Editorial Commentary: Biomechanical Investigation of Superior Capsule Reconstruction Requires Meticulous Methods.

One of the treatment options for a massive irreparable rotator cuff tear is superior capsule reconstruction (SCR). Biomechanically, SCR depresses and centers the humeral head on the glenoid so that the remaining rotator cuff muscles and the deltoid can provide function. Therefore, in SCR, graft characteristics such as graft type, graft thickness, and graft tension are the critical parameters contributing to the biomechanical effectiveness. SCR was originally developed with fascia lata autografts, but in the United States, the most popular graft used is acellular human dermal allograft. Both have been clinically successful with their own advantages and disadvantages. The effects of graft thickness on SCR are fairly well understood, and using a thicker graft provides 2 distinct advantages. The first is stiffness; the thicker the graft, the stiffer the graft. The second is the spacer effect, which helps to maintain the acromiohumeral distance. A key caveat is that a double-layer graft is fundamentally different from a single-layer graft, and the number and location of stitches strongly influence the biomechanical characteristics. SCR biomechanical studies may be applied in concept, but clinical application will require detailed information on the graft preparation strategy to control graft thickness and tension.