Glenoid Component Migration in Total Shoulder Arthroplasty: A Case Report

Glenoid component migration is a serious complication in total shoulder arthroplasty, causing 32% of failures and 7% of revisions. Detecting polyethylene loosening is challenging due to its radiolucency. We report a case of a 72-year-old woman with shoulder pain three years post-arthroplasty. Initial radiographs were unremarkable, but CT-arthrography revealed a displaced polyethylene spacer, rotated 90°, thus causing a mechanical block. Retrospective analysis of the X-rays showed the absence of the spacer in the expected position. Surgery restored functionality. This case highlights the diagnostic challenges of radiotransparent components with possible migration in unexplained post-arthroplasty shoulder pain. <i>Teaching point:</i> Verify glenoid component positioning in shoulder arthroplasties.