Biomechanical and clinical evaluations of superior capsular reconstruction using autologous tendon for irreparable rotator cuff tear.

Introduction: To evaluate the biomechanical and clinical outcomes of superior capsular reconstruction (SCR) with autologous tendon (AT) for the irreparable rotator cuff tears (IRCTs). Methods: Ten fresh-frozen human upper limb specimens were used to create three models (intact, rotator cuff-deficient, and reconstruction). Superior translation of the humeral head and subacromial pressure were measured at different abduction angles under standardized loading. Mechanical comparability between tendons was also evaluated by measuring cross-sectional area and basic tensile properties. For clinical evaluation, a prospective case series of nine patients with IRCTs tears who underwent SCR with AT was conducted. Shoulder joint range of motion, American Shoulder and Elbow Surgeons (ASES), and Constant-Murley (CM) were recorded before surgery, at 6 months and 12 months after surgery. Magnetic resonance imaging (MRI) was performed preoperatively, the day after surgery, and at 6 months. Results: The reconstruction reduced superior translation of the humeral head and subacromial pressure compared with the rotator cuff-deficient condition. No significant differences were observed in basic mechanical properties between the tested tendons. ASES scores improved significantly at both 6 and 12 months after surgery, whereas Constant score did not remain statistically significant in the 12-month pairwise comparison after adjustment for multiple comparisons. No significant differences were observed in shoulder joint range of motion. MRI showed 6/9 (67%) patients had reduced thickness of the implanted peroneus longus tendon (PLT) graft at 6 months postoperatively, while the PLT grafts of the other patients remained intact. Conclusion: SCR with AT may help restore superior glenohumeral stability under controlled biomechanical conditions and shows promising preliminary clinical results in patients with IRCTs.