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Rotator cuff tears are a common source of shoulder pain and disability.1–3 The incidence of rotator cuff repair is approximately 98 per 100,000 individuals.2 Failure rates after arthroscopic repair range from 13% to 92%.4–6 With newer high-strength sutures and anchors, failure is typically seen as a result of the loss of integrity of the bone to tendon interface.1 Cho et al7 further described the tendency of the rotator cuff to retear at the tendon insertion site (type 1) or at the myotendinous junction (type 2) depending on the repair construct. Regardless of the strength of the construct, there are often retears of the pathologic tendon that result from replacement of type 1 collagen with type 3 collagen, an overall decrease in fibroblasts, and neovascularization.1 The normal rotator cuff bone-tendon interface (enthesis) includes a transition from tendon to bone on a continuum of mechanical properties. The transition proceeds from normal tendon to noncalcified fibrocartilage, to calcified fibrocartilage, and finally to bone.8 Even with a successful rotator cuff repair, it is likely that the normal enthesis is not properly restored, with the bone-tendon junction consisting of tendon, noncalcified fibrocartilage, and bone. If the calcified fibrocartilage remains absent, this may result in eventual failure, leading to worse clinical outcomes.1,6
Efforts have been made to enhance the healing of the enthesis, including microfracture at the rotator cuff footprint, platelet-rich plasma injections, and administration of mesenchymal stem cells.1 One novel approach is to provide a scaffold between the tendon and bone to augment the movement of cells across the gap between the two. The BioWick anchor (Zimmer-Biomet) is an interpositional scaffold-anchor that has a PLGA (poly(llactide-co-glycoside)) scaffold attached to a standard anchor. This implant was designed to address the proposed issue of biologic rotator cuff healing as described above. Once the anchor is deployed, the scaffold lies on the surface of the tuberosity and remains attached to the anchor. The repaired tendon then lies on the scaffold. This juxtaposed scaffold is intended to act as a conduit for cells growing from the bone to the tendon.9
The purpose of this study was to determine the effectiveness of this scaffold-anchor with respect to retear rates and patient function after arthroscopic rotator cuff...