"Trapdoor" procedure for osteonecrosis with segmental collapse of the femoral head in teenagers.

Osteonecrosis of the femoral head in adolescents often leads to serious destructive changes in the hip with resulting significant disability. Between March 1981 and June 1990 we treated 13 teenagers (14 hips) using the "trapdoor" bone grafting procedure for severe femoral head osteonecrosis with articular surface collapse. Nine cases (10 hips) had the trapdoor procedure combined with containment osteotomy of the femur and acetabulum. Thirteen of the 14 hips had adequate follow-up to be included in this report. The main focus of this report is the 10 hips treated with a trapdoor bone grafting plus containment procedure (femoral osteotomy, acetabular osteotomy, or both). At an average follow-up of 4 years 5 months, clinically seven cases (eight hips) had a good result and two had a fair result. Radiographic evaluation showed six hips with a good result, three hips with a fair result, and one with a poor result. None of these 10 hips has yet required hip fusion or replacement arthroplasty, suggesting that trapdoor bone grafting plus containment can serve as a procedure to delay the need for hip fusion in femoral head avascular necrosis in teenagers.