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Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_3 | Pages 82 - 82
1 Jan 2016
Nebergall A Greene M Sillesen N Rubash HE Kwon Y Malchau H
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Introduction

Osteolysis caused by wear of the ultrahigh molecular weight polyethylene (UHMWPE) often leads to failure. Cross-linking improves wear, but also produces residual free radicals that decrease oxidative stability. In vitro studies have shown that the anti-oxidative properties of vitamin E UHMWPE stabilize free radicals while retaining the physical and chemical properties of UHMWPE. The porous surface of the Regenerex™ shell was developed for improved bone in-growth fixation. The increased porosity of the Regenerex™ shell promotes early bony in-growth with the goal of greater long-term stability. The purpose of this study was to evaluate vitamin E infused polyethylene (VEPE) wear and stability of acetabular and femoral components using RSA.

Methods

58 patients (64 observed hips), all with osteoarthritis, gave informed consent to participate in a 5 year RSA study. Each patient received a VEPE liner, a Regenerex™ acetabular shell, and an uncemented stem with either a 32mm or 36 mm cobalt chrome femoral head. Tantalum beads were inserted into the VEPE, the pelvic and the femoral bone to measure head penetration into the polyethylene, and shell and stem stability over time, using RSA. RSA radiographs were scheduled immediately postoperatively (up to 6 weeks) and 6 months, 1, 2, 3, and 5 years after surgery. The Wilcoxon signed-ranks nonparametric test was used to determine if changes in penetration or migration were significant over time at p≤0.05.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 255 - 255
1 Jul 2014
Bichara D Malchau E Sillesen N Cakmak S Muratoglu O
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Summary Statement

Vitamin E-UHMWPE particles have a reduced osteolysis potential in vivo when compared to virgin, highly cross-linked UHMWPE in a murine calvarial bone model.

Introduction

Ultra high-molecular weight polyethylene (UHMWPE) particle-induced osteolysis is one of the major causes of arthroplasty revisions. The lack of particle clearance from the joint inevitably leads to the upregulation of the inflammatory cascade, resulting in bone resorption and implant loosening. Recent in vitro findings (Bladed CL et al. ORS 2011 and J Biomed Mater Res B Appl Biomater, 2012) have suggested that UHMWPE wear particles containing vitamin-E (VE) may have reduced functional biologic activity and decreased potential to cause osteolysis. This is of significant importance since VE-stabilised cross-linked UHMWPEs were recently introduced for clinical use, and there is no in vivo data determining the effects of wear debris from this new generation of implants. In this study we hypothesised that particles from VE-stabilised, radiation cross-linked UHMWPE (VE-UHMWPE) would cause reduced levels of osteolysis in a murine calvarial bone model when compared to virgin gamma irradiated cross-linked UHMWPE.