Preoperative Decline and Postoperative Recovery of Wearable-Derived Physical Activity Over a Four-Year Perioperative Period in Total Knee and Hip Arthroplasty: Evidence from the All of Us Research Program

2026-03-05

AI Summary

This study addresses the lack of systematic characterization of longitudinal physical activity trajectories in patients undergoing total knee (TKA) and total hip arthroplasty (THA). Leveraging the “All of Us” program, we integrated electronic health records with Fitbit step-count data and applied piecewise linear mixed-effects models to analyze activity changes over a four-year window. Kaplan–Meier and Cox regression models were employed to assess recovery timelines and associated factors. Using long-term wearable data, we reveal a preoperative progressive functional decline and a three-phase postoperative recovery pattern. The median times to recover to recent and distant preoperative baseline activity levels were 13 and 22 weeks, respectively. Higher preoperative activity levels were strongly associated with greater likelihood of returning to habitual activity, underscoring the critical role of preoperative functional reserve.

Technology Category

• Planning, Routing, and Scheduling: Activity and Plan Recognition
• Humans and AI: Human-Aware Planning and Behavior Prediction
• Data Mining & Knowledge Management: Representing, Reasoning, and Using Provenance, Trust

Application Category

• User Modeling, Personalization and Recommendation: Studies of user behavior, including longitudinal effects of personalized systems
• Graph Algorithms and Modeling for the Web: Representation, reconstruction, and subgraph or motif discovery in Web-related graphs
• Security and Privacy: Large-scale security measurements

Abstract

Total knee arthroplasty (TKA) and total hip arthroplasty (THA) improve symptoms in end-stage osteoarthritis, yet long-term objective characterization of perioperative physical activity trajectories remains limited. We conducted a longitudinal observational study within the All of Us Research Program dataset, linking electronic health records with continuous Fitbit-derived step count data over a four-year perioperative window (two years before and two years after arthroplasty). Piecewise linear mixed-effects models characterized preoperative declines and postoperative recovery trajectories, and time-to-recovery was evaluated using Kaplan-Meier curves and Cox proportional hazards models under remote and immediate preoperative physical activity baseline definitions. Among 238 participants (147 TKA; 91 THA), both procedures exhibited progressive preoperative decline with distinct procedure-specific patterns and staged postoperative recovery: rapid improvement during weeks 1-6, decelerating gains through weeks 7-19/20, and subsequent stabilization through week 104. Recovery to remote and immediate baselines differed in timing (median 22 vs 13 weeks) and associated predictors. Higher immediate preoperative activity was associated with greater likelihood of recovery to habitual activity levels, underscoring the relevance of preoperative functional reserve and surgical timing. These findings demonstrate the potential of long-term wearable monitoring to refine assessment of functional outcomes, guide recovery expectations, and support perioperative management.

Problem

• total knee arthroplasty
• total hip arthroplasty
• physical activity
• perioperative period
• wearable monitoring

Innovation

• wearable monitoring
• perioperative physical activity trajectories
• piecewise linear mixed-effects models
• functional recovery
• preoperative functional reserve