Toward Personalized Orthopedic Care: Validation of a Smart Knee Brace.

Introduction: Wearable technology offers a promising solution to advance current rehabilitation strategies for post-operative orthopedic care. The aim of this study was to determine the level of agreement and concurrent validity of a smart knee brace compared to the gold standard measurement system GAITRite for assessing lower limb gait parameters.

Methods: Thirty-four healthy participants were fitted with the smart knee brace (Digital Knee) on their dominant limb. Gait parameters (stride length, stride time, and gait velocity) were measured simultaneously using the Digital Knee and the GAITRite electronic walkway. Two walks were performed at a comfortable speed and two at a fast-walking speed.

Results: At a comfortable walking speed, stride time was moderately valid (ICC = 0.66 s), and stride length and gait velocity demonstrated poor validity (ICC = 0.29; ICC = 0.41). All gait parameters demonstrated poor validity at a fast-walking speed (ICC = -0.16 to -0.01). Bias ranged from -0.08 to 0.28, with more clinically acceptable percentage errors at a comfortable walking speed (14.1-30%) versus at a fast-walking speed (26.4-42.6%). Gait velocity and stride length had substantially higher biases in the fast-walking speed compared to the comfortable walking speed (0.28 ± 0.39 m s vs. 0.02 ± 0.21 m s; 0.15 ± 0.23 m vs. -0.04 ± 0.17 m). Limits of agreement were considered narrower for stride time compared to stride length and gait velocity.

Conclusion: The Digital Knee is a promising approach to improving post-operative rehabilitation outcomes in patients with osteoarthritis. The Digital Knee demonstrated good agreement and moderate concurrent validity for measuring gait metrics at a comfortable walking speed. These findings highlight the opportunity of the wearable sensor as an intervention for post-operative orthopedic care. This was a laboratory-based study; thus, further research is required to validate the wearable sensor in real-world contexts and in patients with knee pathologies. Further, refinement of the algorithm for measuring gait metrics at slow- and fast-walking speed with the Digital Knee is warranted.