A multicenter approach evaluating the impact of vitamin e-blended polyethylene in cementless total hip replacement.

Abstract

Since polyethylene is one of the most frequently used biomaterials as a liner in total hip arthroplasty, strong efforts have been made to improve design and material properties over the last 50 years. Antioxidants seems to be a promising alternative to further increase durability and reduce polyethylene wear in long term. As of yet, only in vitro results are available. While they are promising, there is yet no clinical evidence that the new material shows these advantages in vivo. To answer the question if vitamin-E enhanced ultra-high molecular weight polyethylene (UHMWPE) is able to improve long-term survivorship of cementless total hip arthroplasty we initiated a randomized long-term multicenter trial. Designed as a superiority study, the oxidation index assessed in retrieval analyses of explanted liners was chosen as primary parameter. Radiographic results (wear rate, osteolysis, radiolucency) and functional outcome (Harris Hip Scores, University of California-Los Angeles, Hip Disability and Osteoarthritis Outcome Score, Visual Analogue Scale) will serve as secondary parameters. Patients with the indication for a cementless total hip arthroplasty will be asked to participate in the study and will be randomized to either receive a standard hip replacement with a highly cross-linked UHMWPE-X liner or a highly cross-linked vitamin-E supplemented UHMWPE-XE liner. The follow-up will be 15 years, with evaluation after 5, 10 and 15 years. The controlled randomized study has been designed to determine if Vitamin-E supplemented highly cross-linked polyethylene liners are superior to standard XLPE liners in cementless total hip arthroplasty. While several studies have been started to evaluate the influence of vitamin-E, most of them evaluate wear rates and functional results. The approach used for this multicenter study, to analyze the oxidation status of retrieved implants, should make it possible to directly evaluate the ageing process and development of the implant material itself over a time period of 15 years.