Greater trochanteric overgrowth: development and surgical correction.

Greater trochanteric advancement (GTA) is an orthopedic procedure designed to correct the biomechanical consequences of overgrowth of the greater trochanter by moving the greater trochanter and its attached muscles laterally and distally. Thirty-one children with trochanteric overgrowth who had secondary pelvic instability (Trendelenburg sign) were studied and underwent a total of 33 GTA procedures. The clinical and radiologic prerequisites for successful surgery are presented. In addition, the radiographic methods of measuring the lateral position of the trochanter, the articulotrochanteric distance, and the amount of trochanteric overgrowth are discussed. Measurements made on preoperative and postoperative radiographs revealed that surgery achieved a mean displacement laterally of 12.1 mm and distally 21 mm. Clinically, there were few complications (two children with mild myositis, one with broken hardware, one with delayed union of trochanter). Pelvic instability had disappeared in the 25 of the 30 patients who could be evaluated.