Work

Real-World Functional Gait Recovery Trajectories After Total Hip and Total Knee Arthroplasty via Smartphone Sensors: Observational Longitudinal Study

Year: 2026

Type: article

Abstract: Background: Recovery after total hip arthroplasty (THA) and total knee arthroplasty (TKA) is typically assessed with infrequent clinic-based evaluations that may not reflect patients' everyday mobility. Smartphone inertial sensors enable scalable, repeated gait measurement in real-world settings, but the extent to which prompted walking tests reflect daily life walking during recovery is not well defined. Objective: The objective of this study was to characterize week-by-week recovery trajectories after THA and TKA using high-frequency smartphone sensor data and quantify the difference between prompted in-app walking tests and passive daily life background walking. Methods: We analyzed longitudinal smartphone-based gait measurements from 735 patients (THA, n=350; TKA, n=385) who underwent unilateral surgery between July 2022 and October 2025. Nine spatiotemporal gait parameters were monitored over the first 15 postoperative weeks across 2 conditions: prompted "in-app" walks and passively captured "background" walks. Recovery trajectories were evaluated using Kaplan-Meier time-to-baseline analyses, linear mixed-effects models, and comparison of late-stage plateau levels (weeks 11-15) using estimated marginal means of the models. Results: Across all parameters, THA patients returned to preoperative baseline levels faster than TKA patients, with mean trajectories generally approaching baseline by week 4 for THA versus weeks 6 to 8 for TKA. Linear mixed-effects models showed that surgical procedure type significantly influenced recovery trajectory for all parameters except single support of the unaffected leg. All gait parameters except stance asymmetry and single support of the unaffected leg exhibited persistent differences through the late-recovery plateau (weeks 11-15). We also compared prompted "in-app" walks with passively captured background walking. Prompted and passive walking showed systematic divergence in both THA and TKA; prompted assessments generally indicated faster or more complete return to baseline than passive daily life walking. Finally, preoperative gait level was strongly associated with postoperative trajectories, with baseline-stratified analyses showing distinct patterns of recovery between groups. Conclusions: High-frequency smartphone gait assessment quantifies procedure-specific recovery dynamics and demonstrates that prompted tests and passive daily life measurements capture distinct, noninterchangeable functional signals. Parameters from prompted walks plateaued while those from passively captured walks were still changing; prompted testing alone therefore captures only one component of returning function, highlighting the additional information that passive, real-world gait monitoring can provide.

Source: JMIR mhealth and uhealth

DOI: 10.2196/97657

Authors: Levi S Teitz, Einat Granot-Hershkovitz, Pei-An Lee, On-Yee Lo, Brad Manor, Yuval Y Naveh

Institutions: Beth Israel Deaconess Medical Center, Harvard University, Hebrew SeniorLife

Language: English

Topic: Total Knee Arthroplasty Outcomes

Subfield: Surgery

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: gold

Estimated APC paid: $2,850