Biomechanics of Failed Rotator Cuff Repair: How to Optimize Anchor and Suture Placement

Most failures of rotator cuff repair occur at the tendon-suture junction, followed by anchor pullout. Various types of suture-tendon construct have been introduced to improve the strength. Meta-analyses have shown that double-row repair techniques are biomechanically superior to single-row repairs although there is no difference in the clinical outcome. Various reinforcement procedures such as adding augmentation sutures at the medial row, doubling the number of sutures, or using tapes wider than sutures seem to be effective in making the repair construct more durable. Information about triple-row repair is too limited to make any conclusions. In order to avoid anchor pullout, it is useful to estimate the anchor pullout strength using the CT data of the proximal humerus prior to surgery. A suture anchor should be inserted perpendicular to the bony surface to obtain the maximum pullout strength based on all the biomechanical studies and proper interpretation of the “deadman theory.”