TOTAL HIP PROSTHESIS WITH FEMORAL OSTEOTOMY FOR MAJOR MISLIGNMENT: AN ORIGINAL TECHNIQUE AND PROSPECTIVE RESULTS IN 60 CONSECUTIVE HIPS

Abstract

Purpose of the study: Implantation of a total hip arthroplasty (THA) for major misalignment is a difficult procedure and few results have been published. In the 1950s to 1970s, supra-trochanteric osteotomy was proposed for sequelar osteoarthritis of congenital hip dislocation. Subsequent degradation 20 to 30 years later can lead to neo-osteoarthritis of the joint with an effect on hip alignment and overall balance between the knee and the spine. We present a prospective consecutive series of 60 THA performed from 1991 to 2003on hips with Milch and Schanz osteotomies.

Material and methods: The objective was to reconstruct an anatomic hip joint by femoral re-alignment de-osteotomy, inferior displacement of the hip joint to enable insertion of an implant with a correctly position center of rotation and normal muscle lever arms. The technique was novel because of the direct approach to the subtrochanteric angle. The step by step procedure enabled insertion of the prosthesis without trochanterotomy. Overall recovery was long, often 12 to 18 months. There were 47 patients 60 hips) with at least 18 months follow-up. None of the patients were lost to follow-up.

Results: Results were available for 54 hips (three deaths, six hips). Mean follow-up was eight years. Outcome was good (patient satisfaction, normal x-ray) for 77%. Twelve hips presented poor clinical and radiological results due to loosening and mobilization of the femoral implant with or without nonunion of the deosteotomy. Ten hips were revised at mean five years via a femoral access for insertion of a press-fit distally locked prosthesis with graft of the nonunion (with acetabular replacement in one hip). The outcome was good at last follow-up for nine of these hips. One repeated revision gave satisfactory results.

Discussion: The only factors of risk of failure were related to femoral re-alignment and absence of trochanterotomy. A lesser risk of nonunion was related to the technique used for osteotomy, osteosynthesis and grafting. The use of a non-cemented implant with a solid primary stability and in certain cases a custom-made implant can be discussed for selected patients.