The long modified extended sliding trochanteric osteotomy.

The modified extended trochanteric osteotomy (ETO) preserves the posterior capsule and short external rotators through a lateral approach to the hip. The purpose of this study was to assess the performance of long ETOs, measuring 18 cm and above. Fifty three long ETOs were reviewed. The mean length of the osteotomy was 20.0 cm (range, 18-26). Mean scratch-fit length was 6.5 cm. Average follow-up was 57 months (range, 14-114 months). The Harris hip score improved from 37 preoperatively to 73 at last follow-up. Subsidence occurred in 12 (22.6%) cases. Eleven stems stabilised over the first year. One stem (1.9%) was revised for subsidence and loosening, one for a periprosthetic fracture and one for a fractured stem. Two (3.8%) cups had postoperative dislocations. Fifty two (98.1%) osteotomies united well. This series shows a low failure rate, with revision and union rates comparable to those reported for shorter ETOs. Performing the osteotomy through a lateral approach to the hip will enhance posterior stability.