Stepping Toward Objective Outcomes: A Prospective Analysis of Step Count After Total Joint Arthroplasty

Background: Functional recovery monitoring after total hip arthroplasty (THA) and total knee arthroplasty (TKA) is often limited to surgeon-based assessment and patient self-reporting rather than objective measures. However, traditional outcomes may not reliably gauge return of function. The goal of this study was to evaluate and compare an objective measure of postoperative recovery, daily step-count, with patient self-reported outcomes.

Methods: Prospectively, 589 patients used a mobile step-tracking application to record daily steps. Steps were recorded for 4 weeks before surgery and 12 weeks, thereafter. Patient-reported lower extremity functional scale (LEFS) scores were recorded at 1, 6, and 12 weeks, postoperatively. LEFS scores were correlated to weekly median daily steps using the Spearman rank correlation coefficient.

Results: Preoperative median daily steps were 2682 and 1988 for patients undergoing THA and TKA, respectively. Steps for weeks 1, 6, and 12 were 214, 3,170, and 3884 after THA and 153, 1772, and 2311 after TKA, respectively. Step-count demonstrated a weakly positive correlation with LEFS scores. For week 1, the correlation was 0.27 and 0.29 for THA and TKA patients, respectively. For week 6, the correlation was 0.18 and 0.29 for THA and TKA patients, respectively.

Conclusion: Physical function improved over the first 12 weeks as measured by both steps and patient-reported assessments. Postoperative steps weakly correlated with LEFS scores, suggesting patient-reported outcomes may provide only part of the story. Incorporating objective measures may be a valuable addition to the surgeon's armamentarium for monitoring patient recovery.