Introduction: We present a case of metallosis following a reverse total shoulder arthroplasty. We are not aware of any cases described in literature of metallosis following reverse total shoulder arthroplasty with well-fixed implants. To date, there have been four cases described in literature that have found metallosis following shoulder replacement surgery: three following hemiarthroplasty and one following total shoulder arthroplasty.
Case Report: Our patient dislocated seven months postoperatively, and with concern of further instability as noted on examination, the patient was taken to the operating room for glenosphere and liner exchange. During surgery, severe metallic staining was discovered in the joint as well as significant inferomedial wear to the polyethylene insert. This was likely due to instability as a result of inadequate tension on the deltoid muscle, inadequate liner size, early hypermobility, downward tilt of the glenoid, and failure to lateralize the component sufficiently. It is our hypothesis that the glenoid component articulated with the metal humeral neck due to asymmetric polyethylene wear of the humeral cup. This likely led to metal-on-metal wear and allowed the release of metal ions into the local environment.
Conclusion: Future consideration must be given to the size and angle of the humeral and glenoid components in reverse total shoulder arthroplasties. It is our hope that our case emphasizes the importance of proper prosthetic placement and establishes a higher level of suspicion for metallosis as a complication for reverse total shoulder arthroplasties.