A 22-year-old woman complains of several days of progressive knee pain after sustaining a twisting injury. Her knee is stable to valgus and varus stress and you find no laxity and no soft end point on anterior drawer testing. There is, however, an effusion and tenderness of the medial joint line and anterior joint space. She probably has:
An anterior cruciate ligament tear.
A posterior cruciate ligament tear.
A medial meniscal tear.
Valgus stress tests the medial collateral ligament, while the anterior drawer test is for assessing integrity of the anterior cruciate ligament. Meniscal injuries are typically caused by twisting injuries, and sometimes cause effusions. Chondromalacia patella is an overuse syndrome of the articular cartilage of the patella. Osteochondritis dessicans is a rare condition of unknown etiology commonly found in adolescents where the articular cartilage and subchondral bone become separated from the underlying bone.