Biomechanical evaluation of a hybrid suture and anchor-based hip capsular repair

Abstract Background Hip capsulotomies, performed routinely during hip arthroscopy, can contribute to adverse joint kinematics. Direct repair is not always feasible. Therefore, the aim of this study was to evaluate the biomechanics of a conventional all-suture repair versus a hybrid suture and anchor-based capsular repair. Methods Nine paired (n = 18) hips were tested on a joint-motion simulator, utilizing optical trackers to capture kinematic data. Pairs were randomly allocated to capsular repair type and tested as (1) intact, (2) after T-capsulotomy, and (3) repair each at 0°, 45°, and 90° flexion. Internal and external rotation torques and abduction/adduction torques of 3 N·m were applied and rotational range of motion and joint translations recorded. Findings At 0°, following repair there were no significant differences in joint rotation or translations between repairs (p > 0.134). At 45°, both repair types restored motion to near intact values, with no significant differences between groups. Similarly, there were no significant differences in joint translations between repairs. At 90°, both types of capsular repair failed to restore rotational range of motion, with persistent increases in motion (47.0 ± 16.7°) compared to the intact condition (44.1 ± 15.8°, p = 0.006); however, there were no significant differences between repair groups. There were no significant differences in joint translations between repairs. Interpretation Use of a hybrid repair produced comparable joint rotation and translation under all testing conditions as an all-suture repair. As such, this technique represents a viable option for capsular repair where proximal capsular tissue is deficient.