Prosthetic Hip Failure: Preliminary Findings of Retrospective Radiograph Image Analysis

Abstract

We present the results of a retrospective study based on radiographs of 75 successful total hip replacements, and 103 which involved failure of the femoral component of the prosthesis. The failures were selected to exclude cases in which infection was implicated. Success was defined as absence of adverse clinical or radiological symptoms for at least 12 years after surgery. A failure was either obvious, for example, stem fracture, or defined as one which showed progressive radiological and clinical degeneration resulting in the need for revision surgery. Measurements were made on radiographs which had been obtained immediately post-operatively, so that the features measured would depend on surgical procedure rather than on any subsequent biological response. Computer image analysis has been used to make precisely defined, reproducible measurements of 58 parameters characterising the insertion of the femoral component of a standard Charnley prosthesis. These parameters include geometry of insertion, distribution of cement, surrounding bone thickness, and so on. Clinical findings, including patient weight, were also recorded with the measurements on computer disc. Preliminary statistical comparisons indicate that several of the measured parameters are of predictive value for determining the long-term success or failure of total hip replacements.