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.