Functional and Radiographic Outcomes of Bone Grafting for Severe Glenoid Defects in Reverse Shoulder Arthroplasty: A Minimum 5-Year Follow-up.

Background: The outcomes of bone grafting for severe glenoid defects in reverse shoulder arthroplasty (RSA) are unpredictable. The purpose of this study was to describe the intermediate-term outcomes of glenoid bone grafting in RSA for severe glenoid defects utilizing a baseplate with a long central post.

Methods: All patients who underwent glenoid bone grafting for severe glenoid defects during RSA from 2008 to 2018, with a minimum of 5-year follow-up, were included. Preoperative, immediate postoperative, and minimum 5-year postoperative American Shoulder and Elbow Surgeons (ASES) scores and visual analog scale (VAS) pain scores and radiographs were obtained and reviewed. Baseplate failure was defined as gross radiographic baseplate cutout or baseplate revision due to implant loosening.

Results: Of the 56 shoulders that underwent bone grafting, 14 were not available because the patients had died and 1 was excluded because of infection, leaving 41 shoulders available for follow-up. There were 4 shoulders in which the patients were lost to follow-up; therefore, the final follow-up rate was 90% (37 of 41) at a mean of 6.8 ± 2.4 years. There were 17 revision procedures and 20 primary procedures performed. Autograft humeral head was utilized in 16 shoulders, and femoral head allograft was utilized in 21 shoulders. Overall, 8 baseplates failed (allograft, 7 [33.3% failure] of 21; autograft, 1 [6.3% failure] of 16; p = 0.104). Revision surgery (7 [41.2%] of 17) was associated with a higher rate of baseplate failure (p = 0.014) than primary procedures (1 [5%] of 20). The mean time to baseplate failure was 2.1 ± 1.5 years, with 2 cases having failure after 4 years postoperatively. Male sex and a lower Charlson Comorbidity Index were associated with baseplate failure (all p < 0.05). The 5-year overall baseplate survivorship was 78.4%.

Conclusions: Glenoid bone grafting with RSA for severe glenoid defects had an overall baseplate survivorship rate of 78.4% at the intermediate-term follow-up. Primary RSA with autografting for severe defects yielded survivorship of 95%, whereas revision RSA with allograft reconstruction had poorer survivorship (58.8%). Although primary RSA with autograft reconstruction resulted in a high success rate, revision RSA with allograft reconstruction using a central-post baseplate had an elevated baseplate failure rate and alternative surgical solutions for revision RSA should be considered.

Level Of Evidence: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.