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Trunnion Corrosion in Metal-on-Polyethylene Total Hip Arthroplasty: A Case Series

Introduction: Modular total hip arthroplasty implants can help the operating surgeon reproduce the optimum limb length and offset; however, the modularity can lead to fretting and corrosion with associated metal-related problems. Although metal-on-metal bearings are often reported to have problems, recent case reports suggest that the problems can occur with any articulation, usually as a result of problems at the head/neck junction. Methods: We retrospectively reviewed three cases of a specific implant combination with nontraumatic trunnion failure, with two cases presenting as acute complete dissociation of the femoral head from the neck. Results: All three cases had failure of the Accolade TMZF plus stem and trunnion (Stryker) that progressed rapidly from the onset of symptoms. The most likely contributing factors to failure were large femoral head size, high horizontal offset, a low angled neck, and a &bgr; titanium alloy taper with a cobalt-chromium head. Conclusion: We recommend regular follow-up of all patients with Accolade TMZF stems, and patients should be advised to seek immediate medical attention if they have any new mechanical symptoms in a metal-on-polyethylene total hip arthroplasty. Providers should specifically look for any alteration of alignment between the femoral head and neck in follow-up radiographs.