Oxford Hip Scores, Floor-Sitting Score Trajectories, and Postoperative Satisfaction Rates at 10 Years After Primary Total Hip Arthroplasty

Background: Available evidence on outcomes at 5 years and beyond for total hip arthroplasty (THA) is mainly limited to patient-reported outcome measures (PROMs). This study documented the trajectory of functional measurement using the Oxford hip score (OHS) and floor-sitting posture in Japan for up to 10 years post-THA and investigated predictors of dissatisfaction at 10 years with THA. Methods: Patients scheduled for primary THA at a university hospital in Japan between 2003 and 2006 were enrolled in this prospective study. Overall, 826 preoperative participants were eligible for follow-up, with response rates ranging from 93.6% to 69.4% at each postoperative survey point. The OHS and floor-sitting scores were calculated using a self-administered questionnaire 6 times up to 10 years postoperatively. Patient satisfaction, including general surgery, walking ability, and activities of daily living (ADL), was assessed in the 10-year survey. Results: The linear mixed-effects model demonstrated a postoperative improvement, peaking at 7 years for OHS and 5 years earlier for the floor-sitting score. The postoperative overall surgical dissatisfaction at 10 years with THA was very low (3.2%). No predictors of surgical dissatisfaction were identified in the logistic regression analyses. Predictors of walking ability dissatisfaction were older age, men, and worse OHS at 1 year postoperatively. Predictors of ADL dissatisfaction were poorer preoperative and 1-year postoperative floor-sitting scores and 1-year postoperative OHS. Conclusion: The floor-sitting score is a simple PROM suitable for the Japanese population; other populations would require a scale suitable for their lifestyles.