Thicker Porcine Xenografts Provide Superior Biomechanical Stability Compared With Single‐Layer Human Dermal Allografts in Superior Capsular Reconstruction

PURPOSE: To compare the biomechanical effectiveness of superior capsular reconstruction (SCR) using a thick porcine dermal xenograft versus a standard human dermal allograft (HDA) in restoring shoulder stability and motion in irreparable rotator cuff tears. METHODS: Eight cadaveric shoulders were tested in four sequential conditions: intact, massive rotator cuff tear, SCR with xenograft, and SCR with single-layer HDA. Testing was performed at 0°, 20°, and 40° of glenohumeral abduction with 30° of external rotation under simulated balanced and unbalanced muscle loading conditions. Outcome measures included humeral rotational range of motion (ROM), superior humeral head translation, and subacromial contact pressure. RESULTS: Mean graft thickness was 4.8 ± .2 mm for xenografts and 2.1 ± .1 mm for allografts (P < .001). Xenograft SCR preserved physiologic rotational ROM. In contrast, allograft SCR resulted in increased internal rotation at 20° (P = .012) and 40° of abduction (P = .001) and greater total ROM at 0° and 40° (P = .007) compared with the intact state. Massive tears significantly increased superior humeral translation at all angles (P < .05). Xenograft SCR restored translation to near-intact levels at 0° and 40°, whereas allograft SCR showed persistently elevated translation at 0° and 20° (P < .05). At all angles, superior translation was significantly lower with xenograft than allograft (P < .05). Subacromial pressure was highest in the massive tear condition (P < .001). Both grafts reduced pressure, however xenograft SCR resulted in lower values than allograft at 20° (P = .003) and closely matched intact values at all angles. CONCLUSIONS: In a cadaveric model of irreparable rotator cuff tear, SCR using a thick porcine dermal xenograft more effectively restored shoulder biomechanics compared with a single-layer HDA. These advantages may relate to the xenograft's greater initial thickness and associated mechanical properties. CLINICAL RELEVANCE: In SCR for irreparable rotator cuff tears, graft selection is a critical factor influencing biomechanical performances. This cadaveric study suggests that a porcine dermal xenograft with sufficient thickness may provide superior restoration of glenohumeral stability and joint mechanics compared with a commonly used single-layer HDA. These findings highlight the importance of graft thickness and mechanical integrity in optimizing SCR outcomes and may inform surgical decision-making in clinical practice.