Operative treatment of osteochondritis dissecans in situ by retrograde drilling and cancellous bone graft: a preliminary report.

Four cases of osteochondritis dissecans, three of the knee and one of the talus in situ (prior to loosening of the fragment from its host bone) were successfully treated with modified drilling and bone grafting procedure. The procedure consists of retrograde insertion of a small guide pin through the radiolucent zone and osteochondral fragment to the subchondral bone, retrograde reaming of bone across the radiolucent zone into the osteochondral fragment with a bone biopsy needle, and cancellous bone grafting between the osteochondral fragment and the host bone. All lesions were found to be healed after more than six months' follow-up. Three patients had complete relief and the fourth had significant improvement of symptoms.