Transchondral drilling for osteochondritis dissecans of the medial condyle of the knee.

Osteochondritis dissecans is a rare condition which occurs most frequently in the medial condyle of the knee. Its prognosis remains controversial. We report our experience with transchondral drilling (TCD) for osteochondritis dissecans. The rationale for this low-morbidity procedure is to enhance the healing potential of a lesion which failed to heal after conservative treatment. This multicenter retrospective study examined 24 patients (25 medial condyles), including cases both before (juvenile osteochondritis dissecans, JOCD; n=17) and after closure of the physis (adult osteochondritis dissecans, AOCD; n=8). All patients initially underwent a prolonged conservative treatment. The mean duration of symptoms prior to surgery was 22 months in JOCD and 55 months in AOCD patients. TCD was proposed in cases of intact or almost intact articular cartilage and was initially conducted under arthrotomy and later by arthroscopy. Mean follow-up time was 11.8 years in JOCD and 6 years in AOCD, and evaluation was based on clinical examination and radiography. Excellent clinical results were only observed in the JOCD group (12/17). In the AOCD group 4 patients had a good result and the other 4 a poor result. Radiological findings matched with clinical results. Except for age, factors of poor prognosis were: fissure of the articular cartilage and anterior extension of the lesion. We do not recommend TCD for AOCD. In JOCD, failure after 12 months of conservative treatment should indicate TCD in the cases where the cartilage remains continuous. At this stage there is no indication for more aggressive procedures.