Wearable health technology finds improvements in daily physical activity levels following total knee arthroplasty: A prospective study

PURPOSE: Wearable technologies, like the Apple Watch, offer new possibilities for collecting objective data on physical activity post-operatively following total knee arthroplasty (TKA). This study aims to describe changes in daily physical activity levels using objective metrics over different time points following TKA. METHODS: This study analyzed data from a prospective cohort of 152 patients undergoing a unilateral TKA. Patients wore an Apple Watch and used a digital care management application for data collection. Step count, steadiness, standing duration, gait speed and performance on a 6-min walk test were collected from Apple HealthKit at multiple time points: pre-operative, 6 weeks post-operatively, 6 months post-operatively and 12 months post-operatively. Statistical analyses were performed using R software, including descriptive statistics and paired t tests to compare outcomes at different time points post-operatively. RESULTS: Participants demonstrated significant improvements in daily physical activity levels over the course of 12 months post-operative. At 6 months post-operative, participants showed the highest average daily step count (mean ± SD: 5293 ± 236 steps; p < 0.001), with improvements persisting at 12 months post-operative (5180 ± 260 steps; p < 0.001) compared to preoperative values. Gait speed increased from 0.88 ± 0.01 m/s preoperatively to 1.01 ± 0.01 m/s (p = 0.006) at 12 months post-operative. Standing hours increased from 9.99 ± 0.30 to 11.47 ± 0.31 h at 6 months post-operative and persisted. Steadiness and the estimated 6-minute walk test showed recovery trends, though variability remained at 12 months post-operative, suggesting the need for additional longitudinal assessment CONCLUSION: This study provides one of the first longitudinal analyses of post-operative functional recovery using Apple HealthKit, offering continuous real-world gait and activity tracking beyond traditional patient-reported measures. These findings highlight the value of wearable technology in monitoring post-operative activity and offering insights into TKA recovery patterns. The study suggests a critical recovery window at 6 months post-operative and emphasizes the need for ongoing support to maintain improvements. The integration of wearable technology in post-operative monitoring offers a promising approach to tracking patient progress and optimizing functional outcomes following TKA. LEVEL OF EVIDENCE: Level II.