Repeated Knee Flexion Maneuvers after Wound Closure Improve Early but not Long-Term Knee Flexion Following Simultaneous Bilateral Total Knee Arthroplasty: A Double-Blinded Randomized Controlled Trial.

Restoring knee joint range of motion is a key objective after total knee arthroplasty (TKA), as it strongly influences functional outcomes. This study evaluated the efficacy of repeated knee flexion maneuvers performed after wound closure on clinical outcomes following one-stage simultaneous bilateral TKA. In this prospective, double-blinded, randomized controlled trial, 46 patients (92 knees) were randomized to determine the intervention side, which involved 15 repetitions of deep knee flexion and full extension after wound closure. The contralateral knee served as the control. Outcomes included active knee flexion angles, extension lag (EL), and pain intensity measured by the visual analog scale (VAS). Active knee flexion angles were significantly greater in the intervention group on postoperative day 1 (mean difference of 6.9 degrees, 95% confidence interval [CI]: 3.8-10.0, p < 0.001), day 2 (mean difference of 4.8 degrees, 95% CI: 1.7-8.0, p = 0.003), day 3 (mean difference of 6.3 degrees, 95% CI: 3.1-9.4, p < 0.001), and at 2 weeks (mean difference of 5.4 degrees, 95% CI: 2.3-8.6, p < 0.001). The EL was lower in the intervention knee, with statistical significance observed on postoperative day 1. VAS pain scores were also significantly lower in the intervention knee at 2 weeks postoperatively, although the difference remained below the clinically meaningful threshold. Repeated knee flexion maneuvers after wound closure improved active knee flexion during the first 2 weeks after TKA. However, these differences did not persist beyond the early postoperative period, and final knee flexion outcomes were similar between groups. This study was registered in the Thai Clinical Trials Registry database (no. TCTR20230314002).