Effect of the position of the greater trochanter on the rate of union after trochanteric osteotomy for total hip arthroplasty.

The correlation between the position of the greater trochanter and the rate of union of the trochanteric osteotomy was assessed in 85 patients who had unilateral total hip arthroplasty using U-bolt fixation of the trochanter. The position of the trochanter was assessed radiologically immediately after operation and at 3-month intervals for 1 year to ascertain the rate of union of the trochanteric osteotomy. The initial postoperative position of the trochanter was classified as either: group 1, trochanter anatomically reduced; group 2, trochanter reattached with some distal displacement; group 3, superomedial tilt of the trochanter (ie, loss of contact with the femoral shaft distally); or group 4, combination of distal displacement and superomedial tilt of the trochanter. The original reduction of the greater trochanter appears to influence its rate of union to the femoral shaft directly. Anatomic reduction or slight distal overlap of the trochanter resulted in union of the osteotomy within 6 months. Fixation of the trochanter in a tilted position invariably led to a delay in union and in nine cases (10.6%) led to a nonunion.