Patient-Specific BIO-RSA for the Treatment of Glenoid Dysplasia (Type-C) Osteoarthritis.

Abstract

To report the mid- to long-term clinical and radiologic outcomes of reverse shoulder arthroplasty with a patient-specific (P-S) structural humeral head autograft (BIO-RSA technique) for the treatment of glenoid dysplasia (Walch type-C) osteoarthritis (OA). This is a retrospective single-center case series of 45 shoulders (37 patients; mean age 76 ± 9 years) with type-C glenoid osteoarthritis (retroversion > 25°) treated using a patient-specific BIO-RSA technique between 2012 and 2022. The cancellous bone graft was harvested from the proximal humerus using a bell saw. A wedge-shaped bone graft (12 to 25 mm) was crafted based on preoperative 3D planning (Blueprint - Tornier) and fixed to the native glenoid using a long (≥25 mm) central baseplate (Tornier Aequalis Reversed II)-either pegged (35 cases) or screwed (10 cases)-along with four peripheral screws. At least 10 mm of the central peg or screw was anchored in the native glenoid. Outcome measures included prosthesis survival, functional and subjective results, bone graft healing, and correction of glenoid retroversion and inclination. The mean follow-up was 6.5 years (range, 2-14 years). At the final follow-up, no reoperations or revisions were required, and no glenoid loosening or complications were observed. The mean retroversion correction was 30° ± 10° (from 37° ± 8° to 7° ± 7°), and the mean RSA angle improved from 13° ± 11° to 0° ± 5° (p < 0.001). CT scan evaluation demonstrated complete bone graft healing in 95% (43/45) of shoulders; partial graft lysis was observed in two cases. Graft size (>20 mm) did not influence healing. Incomplete retroversion correction (>10°) did not significantly impact functional outcomes, and the use of patient-specific guides (27% of cases) was not associated with improved correction. Constant-Murley scores and SSV improved from 40 ± 10 to 80 ± 12, and from 38% ± 13 to 91% ± 9, respectively (p < 0.001). All patients reported being satisfied or very satisfied with the procedure. Our data demonstrates that P-S BIO-RSA is a safe, effective, and durable technique for reconstructing severe posterior erosion seen in type-C glenoid OA, including cases with severe retroversion (>45°) requiring thick bone grafts (>20-mm). The procedure provides excellent functional and subjective outcome, and the structural humeral autograft predictably heals the native glenoid, even in elderly patients (> 80 years).