Biomechanical evaluation of a hybrid suture and anchor-based hip capsular repair. (January 2021) - Degen, Ryan M.
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. Highlights: In complex or revision cases, primary capsular repair is not always feasible A hybrid suture and anchor-based capsular repair can be performed This hybrid suture and anchor repair performs equally to an all-suture based repair Both repair types restore joint translation, but rotation at 90° remains increased