Adjustable Free Tendon Transplantation For Superior Capsular Reconstruction In Irreparable Giant Rotator Cuff Tears

PURPOSE: This study aimed to evaluate the biomechanical feasibility of superior capsular reconstruction (SCR) with adjustable free tendon transplantation for treating irreparable rotator cuff tears (IRCTs) using cadaveric shoulders. METHODS: Ten fresh-frozen human upper limb specimens were utilized to construct four models: Model A (intact shoulder), Model B (IRCT shoulder), Model C (SCR using a dermal matrix graft), and Model D (SCR with adjustable free tendon transplantation). A custom-designed biomechanical platform was used to test humeral head superior translation and subacromial pressure at 0°, 30°, and 60° of glenohumeral abduction. Statistical analysis was conducted using ANOVA with Tukey’s post hoc tests, with significance set at P < 0.05. RESULTS: Model B exhibited significantly increased humeral head superior translation (0.48 ± 0.05 cm at 0°, 0.34 ± 0.04 cm at 30°, and 0.21 ± 0.02 cm at 60°) and elevated subacromial pressure (1.18 ± 0.08 MPa at 0°, 1.03 ± 0.09 MPa at 30°, and 1.47 ± 0.04 MPa at 60°) compared to Model A (P < 0.01). Models C and D demonstrated significantly reduced superior translation (Model C: 0.30 ± 0.03 cm at 0°, 0.20 ± 0.02 cm at 30°, 0.15 ± 0.03 cm at 60°; Model D: 0.20 ± 0.02 cm at 0°, 0.15 ± 0.02 cm at 30°, 0.12 ± 0.02 cm at 60°; P < 0.01) and decreased subacromial pressure (Model C: 0.90 ± 0.06 MPa at 0°, 0.75 ± 0.04 MPa at 30°, 1.02 ± 0.08 MPa at 60°; Model D: 0.49 ± 0.07 MPa at 0°, 0.67 ± 0.05 MPa at 30°, 0.81 ± 0.05 MPa at 60°; P < 0.01) compared to Model B. Model D exhibited significantly superior biomechanical performance compared to Model C (P < 0.05). CONCLUSIONS: Superior capsular reconstruction with adjustable free tendon transplantation effectively restricts superior humeral head translation and reduces peak subacromial pressure, which demonstrates superior biomechanical efficacy than the conventional SCR techniques.