Update on Repair Biomechanics for Rotator Cuff Fixation

Biomechanical testing is a useful tool to compare rapidly evolving rotator cuff repair techniques. The methods of biomechanical testing have also evolved to better simulate the postoperative environment and actual failure modes. Initial biomechanical tests used a single load to failure of the repair, which poorly simulated the postoperative environment. Cyclic loading in a single direction was then introduced and improved our understanding of failure. Most recently, cyclic loading in multiple directions has been performed and better simulates the postoperative environment. The mechanics of the tendon repair attachment that may influence the biology of healing has also been evaluated. This includes the restoration of the native insertional footprint, pressurized contact of the tendon to the footprint, and interface motion at the footprint between the tendon and the bone. Because different anchor designs and configurations, suture materials, and suture passage techniques are rapidly changing, it is important to keep in mind that careful and high-quality biomechanical testing is a prerequisite for widespread clinical application.