Low wear rate at 6-year follow-up of vitamin E-infused cross-linked polyethylene: a randomised trial using 32- and 36-mm heads. Issue 4 (July 2019)

• Record Type: Journal Article
• Authors: Lindalen, Einar; Thoen, Peder S; Nordsletten, Lars; Høvik, Øystein; Röhrl, Stephan M
• Is Part Of: Hip international. Volume 29:Issue 4(2019)
• Page Start: 355
• Page End: 362
• Publication Date: 2019-07
• Subjects: Cross-linked -- hip -- radiosterometric -- RSA -- THA -- vitamin E; Hip joint -- Pathophysiology -- Periodicals; Hip joint -- Diseases -- Periodicals; Hip joint -- Surgery -- Periodicals; 617.581005
• DOI: 10.1177/1120700018798790
• Languages: English
• ISSNs: 1120-7000

Abstract

Background: Free radicals formed in the cross-linking process may over time alter the mechanical properties of highly cross-linked polyethylene. Vitamin E-infused highly cross-linked polyethylene was therefore developed to achieve low wear-rate and good mechanical properties in the long term. Aim: To present 6-year results from the initial randomised controlled trial. Patients and methods: We measured wear and periacetabular bone remodelling in cementless total hip arthroplasty; 32- or 36-mm Biolox Delta heads and vitamin E-infused highly cross-linked polyethylene (E-Poly) were used. Markerless radiosterometric analysis measured the in vivo wear and dual energy x-ray absorptiometry was used to analyse bone remodelling in 40 hips at 6-year follow-up. Results: In the proximal direction the wear for 32- and 36-mm heads was 0.15 mm (95% confidence interval [CI], 0.08–0.21) and 0.06 mm (95% CI, -0.002–0.12), respectively ( p = 0. 015). However, between 3 months and 6 years (excluding the period of "bedding in"), the proximal wear for 32- and 36-mm heads was 0.10 mm (95% CI, 0.05–0.15) and 0.05 mm (95% CI, -0.01–0.11), respectively ( p = 0.12). The annual proximal wear rate for 32- and 36-mm heads from 3 months to 6 years was 0.02 mm and 0.01 mm, respectively. There was no difference in bone remodelling around the cup from baseline to 6 years for the total material and no differences between study groups. Conclusion: Wear of this vitamin E-infused highly cross-linked polyethylene is still low at 6-year follow-up, with no significant difference in wear from 3 months to 6 years between 32- and 36-mm heads.