Tear pattern after superior capsular reconstruction using an acellular dermal matrix allograft

Abstract

Background: The healing rate and tear pattern of grafts in superior capsular reconstruction (SCR) using acellular dermal matrix (ADM) allograft are poorly understood, and clinical results based on the graft status remain controversial.

Methods: Fifty-one consecutive patients undergoing arthroscopic SCR with ADM between October 2017 and February 2020 were enrolled. Range of motion, strength, and the visual analog scale pain (PVAS) score, American Shoulder and Elbow Surgeons (ASES) score, and Constant score were evaluated preoperatively and at the last follow-up. Postoperative magnetic resonance imaging was performed in all patients and was obtained at least 6 months (mean, 8.9 ± 3.6 months) after surgery. The graft tear status was analyzed on magnetic resonance imaging, and the numbers of patients who achieved the minimal clinically important difference and patient acceptable symptomatic state were analyzed to determine the differences in outcome according to graft tear status.

Results: The range of motion and clinical results improved at a minimum of 1 year (mean, 18 ± 5.4 months), whereas strength in forward flexion and external rotation did not (P = .676 and P = .995, respectively). The graft was intact in 36 of 51 patients (70.6%), 9 patients (17.6%) showed an incomplete graft tear with maintained continuity (partial graft rupture at 1 anchor on either the glenoid or humeral side), and 6 patients (11.8%) showed complete graft rupture (5 on the glenoid side and 1 on the humeral side). In cases with a tear (either incomplete or complete), the odds of achieving the minimal clinically important difference for the PVAS score (P = .047) and ASES score (P = .020) was significantly lower than that of the intact graft. However, when the continuity of the graft was maintained, even in cases with a partial tear, patients who reached the patient acceptable symptomatic state showed significantly higher odds for the PVAS score and trends for the ASES score.

Conclusion: After SCR using ADM, the graft status could be classified as intact, an incomplete graft tear (where the continuity between the glenoid and humerus was maintained), or an complete tear. When the graft continuity was maintained, even in incomplete graft tears, patients were generally satisfied with postoperative pain and function at 1 year following SCR.