JSES International · Published 2026-04-10 · DOI 10.1016/j.jseint.2026.101709
Background: Glenoid loosening is a well-documented failure mechanism in anatomic shoulder arthroplasty. Implant manufacturers have developed innovative designs to address these issues, with hybrid glenoid components emerging as a potential solution. This study investigates the Exactech Equinoxe glenoid (Exactech Inc., Gainesville, FL, USA), a hybrid component that has shown higher midterm revision rates in national registry data. Methods: We conducted an investigation of failed Equinoxe Cage Glenoid implants revised between November 2022 and July 2025 and analyzed at a tertiary arthroplasty retrieval center. Clinical data, radiographs, and intraoperative findings were reviewed. Radiographs were assessed for radiolucency (Lazarus score), implant position, and evidence of fracture or metallic debris. Retrieved components underwent macroscopic inspection and evaluation of wear modes. Polyethylene (PE) oxidation was quantified through white-banding assessment and Fourier Transform Infrared Spectroscopy. Periprosthetic tissues, when available, underwent inductively coupled plasma mass spectrometry to evaluate metal ion presence. Results: Eleven failed hybrid glenoid components were analyzed at a median of 5.8 years after implantation. Radiographic loosening was present in 82% of cases (median Lazarus score 5). All retrieved components demonstrated macroscopic PE wear; 82% showed cracking and delamination. Fourier Transform Infrared Spectroscopy confirmed subsurface oxidation in all tested components. Peripheral peg fixation was limited, with 100% of pegs demonstrating minimal bony ongrowth and 45% showing polishing consistent with micromotion. In contrast, 100% of central metal cages exhibited bony ingrowth. Metal debris or staining was noted in 55% of cases, and tissue samples demonstrated elevated metal ions consistent with cage or peg wear. Conclusion: Failed Equinoxe Cage Glenoid implants demonstrated consistent patterns of PE oxidation and inadequate peripheral peg fixation, contributing to loosening and mechanical failure at the PE–metal interface. These findings provide a potential mechanism for the higher revision rate observed in national registry data and highlight the importance of ongoing postmarket surveillance of new implant designs.
Abstract from DOAJ. Public domain (CC0 1.0).
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