Strength of Single- Versus Double-Anchor Repair of Type II SLAP Lesions: A Cadaveric Study

Purpose: This study was designed to examine whether there was a difference in pullout strength along with the mode of failure between I suture anchor and 2 suture anchors. Methods: Ten matched pairs of cadaveric shoulders were used in the study. A type II SLAP lesion, according to the classification of Snyder et al., was created. In 10 shoulders I anchor with 2 sutures was used to repair the lesion. In the other group of 10 matched shoulders, fixation was done with 2 anchors, with each anchor having only I suture. An Instron servohydraulic test machine (Instron, Canton, MA) was used to pull the long head of the biceps tendon until failure occurred. Results: The single-anchor group failed at a mean load of 278.5 +/- 101.5 N. The double-anchor group failed at 242.5 +/- 96.5 N. A paired 2-sample Student t test showed that there was no significant difference in pullout strength between the 2 groups (P = .090). The most common mode of failure was soft-tissue failure. There was I anchor pullout in the single-anchor group and 2 anchor pullouts in the double-anchor group. Conclusions: The results of this study imply that using I anchor with 2 sutures is biomechanically equivalent to 2 anchors with I suture each for repairing type II SLAP lesions. Clinical Relevance: Using I suture anchor is sufficient to repair a type II SLAP lesion.