Total hip replacement: modes of failure

Abstract

♦ Total hip replacements (THRs) may fail in various ways. They may become infected, they may be subject to aseptic loosening, they may dislocate, or a periprosthetic fracture may occur. The patient with a failed THR must be thoroughly assessed before treatment is contemplated♦ Infection may be acute or chronic. Assessment involves clinical assessment, plain radiographs, blood tests (C-reactive protein and erythrocyte sedimentation rate), hip aspiration, and, sometimes, nuclear medicine. The acutely infected hip may be treated with one-stage revision. This involves thorough lavage, debridement, and exchange of all modular components as well as long-term antibiotic therapy. The gold standard of treatment for a chronically infected THR is a two-stage revision. Success rates of 80–90% can be expected♦ Aseptic loosening typically occurs at the cement bone interface in hips where a metal-on-polyethylene bearing couple has been used. Bone resorption takes place as a result of an inflammatory response to small wear particles. After infection has been excluded the treatment of choice is a single-stage revision♦ Dislocation may be the result of patient factors, implant factors, or poor surgical technique. It is imperative for the clinician to minimize the risk by selecting patients carefully, using the correct combination of implants and performing surgery accurately♦ The management of periprosthetic fractures depends on how well the implants are fixed and quality of bone stock. Treatment ranges from simple fixation of the fracture through to revision augmented with strut allograft.