Extensive metallosis following reverse shoulder arthroplasty managed with custom glenoid reconstruction: A case report

Background Metallosis is a rare but serious complication following reverse shoulder arthroplasty (RSA) that can lead to progressive bone loss and implant failure. Although revision strategies have been described planned two-stage revision with custom implants has not previously been reported. Case presentation A 55-year-old female presented with pain and dysfunction following RSA. Examination demonstrated severe motion limitation, while imaging revealed loosening and progressive bone loss. Intraoperatively, we identified extensive metallosis with micromotion at the modular humeral junction, and a large glenoid defect. The initial glenoid baseplate was also positioned relatively high, resulting in impingement and subsequent scapular notching, which may have contributed to the metallosis. Owing to extensive metallosis, severe osteolysis, poor bone stock, and uncertain infection status, a staged revision was performed. An antibiotic spacer was placed and glenoid was bone grafted. Eventually definitive reconstruction was performed using a custom glenoid baseplate and humeral component because standard revision implants could not achieve stable fixation. At 1 year, the patient had improved shoulder function with forward elevation of 130° and was able to perform activities of daily living. Conclusion Catastrophic metallosis secondary to modular junction failure may require staged revision and patient-specific reconstruction when extensive bone loss precludes standard revision implants.