Glenohumeral translations are only partially restored after repair of a simulated type II superior labral lesion

Abstract

Background: The effect on joint stability of repair of type II superior labrum and biceps anchor lesions is unknown.

Hypothesis: Increased translations of the glenohumeral joint after a simulated type II lesion will be reduced after the lesion is repaired.

Study design: Controlled laboratory study.

Methods: A robotic/universal force-moment testing system was used to simulate load-and-shift and apprehension tests on eight cadaveric shoulders to determine joint kinematics of the shoulder after venting, creation of a type II lesion, and repair of the lesion.

Results: At 30 degrees of abduction, anterior translation of the vented joint in response to an anterior load was 18.7 +/- 8.5 mm and was significantly increased to 26.2 +/- 6.5 mm after simulation of a type II lesion. Repair did not restore anterior translation (23.9 +/- 8.6 mm) to that of the vented joint. The inferior translation that also occurred during application of an anterior load was 3.8 +/- 4.0 mm in the vented joint and increased significantly to 8.5 +/- 5.4 mm with a simulated type II lesion. After repair, the inferior translation decreased significantly to 6.7 +/- 5.3 mm.

Conclusions: Repair of a type II lesion only partially restored glenohumeral translations to that of the vented joint.

Clinical relevance: Surgical techniques including improved repair of passive stabilizers injured in the type II lesion should be considered.