Component Mix-Match for Anatomic Total Shoulder Arthroplasty Revision: A Case Report

Although mixing and matching components is a common, safe, and well-documented practice in hip revision surgery, our extensive search indicates that it has not been previously reported for shoulder arthroplasty. This case report presents the use of mixed implants in shoulder revision surgery to reduce morbidity and address flaws in the initial implant design. We describe a case of a patient with multiple epiphyseal dysplasia who was treated for osteoarthritis in his left shoulder with an anatomic shoulder replacement in 2014. In 2018, the patient presented with deteriorating function, increasing pain, and radiological signs of glenoid component wear and loosening. A decision was made to proceed with revision shoulder arthroplasty. Given the patient's young age and intact rotator cuff function, the revision was planned as an anatomic construct. The challenge was a well-fixed, fully hydroxyapatite-coated stem and a glenoid metal-backed component with a failing polyethylene locking mechanism. After extensive discussion with the patient, a combined decision was made to retain the well-fixed humeral stem and revise the glenoid side using impaction grafting with allograft, followed by cementing an all-polyethylene glenoid from a different company. The revision surgery was performed uneventfully, resulting in pain relief and improved function beyond the levels achieved in the initial operation. Notably, the original head and the revision glenoid had a curvature radius mismatch, in contrast to the original design's absolute congruence. Recent studies suggest that such a mismatch, within limits, can recreate normal shoulder kinematics and reduce glenoid loosening.