Editorial Commentary: Fascia Lata Allograft for Shoulder Superior Capsular Reconstruction: In the Fight Over Optimal Graft Choice for Irreparable Rotator Cuff Tears, Superior Capsular Reconstruction Proponents May Be Changing Their Gloves.

Optimal treatment of irreparable rotator cuff tears is still debated. Proponents of the superior capsule reconstruction (SCR) have previously used fascia lata autograft and acellular dermal allograft. Interest is growing in using fascia lata allograft as a new graft material. Well-designed biomechanical studies are important to understand the mechanical properties of the superior capsular tissue and fascia lata allograft. Recent biomechanical research shows that fascia lata allograft has similar initial stiffness (over the first 2 mm) and ultimate load compared to the native superior capsule. That said, ultimate load is the load at which a construct fails, whereas the yield point is the load on the stress-strain curve at which a material transitions from elastic to plastic deformation. In the shoulder where the SCR, for example, is going to be repetitively loaded, it is potentially more meaningful to talk about the yield point in order to stay within the elastic range. Using this framework, the yield point for fascia lata allograft is approximately one third the yield point of native capsular tissue. Additionally, "initial" stiffness is not the entire story. At greater loads, fascia lata allograft has higher displacement compared to native tissue. Of importance, fascia lata allograft failed by sutures slowly cutting through the allograft tissue; this may represent a limitation of the construct that could be addressed using stitch configurations resistant to cut through. Fascia lata allograft is a promising solution for SCR. Biomechanical studies require nuanced interpretation, and most of all, do not evaluate clinical healing.