Figure. Anteroposterior radiograph of the left knee.
A 14-year-old boy presents to the office with pain in his left knee after playing basketball 2 days earlier. Examination of the knee reveals a grade I medial collateral ligament (MCL) sprain, and a large 1.6-cm osteochondral lesion on the medial femoral condyle is incidentally noted on radiographic examination (Figure). Magnetic resonance imaging (MRI) of the knee shows intact articular cartilage with no reactive edema around the osteochondral lesion.
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The patient has a large asymptomatic osteochondral lesion of the medial femoral condyle. MRI shows intact articular cartilage over the osteochondral lesion and no increased signal intensity in the surrounding bone, representing a stable lesion. This lesion was found incidentally on radiography and is not the cause of the patient’s symptoms. Sprain of the MCL in skeletally immature patients with an open physis and a stable lesion will usually heal with nonoperative treatment. Stable osteochondral lesions often become asymptomatic long before imaging demonstrates signs of healing and resolution of bone marrow edema. For that reason, serial radiographs or additional MRI imaging is usually not necessary for asymptomatic patients with stable lesions. Skeletally immature patients who are symptomatic and have unstable lesions are unlikely to heal with conservative treatment and usually require surgery to prevent early-onset arthritis. Osteochondral lesions in adults usually require operative treatment to prevent detachment of the osteochondral lesion and early-onset arthritis. Restricting activities such as running and jumping in pediatric patients with asymptomatic lesions has not been shown to improve outcomes.1,2
Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor-in-chief of the Journal of Orthopedics for Physician Assistants.
1. Wall EJ, Vourazeris J, Myer GD, et al. The healing potential of stable juvenile osteochondritis dissecans knee lesions. J Bone Joint Surg Am. 2008;90(12):2655-2664.
2. Karadsheh M. Osteochondritis dissecans. https://www.orthobullets.com/knee-and-sports/3028/osteochondritis-dissecans. Updated March 19, 2018. Accessed December 27, 2019.