Editorial Commentary: Mechanics Versus Biology: Both Are Relevant Principles in Understanding Superior Capsular Reconstruction.

Abstract The topic of superior capsular reconstruction remains controversial. Whereas identifying the best time-zero graft configuration for this procedure remains important, the success or failure of the procedure will be dependent on the biology, not just the bench performance. Any conforming object placed in the subacromial space at time zero could center the humeral head and decrease superior translation compared with a massive rotator cuff tear but may not restore translation to normal. It does appear that a thicker graft is better in this regard, but how much thicker is better is unclear. Most of all, whether the mechanical benefits of a thicker graft will be offset by a thicker and potentially less biologically compatible construct is also unclear. In most orthopaedic settings, autografts remain consistently superior to allografts. The contrast in results may be better explained by biology, and the excellent superior capsular reconstruction results reported with autograft have not been replicated universally with dermal allograft.