Preoperative Gait Speed as a Predictor of Patient-Reported Outcomes After Total Hip Arthroplasty

Background: Total hip arthroplasty (THA) is a well-established procedure for hip osteoarthritis (OA); however, its clinical outcomes are variable, and the optimal timing for surgery remains unclear. Identifying the preoperative predictors that influence midterm patient-reported outcome measures (PROMs) could improve patient outcomes. Methods: This retrospective cohort study included 274 Asian patients who underwent primary THA for OA between 2012 and 2018, who completed preoperative physical assessments, and who responded to a postoperative mail survey. Preoperative variables included symptom duration, pain intensity, hip range of motion, lower-limb muscle strength, and 10-m free gait speed. PROMs were assessed using the Oxford Hip Score (OHS) and the Forgotten Joint Score-12 (FJS-12). Clinically meaningful outcomes were assessed using the Patient Acceptable Symptom State (PASS), defined as a score of ≥42 for the OHS and a score of ≥50 for the FJS-12. Additionally, K-means clustering was applied to categorize patients into an excellent outcome group and a control group on the basis of their PROMs. Results: Multivariable regression analysis revealed that preoperative gait speed significantly predicted both the OHS and FJS-12 outcomes (p < 0.01). Furthermore, hip flexion range of motion and hip flexion strength were significantly associated with preoperative gait speed (p < 0.01). A receiver operating characteristic (ROC) curve analysis identified a gait speed cutoff value of 0.7 m/s for achieving the PASS for the OHS (area under the curve [AUC]: 0.69; p < 0.01) and a cutoff value of 1.0 m/s for achieving the PASS for the FJS-12 (AUC: 0.60; p = 0.01). K-means clustering identified preoperative gait speed as the sole significant predictor of classification into the excellent outcome group (odds ratio, 5.85; p < 0.01). The ROC curve analysis revealed a gait speed cutoff value of 1.0 m/s for classification into the excellent group (AUC: 0.64; p < 0.01). Conclusions: Preoperative gait speed, which reflects decreased mobility due to hip joint dysfunction, was a significant predictor of midterm PROMs after THA. Maintaining a preoperative gait speed of 1.0 m/s could serve as a critical threshold for achieving favorable postoperative outcomes, regardless of patient age. Level of Evidence: Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.