A biomechanical comparison of two suture anchor configurations for the repair of type II SLAP lesions subjected to a peel-back mechanism of failure.

PURPOSE: The purpose of this study was to biomechanically compare 2 different suture anchor configurations in the repair of type II SLAP lesions.

METHODS: Standardized type II SLAP lesions were created in 8 matched pairs of cadaveric shoulders. Two different suture anchor configurations were used to repair the type II SLAP lesions. Group 1 SLAP lesions were repaired with 1 suture anchor placed at the anterior border and a second suture anchor placed at the posterior border of the biceps tendon. Group 2 SLAP lesions were repaired with 2 suture anchors placed posterior to the biceps tendon. Biomechanical testing was conducted in 1 direction. A posterior-directed force, in the plane of the glenoid, simulated the peel-back mechanism that occurs during the late cocking phase of throwing. Biceps-labral complex displacement from the glenoid was measured with 2 miniature displacement transducers. Repair failure (2 mm of posterior labral displacement), ultimate failure, and construct stiffness were measured for each specimen.

RESULTS: The mean load to repair failure was 43.66 N in group 1 and 40.70 N in group 2. The mean load to ultimate failure was 156.28 N in group 1 and 162.06 N in group 2. The mean construct stiffness was 25.91 N/mm in group 1 and 30.28 N/mm in group 2. The differences between the 2 groups were not statistically significant in terms of repair failure, ultimate failure, and construct stiffness.

CONCLUSIONS: When repaired type II SLAP lesions were subjected to a posterior vector load to simulate the peel-back mechanism, the 2 suture anchor configurations were biomechanically equivalent.

CLINICAL RELEVANCE: Placement of an anterior suture anchor could, theoretically, tension the anterior capsulolabral structures via the superior and middle glenohumeral ligaments to the superior labrum. The results of this study suggest that there is no biomechanical advantage to placing an anterior suture anchor and so the use of 2 posterior suture anchors may be preferable in the repair of type II SLAP lesions.