2. How is the prepatellar bursa inflamed?
3. How is the superficial infrapatellar bursa inflamed?
4. How many lateral bursae are there?
5. Where is the pes anserinus bursa located?
6. What is a Baker's cyst?

Answers:
1. Prepatellar bursa, suprapatellar bursa, deep infrapatellar bursa, and superficial infrapatellar bursa.
2. The prepatellar bursa is the most commonly damaged, caused by prolonged kneeling: housemaid's knee.
3. Associated with kneeling in an upright position: vicar's knee.
4. Three.
5. Located between the pes anserinus tendons and the MCL.
6. Distension of the bursa between the medial head of the gastrocnemius and the capsule, which is an outpocketing of the synovial membrane.

Other ligaments of the knee

1. Where does the medial collateral ligament attach?
2. Where does the lateral collateral ligament attach?
3. What are the capsular ligaments? What is the function of the capsular ligaments?
4. What is the function of the oblique popliteal ligament? Where does it attach?
5. What is the function and attachment of the arcuate popliteal ligament complex?
6. What can the APLC be mistaken for on MRI?

Answers:
1. The MCL attaches to the medial femoral condyle, to the medial upper end of the tibia, and it has an attachment to the medial meniscus.
2. The LCL attaches to the lateral femoral condyle, to the upper end of the lateral fibula.
3. Tibial collateral ligament, oblique popliteal ligament, arcuate ligament, and fibular collateral ligament.
4. The OPL, which resists knee extension, arises from the semimembranosus tendon and is attached to the posterior capsule and lateral meniscus.
5. The APLC provides attachment for the posterior horn of the lateral meniscus. Its function is to reinforce the lateral knee and prevent posterior tibial subluxation.
6. A tear of the posterior horn of the lateral meniscus.

Ligaments of the knee: ACL and PCL

1. Where does the ACL attach?
2. What is the function of the ACL?
3. If the ACL is deficient, where is extra pressure placed?
4. Where does the PCL attach?
5. What is the function of the PCL?
6. If the PCL is deficient, where is extra pressure placed?

Answers:
1. The ACL attaches to the lateral intercondylar notch (of the femur) and to a point lateral to the medial tibial eminence.
2. Prevents anterior tibial subluxation, prevents backward sliding of femur and hyperextension of knee. In flexion, it draws the femoral condyles anteriorly.
3. Posterior menisci.
4. The PCL attaches to the medial intercondylar notch and to a point lateral to the posterior tibial plateau.
5. Restrain posterior tibial subluxation.
6. Patellofemoral joint.

Menisci of the knee

1. What is the function of the menisci of the knee?
2. What is the vascular supply of the menisci?
3. What are the shapes of the two menisci?

Answers:
1. The menisci are fibrocartilage of crescent shape, which deepen the articular surface of the tibia for stability.
2. The peripheral 1/3 of the menisci are well vascularized and the inner 2/3 of the menisci are not well vascularized and can't usually be surgically repaired.
3. The medial meniscus is C-shaped and adheres to the MCL. The lateral meniscus is circular.

Knee functional anatomy

1. What are the knee extensors?
2. What are the knee flexors?
3. What are the knee medial rotators?
4. What are the knee lateral rotators?
5. What is the function and innervation of the popliteus?

Answers:
1. Quadriceps.
2. Lateral and medial hamstrings, sartorius, gracilis, gastrocnemius.
3. Medial hamstrings, sartorius, gracilis.
4. Biceps femoris.
5. The popliteus locks and unlocks the knee. It is innervated by the tibial nerve (L4, L5, S1).