The long-stem Exeter femoral component is commonly used in revision hip surgery. Subsidence of the femoral stem in primary hip arthroplasty has been studied extensively, but much less is known about its significance in revision surgery. This prospective study examined the relationship between radiological subsidence, Western Ontario and McMaster (WOMAC) osteoarthritis index pain score, patient satisfaction and complication rates for the long-stem Exeter hip prosthesis.
Data was prospectively collected for a single-surgeon series of 96 patients undergoing revision surgery with a mean follow-up period of 36 months. Pre- and post-operative clinical evaluation was carried out using the validated WOMAC osteoarthritis index. Radiographic evaluation was carried out on magnification-adjusted digital radiographic images.
Data from 57 patients were analysed. The mean rate of subsidence recorded was 0.43 mm/year, with a mean total subsidence of 0.79 mm [95% confidence interval (CI) 0.57-1.01] at 36.3 months. There was no correlation between subsidence and post-operative WOMAC score, complication rate or patient satisfaction. There was a statistically significant reduction between pre-operative and post-operative WOMAC scores, with means of 33.5 and 10.7, respectively (P < 0.001), and high patient satisfaction.
Our subsidence rates for long-stem revision femoral components are lower than the published data but demonstrate the same plateau. Radiographic subsidence does not appear to relate to functional outcome or complication rates in our data.