Fretting and Corrosion Damage of Retrieved Dual-Mobility Total Hip Arthroplasty Systems.

Background: Dual-mobility (DM) total hip arthroplasty (THA) systems are designed to increase stability while potentially avoiding problems associated with large femoral heads. Complications of these systems are not yet fully understood. This study aims at characterizing in vivo performance of DM hip systems and assessing modes of clinical failure. Methods: Under an institutional review boardeapproved implant retrieval protocol, 18 DM THA systems from 17 patients were included. Implants were graded at the head-neck junction for fretting and corrosion based on the system of Goldberg et al. Components were also macroscopically examined for different damage modes. Demographics and surgical data were collected from medical records, and radiographs were assessed for component positioning. Data were analyzed through Spearman rankorder correlation and Mann-Whitney U-tests, with alpha = 0.05. Results: The average length of implantation was 13.4 months with mild to moderate fretting corrosion damage. Polyethylene (PE) liners exhibited edge deformation, scratching, and pitting damage. Metallic components exhibited burnishing and scratching damage. Summed fretting and corrosion scores were strongly correlated (rho = 0.967, P <.0001). Summed corrosion score was moderately correlated with presence of embedding on the PE liner (rho = 0.690, P =.017). PE liner abrasion and edge deformation of the femoral stem taper were moderately positively correlated (rho = 0.690, P =.017). Fretting and corrosion damage were not significantly correlated with patient demographics or radiographic positioning of implants. There were no differences in scores between modular and monoblock designs. Conclusion: These findings demonstrate that dual-mobility THA systems may be susceptible to the same fretting and corrosion damage observed in traditional modular THA systems. Future studies are needed to confirm these results and clinical significance. (C) 2019 Elsevier Inc. All rights reserved.