Recovery Curve for Patient Reported Outcomes and Objective Physical Activity After Primary Total Knee Arthroplasty-A Multicenter Study Using Wearable Technology.

BACKGROUND: This study aimed to describe the trajectory of recovery based on patient-reported outcomes (PROs) and objective metrics of physical activity measures over the first 12 months post-total knee arthroplasty (TKA). METHODS: In total, 1,005 participants who underwent a primary unilateral TKA surgery between November 2018 and September 2021 from a multisite prospective study were analyzed. Generalized estimating equations were used to evaluate PROs and objective physical activity measures over time. RESULTS: All Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS JR), EuroQol-5D (EQ-5D), and steps per day scores were greater than preoperative scores (P < .05). The flights of stairs per day, gait speed, and walking asymmetry all declined at 1 month (all, P < .001). However, all subsequent scores improved by 6 months (all, P < .01). The greatest clinically important differences from previous visit in KOOS JR (ß = 18.1; 95% Confidence Interval (CI) = 17.2, 19.0), EQ-5D (ß = 0.11; 95% CI = 0.10, 0.12), steps per day (ß = 1,169.3; 95% CI = 1,012.7, 1,325.9), gait speed (ß = -0.05; 95% CI = -0.06, -0.03), and walking asymmetry (ß = 0.00; 95% CI = -0.03, 0.03) were observed at 3 months. CONCLUSION: The KOOS JR, EQ-5D, and steps per day measures showed earlier improvements than other physical activity metrics, with the greatest magnitude of improvement within the first 3 months post-TKA. The greatest magnitude of improvement in walking asymmetry was not observed until 6 months, while gait speed and flights of stairs per day were not observed until 12 months. This data may further help provide expectation setting information to patients before surgery, and may aid in identifying outliers to the normal recovery curve who may benefit from targeted interventions.