A randomized controlled trial comparing controlled active motion and early passive mobilization protocols for rehabilitation of repaired flexor tendons in zone II

Background: Flexor tendon injuries in zone II of the hand pose serious clinical complications due to the high risk of adhesion formation and suboptimal clinical outcomes, although controlled active motion (CAM) and early passive mobilization (EPM) are standard protocols used during rehabilitation. Objective: This randomized trial compared functional outcomes between CAM and EPM systems after zone II flexor tendon repair. Methods: Forty patients with entire zone II flexor digitorum profundus and superficialis tears were randomly assigned to either the CAM or EPM protocol for 12 weeks’ rehabilitation. Total active motion (TAM), grip strength, and disability of the arm, shoulder, and hand (DASH) scores were assessed in the 6th and 12th week after the repair. Two-way mixed ANOVA was used to determine the effect of the treatment regarding the type of protocol and time within and between groups, as well as, Cohen's d was used to calculate the effect size. Results: There was a significant improvement over time in both groups for all measured outcomes (p < 0.001). However, CAM showed superior results than EPM across all time points (6th and 12th week); for TAM (p < 0.05, Cohen's d =11.8 and 9.9), grip strength (p < 0.05, Cohen's d = 7.97 and 9.7), and DASH score (p < 0.05, Cohen's d = 5.8 and 5.5). By 12 weeks, 80% of CAM patients achieved an “excellent” rating according to the Strickland formula of the TAM grading compared with 55% for the EPM group. Conclusion: While both CAM and EPM protocols improve functional status after zone II flexor tendon repair, CAM confers a distinct early advantage in a digital range of motion and manual function compared with EPM. These data support the preferred adoption of the CAM rehabilitation approach after area II flexor tendon surgical repair.