Does vitamin E highly-crosslinked polyethylene convey an advantage in primary total hip replacement? A systematic review and meta-analysis

Abstract

<jats:sec><jats:title>Background:</jats:title><jats:p> Vitamin E highly cross-linked polyethylene (HXLPE) was developed to reduce wear in total hip replacement (THR). This formal systematic review and meta-analysis aimed to provide independent synthesis of wear characteristics of Vitamin E treated HXLPE compared to HXPLE/UHMWPE. Secondary outcome measures were differences in revision rates and functional scores. </jats:p></jats:sec><jats:sec><jats:title>Methods:</jats:title><jats:p> We performed a formal systematic review as per PRISMA guidelines; literature searches were conducted on 14 November 2017 (MEDLINE, Embase on Ovid, and the Cochrane Library). We included randomised controlled trials, analyses of joint registries, and case-controlled studies of primary THR comparing cups with a vitamin E HXLPE bearing with bearing surfaces made from other types of polyethylene. Initial screening was performed by 2 independent assessors; disagreement resolved in discussion with a third reviewer. Studies were evaluated using the Cochrane risk of bias tool. Data extraction permitted meta-analysis. </jats:p></jats:sec><jats:sec><jats:title>Results:</jats:title><jats:p> 372 studies were identified on initial screening, 5 studies met the eligibility criteria. There was no significant heterogeneity between studies. There was variable risk of bias. At a mean of 35 (range 20–60) months, Vitamin E HXLPE had significant advantages over highly cross-linked polyethylene with regards total femoral head penetration ( p = 0.004). Given the RSA measurement errors this may not be clinically significant. There were neither significant differences in revision rates nor Harris Hip Scores ( p = 0.06). </jats:p></jats:sec><jats:sec><jats:title>Conclusion:</jats:title><jats:p> At a minimum of 3 years follow-up there was reduced total femoral head penetration for vitamin E HXLPE over HXLPE. This bearing surface does not, as yet, have clinically significant advantages in terms of revision rates or patient function over HXLPE. </jats:p></jats:sec>

The effect of structural parameters of total hip arthroplasty on polyethylene liner wear behavior: A theoretical model analysis

“…Various cross‐linked polyethylene materials have been applied in THAs that greatly enhanced the wear resistance of the polyethylene liner but with lower mechanical strengths compared to conventional polyethylene liner materials . Our data indicate that for a fixed cup size or outer polyethylene liner diameter, the relationship between the contact area and stress is nonlinear, as depicted in Figure A,B.…”

“…Although recent studies on highly cross‐linked polyethylene liners showed reduced liner wear and therefore improved implant longevity, whether or how the wear rate depends on structural parameters still remains not to be fully understood. Clinical studies have reported the effect of metal head sizes on polyethylene liner wear using liner retrievals from patients and reported that increased femoral head size was associated with increased volumetric wear .…”

Does Activity Level After Primary Total Hip Arthroplasty Affect Aseptic Survival?

“…The general concern with higher activity level after THA is polyethylene wear. As noted previously, however, polyethylene durability has improved significantly over the past few decades [ [31] , [32] , [33] ]. In a registry analysis, highly crosslinked polyethylene had a 16-year cumulative revision rate of 6.2%, whereas conventional polyethylene had a revision rate of 11.7% [ 3 ].…”

“…The process of crosslinking produces free radicals that can be trapped within the polyethylene [ 34 ]. Antioxidant additives, such as vitamin E, have been added to polyethylene manufacturing to neutralize free radicals and improve polyethylene wear [31] , [32] , [34] , [35] . The polyethylene evaluated in this study is highly crosslinked and vitamin E infused.…”

Recent update on crosslinked polyethylene in total hip arthroplasty

“…Extended reviews have been published about XLPE including vitamin E or other antioxidants [16,17], but to date, main data are collected from ex vivo experiments or clinical studies with less than 5-year follow-up. At this short term, vitamin E poly has not proved any clinically significant advantage in terms of patient function, wear or revision rate as compared to first generation of XLPE.…”