Distal greater trochanteric transfer in the treatment of deformity of the proximal femur caused by avascular necrosis.

Background. Distal greater trochanteric transfer is one of the surgical methods used to correct proximal femoral deformity arising in the course of treatment for developmental dysplasia of the hip. Material and methods. We reviewed a series of 49 patients (55 hips) who had undergone distal greater trochanteric transfer at the mean age of 13.9 years due to deformity of the proximal femur after treatment for developmental dysplasia of the hip, in order to verify the value of the procedure. The mean follow-up was 15 years. Clinical and radiological assessment was supplemented with strain-gauging evaluation of the muscles involved. Results. Good results were achieved in those patients who had good range of movement or isolated restriction of abduction before the operation. After surgery, a 22% increase of abductor torque was found, the Trendelenburg sign disappeared in 30 individuals, and 15 patients regained normal gait. Conclusions. Distal greater trochanteric transfer improved hip joint biomechanics. Good abduction/adduction range of hip movement was essential for clinical improvement and increased muscle strength after surgery. Arthritic changes occurred primarily in those hip joints without clinical improvement. Distal transfer of the greater trochanter delayed osteoarthritis of the hip.