Daily physical activity following unicompartmental knee arthroplasty: A pilot study

Purpose

The purpose of this study was to understand how objective measures of daily activity change following unicompartmental knee arthroplasty (UKA). Objective data on post-operative changes in daily physical activity following UKA are limited, highlighting the need for studies using wearable technologies to provide real-time assessments of recovery.

Methods

This pilot study included a secondary analysis of a prospective study of 33 consecutive UKA patients, with data collected using an Apple Watch and a digital care management application. Objective metrics, including step count, steadiness, standing duration and performance on the six-minute walk test, were analyzed at different post-operative time points. Descriptive statistics and the Wilcoxon signed-rank test were used for analysis.

Results

Post-operatively, there was a significant increase in daily step count at 6 weeks (p = 0.017), 6 months (p < 0.001) and 12 months (p = 0.0018). Steadiness improved significantly at 6 months (p = 0.049) and 12 months (p = 0.039) post-operatively. Standing duration increased significantly at all the post-operative time points (p < 0.001). Gait speed did not show significant changes post-operatively. The estimated six-minute walk test distance improved significantly at 6 months (p = 0.027) and 12 months (p = 0.031) post-operatively.

Conclusion

The study findings suggest that UKA improves daily physical activity levels, reflected by enhanced mobility and function. While gait speed did not significantly change, improvements in step count, steadiness, standing duration and the six-minute walk test distance indicate enhanced functional capacity and endurance post-operatively. The study highlights the benefits of UKA in improving functional outcomes in patients with knee osteoarthritis. Further research with larger sample sizes and longer follow-ups is warranted to confirm these findings.

Levels of Evidence

II.