Suture Tape–Reinforced Human Dermal Allograft Used for Superior Capsule Reconstruction Demonstrates Improved Ability to Withstand Elongation

Abstract

Purpose To investigate the potential for a suture tape–reinforcement technique to prevent elongation with repetitive use of a human dermal (HD) allograft traditionally used for superior capsule reconstruction in a biomechanical model. Methods Using 8 scapulae and humeri Sawbones models, the standard superior capsule reconstruction was performed using 8 HD allografts. Four grafts were tested in the native state, whereas 4 were tested using reinforcement. Allografts were reinforced using suture tape in a running 360° fashion around the allograft borders, maintaining 5 mm of space from the edges. Allografts were measured pre- and postdynamic testing for length, width, and thickness. All specimens were affixed to a materials testing machine that allowed for allograft orientation in a longitudinal plane throughout testing. Specimens were preloaded to 10 N and then cyclically loaded to 100 N at a rate of 15 mm/s for 30 cycles. Results After dynamic, cyclic loading, suture tape–reinforced allografts experienced a significantly smaller percent change in anterior length (6.36% vs 14.50%, P = .013), posterior length (6.00% vs 13.68%, P = .002), medial width (5.80% vs 21.05%, P = .001), lateral width (5.45% vs 19.29%, P < .001), medial thickness (4.38% vs 17.93%, P = .005), central thickness (7.03% vs 16.11%, P = .026), and lateral thickness (4.55% vs 20.80%, P < .001). Linear stiffness values obtained for suture tape –reinforced allografts were significantly greater than those for native allografts when measured at cycles 1 (21.18 ± 1.03 N/mm vs 17.69 ± 1.91 N/mm, P = .02), 15 (29.90 ± 1.45 vs 24.93 ± 2.79, P = .03), and 30 (32.13 ± 1.98 N/mm vs 25.72 ± 3.01 N/mm, P = .01) of dynamic testing Conclusions The suture tape–reinforcement technique described decreased HD allograft elongation, maintained graft thickness, and improved linear stiffness values following uniplanar cyclic loading in a biomechanical Sawbones model. Clinical relevance Suture tape reinforcement of the HD allograft could serve as one strategy to overcome the issue of allograft elongation with time following superior capsule reconstruction.

Biomechanical Comparison of Synthetic Polytetrafluoroethylene (PTFE) vs Human Dermal Allograft (HDA), 2 vs 3 Glenoid Anchors, and Suture vs Minitape in Superior Capsule Reconstruction

“…While various morphological patterns of graft failure exist [6], several clinical studies have identified through postoperative magnetic resonance imaging that graft failures most commonly failed at the glenoid interface, followed in frequency by intrasubstance tearing [3,9,12,18,39]. A number of authors used 2 glenoid anchors as described in both clinical and biomechanical studies by Mihata et al [26,28], whereas others used 3 glenoid anchors [7,19,36,44]. Pogorzelski et al [38] found that SCR with 3 glenoid anchors had greater pullout strength than SCR with 4 anchors in 36 cadaveric shoulders.…”