Increased Bite Distance From the Edge Lowers Risk of Pullout of Simple Sutures from Acellular Dermal Allograft

Purpose: To investigate whether pullout strength in the acellular dermal allograft matrix (ADM) used for superior capsule reconstruction depends on the distance from the edge of the graft. Methods: ADM used for superior capsule reconstruction was obtained and cut into 30 squares. Two sutures were placed through the center of each graft by using a loaded Keith needle and forming a simple stitch. The grafts were divided into 3 groups of 10 grafts with a distance of 5 mm, 10 mm or 15 mm from the closest edge of the graft, respectively. The grafts were then preloaded to 5 N and pulled to failure at a rate of 12 mm/s on an MTS 858 MiniBionix servohydraulic mechanical test frame. The load to failure was recorded as well as the stiffness of each graft. Results: The mean load to failure was 34.5 N (SD 7.89) for the 5 mm grafts, 31.7 N (SD 5.99) for the 10 mm grafts, and 66.2 N (SD 18.4) for the 15 mm grafts. There was a significant difference (< 0.0001) between the large grafts (15 mm) and the 2 smaller grafts (10 mm, 5 mm). There was no significant difference in stiffness between the groups of graft (P 0.40). Conclusion: Placing the suture at least 15 mm from the edge of the graft increases the graft's ultimate yield strength to suture pullout. Clinical Relevance: The depths of the suture in ADM could improve pullout strength for constructs of superior capsular reconstructions.