What is a good patient reported outcome after total hip replacement?

OBJECTIVES: There is an increasing movement to collect and report patient reported outcome measures (PROM's) following total hip replacement (THR). In the UK, the procedure specific PROM of choice is the Oxford Hip Score (OHS). It is currently unclear how to use this information to determine outcome following surgery. The aim of this study was to define a threshold for the OHS that is correlated with patient satisfaction.
DESIGN: Prospective cohort study.
SETTING: A district general hospital (St. Helier Hospital, Carshalton, UK). PARTICIPANTS: 799 patients receiving THR from 1995 to 2004. MAIN OUTCOME MEASURES: At 12 and 24 months after surgery patients were asked if they were satisfied with surgery and completed the OHS. Receiver operating characteristic (ROC) analyses were used to identify thresholds of follow-up OHS, which best discriminated patient satisfaction. Analyses were stratified by age, sex, body mass index (BMI), baseline OHS and patient expectations.
RESULTS: 91.9% of patients were satisfied with THR at 12 months (92.8% at 24 months). Using the ROC technique, the OHS at 12 months associated with patient satisfaction was 38 and at 24 months 33. The OHS at 24 months associated with satisfaction was higher in those with highest tertile of baseline OHS (30, 33, 43 respectively), and lowest tertile of BMI.
CONCLUSIONS: We have identified a value of the OHS that predicts patient satisfaction 12-24 months following THR within a standard clinical setting. However, this threshold is markedly influenced by pre-operative OHS and should be stratified accordingly.