Usefulness of the Kinect‐V2 System for Determining the Global Gait Index to Assess Functional Recovery after Total Knee Arthroplasty

Objective The Korean Knee Society (KKS) score is used for functional evaluation during follow‐up after total knee arthroplasty (TKA), but it is time‐consuming to measure and is limited by its subjective nature. We investigated whether the global gait asymmetry index (GGA) that can be obtained using the Kinect‐V2 system could overcome the KKS limitations. Methods Forty‐three patients who underwent TKA from January 2019 to December 2019 were included. Postoperatively, regular follow‐up was performed at 2, 4, 6, 8, and 12 weeks, and at 4, 6, and 12 months. At each follow‐up visit, the KKS was measured, and the walking path was followed with six Kinect‐V2 systems. After allowing the participants to walk naturally, the range of motion of each joint of the lower extremity and GGA were obtained. Changes in the KKS and GGA scores and measurement times were investigated until the final follow‐up. A statistical model was made to predict the KKS from the GGA score using data at all observed time points, and analysis of variance (ANOVA) with Turkey's post‐hoc tests and Pearson correlation tests were used for evaluation. Results Both the KKS and GGA scores improved significantly from 4 weeks postoperatively until the final follow‐up. The measurement time was significantly shorter for the GGA (9.3 ± 1.4 min) than for the KKS (32.4 ± 9.2 min; P