Hip Labral and Capsular Repair Are Unable to Restore Distractive Stability in a Biomechanical Model.

PURPOSE: To evaluate the change in hip distractive stability after capsulotomy, labral tear, and simultaneous repair of both structures in a biomechanical model.

METHODS: Ten fresh-frozen human cadaveric hips were analyzed using a materials testing system to measure distractive force and distance required to disrupt hip suction seal after (1) native intact capsule and labrum, (2) 2 or 4 cm interportal capsulotomy (IPC), (3) labral tear, (4) T extension, (5) labral repair, (6) T extension repair, and (7) IPC repair. Each specimen was retested at 0° flexion, 45° flexion, and 45° flexion with 15° internal rotation.

RESULTS: A significantly higher distractive force was required to rupture the suction seal in the intact condition compared to an IPC (P = .012, confidence interval (CI): 4.9, 42.4), IPC, labral tear (P = .002, CI: 11.3, 49.4), IPC, labral tear, T extension (P = .001, CI: 13.9, 51.5), IPC, labral repair, T extension (P < .001, CI: 20.8, 49.7), IPC, labral repair, T extension repair (P = .002, CI: 12.5, 52.4), and IPC repair, labral repair, T extension repair (P = .01, CI: 5.8, 46.1). The IPC condition required higher distractive force in isolation compared to when combined with a labral tear (P = 0.14, CI: 1.2, 12.0), T extension (P = .005, CI: 2.8, 15.3), or labral repair (P = .002, CI: 4.4, 18.8).

CONCLUSIONS: The distractive resistance of an intact hip capsule and labrum was not restored once the soft tissues were violated, despite labral repair with a loop technique and capsular repair with interrupted figure-of-eight sutures.

CLINICAL RELEVANCE: Time zero complete capsular repair with concomitant labral repair may not be adequate to restore distractive hip stability following hip arthroscopy, reinforcing the use of post-operative precautions in the early post-operative period.