The effect of patient-reported metal allergies on the outcomes of shoulder arthroplasty

Background: Although literature exists regarding hip and knee arthroplasty outcomes in patients with skin allergy to metals, there is minimal information about skin allergy implications on shoulder arthroplasty outcomes. The purpose of this study was to determine the results, complications, and failure rate among patients with a self-reported metal allergy undergoing shoulder arthroplasty. Methods: Fifty-two shoulder arthroplasties were performed at our Institution in 43 patients with self-reported metal allergies. Forty primary and 12 revision shoulder arthroplasties were performed using anatomic (30) and reverse (22) components. Retrospective chart review was performed to determine metal allergy history, implant composition, pain, motion, and complications. Radiographs were reviewed to determine mechanical failure rates. Average follow-up time was 65 months. Results: Allergies reported included nickel (37), cobalt chrome (4), copper (2), zinc (1), titanium (1), gold (1), and nonspecific metal allergy (8); 8 patients reported multiple metal allergies. All components implanted in patients with nickel allergies contained nickel. At most recent follow-up, pain was rated as none or mild in 88% of shoulders. Active elevation improved from 80° to 141° and external rotation from 24° to 52°. Two revisions were performed for glenoid loosening (3.8%); both were revision cases with substantial glenoid bone loss. One patient with mild pain had a radiographically loose glenoid component 12 years after anatomic shoulder arthroplasty. Conclusion: Results from this study suggest that shoulder arthroplasty in patients with self-reported metal allergy provides satisfactory pain relief and improved range of motion with low revision rates.