Outcomes following Humeral Head Autograft Glenoid Reconstruction in Primary Reverse Total Shoulder Arthroplasty.

ABSTRACT

BACKGROUND: Patients with severe glenoid bone loss are at increased risk for poor implant fixation, scapular notching, dislocation, joint kinematic disturbances, and prosthetic failure following reverse total shoulder arthroplasty (rTSA). Glenoid bone grafting has proven useful when performing rTSA in patients with inadequate glenoid bone stock, although the current literature is limited. The purpose of this study is to evaluate clinical outcomes in patients with significant glenoid deformity undergoing primary rTSA with one-stage glenoid reconstruction using a humeral head autograft. METHODS: A database of prospectively enrolled patients was reviewed to identify patients who underwent primary rTSA with humeral head autograft (n=40) between 2008 and 2020 by six high-volume shoulder arthroplasty surgeons with minimum two-year follow-up. Variables studied included demographics, medical comorbidities, range of motion (ROM), Constant score, American Shoulder and Elbow Surgeons (ASES) score, pain score, patient satisfaction, glenoid deformity, revisions and complications. Preoperative glenoid deformity was characterized using glenoid version and beta-angles, measured on computed tomography (CT). Improvement at final follow-up was compared to a matched control group of 120 standard primary rTSA patients. Following the post hoc Bonferroni correction, an adjusted alpha value of 0.004 was used to define statistical significance. RESULTS: Forty patients were included with a mean follow-up of 5.3 (range, 2.0-13.2) years. Patients exhibited a mean preoperative glenoid retroversion and beta-angle of 29° and 80°, respectively. At final follow-up, patients who received a graft exhibited lower mean scores for active external rotation (25° vs. 39°; p = 0.001) in comparison to those who did not receive a graft. No differences were observed in active abduction (p = 0.029), active forward elevation (p = 0.009), active internal rotation (p = 0.147), passive external rotation (p = 0.082), Global Shoulder Function score (p = 0.157), Constant score (p = 0.036), ASES score (p = 0.009), or pain score (p = 0.186) between groups. Seven patients (17.5%) exhibited complications of which the most common being aseptic glenoid loosening (15%). CONCLUSION: This study demonstrates that patients undergoing primary rTSA with autogenous humeral head autograft for severe glenoid deficiency experience postoperative improvements in ROM and functional outcome scores that exceeded the minimal clinically important difference and substantial clinical benefit but inferior to matched controls. This suggests that glenoid reconstruction using a resected humeral head autograft is an effective strategy when conducting primary rTSA in patients with significant glenoid deformity.