A 30-year-old woman comes to the office for evaluation of left knee pain. She was participating in a recreational hockey tournament over the weekend when she collided with another player, and they both hit the wall. The patient was able to skate off the ice but noted some tightness in the left knee. She had partial pain relief with ice and elevation of the left leg but noticed that her knee was somewhat swollen the next morning. On examination, the patient has a small left knee effusion without erythema or palpable warmth. There is tenderness at the medial aspect of the knee at the joint line, but gait is normal. With the patient standing on the left leg and the knee bent slightly, internal rotation on the knee elicits a click and significant, sharp pain. X-ray of the knee joint reveals no abnormalities. Which of the following is the most likely diagnosis in this patient?

Question

A 30-year-old woman comes to the office for evaluation of left knee pain.  She was participating in a recreational hockey tournament over the weekend when she collided with another player, and they both hit the wall.  The patient was able to skate off the ice but noted some tightness in the left knee.  She had partial pain relief with ice and elevation of the left leg but noticed that her knee was somewhat swollen the next morning.  On examination, the patient has a small left knee effusion without erythema or palpable warmth.  There is tenderness at the medial aspect of the knee at the joint line, but gait is normal.  With the patient standing on the left leg and the knee bent slightly, internal rotation on the knee elicits a click and significant, sharp pain.  X-ray of the knee joint reveals no abnormalities.  Which of the following is the most likely diagnosis in this patient?

Quizplus · Accepted Answer

11ec25c8_d96a_e1ce_bc81_6b82f6075211_MD0003_00 Tears of the medial meniscus often result from twisting force with the foot in a fixed position. Patients generally report a popping sound followed by acute pain. Associated symptoms can include reduced extension, a sensation of instability, and knee effusion. Because the meniscus is not directly perfused, rapid-onset hemarthrosis does not occur and any effusion that develops is typically not immediately apparent. The medial meniscus is more commonly injured than the lateral. Examination reveals tenderness at the joint line on the affected side. Patients may also have palpable locking or catching when the joint is rotated or extended while under load; characteristic maneuvers include the Thessaly (as in this patient) and McMurray tests. X-ray may reveal osteoarthritis in older patients with tears caused by chronic degeneration of the cartilage, but plain films are usually normal in young patients with traumatic tears. Diagnosis is confirmed with MRI or arthroscopy. Thessaly McMurray (Choices A and C) Pes anserinus syndrome (anserine bursitis) is characterized by pain and tenderness at the anterior medial knee distal to the joint line. Iliotibial band syndrome causes lateral pain with tenderness at the lateral femoral condyle. These chronic overuse injuries do not cause effusions or locking of the knee. (Choice B) Anterior cruciate ligament tears are caused by forceful hyperextension of the knee or torsional injury during deceleration. Rapid-onset hemarthrosis is typical, and patients have anterior laxity of the tibia relative to the femur (eg, Lachman test, anterior drawer sign). (Choice D) Medial collateral ligament injury can occur by a blow to the lateral knee or forceful leg abduction. It would cause medial knee tenderness but would not be associated with catching during extension or rotation. (Choices F and G) Patellar dislocation occurs after quick lateral movements around a flexed knee. Examination reveals a flexed knee with the patella displaced laterally. The patellar tendon is rarely ruptured, although tears can occur with extreme loading in knee flexion. Rupture of the patellar tendon causes impaired knee extension. (Choice H) Patellofemoral pain syndrome causes chronic anterior knee pain. Patients experience pain worsened by activity or prolonged sitting (due to sustained flexion) and may also have crepitus with motion of the patella. Educational objective: Tears of the medial meniscus often result from twisting injuries with the foot in a fixed position. Associated symptoms can include reduced extension, a sensation of instability, and a knee effusion. Examination reveals palpable locking or catching when the joint is rotated or extended while under load. Diagnosis is confirmed with MRI or arthroscopy.

A 30-Year-Old Woman Comes to the Office for Evaluation of Left