ASR revision surgery – patient reported outcomes

Abstract

Introduction The articular surface replacement (ASR) metal on metal (MoM) hip prostheses have a reported failure rate, in both its resurfacing and ASR XL Acetabular system form, of up to 12–13% of cases at 5 years. Such unacceptable outcomes led to the recall of the ASR hip system in Ireland in 2010. The numbers of ASR revision procedures performed began to rise after the recall date. The Western Ontario and McMaster Universities Arthritis Index (WOMAC score) has been shown to be a useful predictive index regarding the need for revision in this cohort. Materiel et methodes A retrospective cohort study was performed. All ASR surgeries performed by one surgeon between 2004 and 2010 were identified and the subsequent revision rate was calculated. Each patient who had undergone revision surgery was contacted and asked to provide an up-to-date WOMAC score and Modified Harris Hip Score (mHHS). Patient demographics, intraoperative histology and the effect of revision on chromium and cobalt ion levels were also analysed. Resultats There was a total of 274 ASR procedures performed, with a cumulative revision rate of 13.8% (38 subsequent revisions, in 37 patients). Thirty-six of the 38 revisions (94.7%) were performed following the ASR recall in 2010. The mean WOMAC score deteriorated post revision. The mean mHHS was reported to be within the “failure” category. Discussion This study reports an ASR rate similar to that quoted in the literature. Selection criteria for revision surgery were likely influenced by the recall in 2010 given that the majority of cases were performed thereafter. Patients who have undergone revision surgery report unsatisfactory outcomes. Conclusion A reliable marker to predict postoperative pain and function postrevision ASR surgery is required in order to improve patient selection and ensure satisfactory outcomes.