Preservation of the femoral neck in hip arthroplasty: results of a 13- to 17-year follow-up

Abstract

In prosthetic surgery of the hip, it is important to remove only the pathological tissues, preserving as much as possible the osteo-articular architecture, in particular the femoral neck and the subchondral cencellous acetabulum. This allows the bone to easily adapt to the new biomechanical situation created by the prosthesis. Our long-term study of patients who underwent total hip replacement has confirmed such presuppositions. For this study, we used a biodynamic prosthesis, composed of a Lord hemispheric screwed cup with a biequatorial liner and an anatomical stem in Cr-Co-Md with a completely madreporic surface. This prosthesis is ideally configured to preserve the femoral neck. We followed 44 prostheses for 13–17 years. The clinical results were excellent or good in 82% of cases. Thigh pain, reported in only 14% of cases, spontaneously resolved. The mobility of the prosthetic hip and the consequent functional recovery were excellent, since conserving the neck re-stabilized the natural off-set, providing good equilibrium of the hip and the periarticular muscles. Radiographic analysis revealed survival of the femoral neck in approximately 80% of cases. The madreporic surface, when associated with correct positioning of an undersized stem, allowed for osteointegration with significant bone remodeling in the long term. Distal cortical hypertropy, found in 48% of cases, made it necessary to limit the madreporic surface finish to the stem's proximal two-thirds, leaving the distal one-third smooth.