Osteochondritis dissecans of the medial femoral condyle associated with malformation of the menisci.

Osteochondritis dissecans is a form of osteochondrosis limited to the articular epiphysis and the relationship of osteochondritis dissecans and discoid lateral meniscus has been clearly identified. This article presents a 10-year-old boy with osteochondritis dissecans of the medial femoral condyle associated with hypoplastic medial and partial deficient lateral menisci. The patient presented with activity-related pain and intermittent swellings of his left knee for 2 months without any evidence of significant knee trauma. Magnetic resonance imaging revealed anomalous medial meniscus mimicking displaced bucket-handle tear and partially deficient lateral meniscus with osteochondritis dissecans at the lateral aspect of medial femoral condyle without any significant bone loss with a non-dislocated fragment. Arthroscopy of the knee revealed an incomplete separated osteochondral flap with partial discontinuity that was unstable on probing on the lateral aspect of the medial femoral condyle. The medial meniscus was hypoplastic without a body and only the meniscal rim could be seen. The lateral meniscus had an anomalous vertical insertion of the posterior horn, normal body, but an absent anterior horn. The anterior cruciate ligament was intact, but looked like a peacock's tail. Arthroscopic fixation of the chondral lesion was performed. At 30-months follow-up, the boy had no limitation in his daily and sports activity. The present case is the first description of congenital anomaly of the both menisci and osteochondritis dissecans together. Meniscal or ligamentous anomalies of the knee may be associated with osteochondritis dissecans.