Does cross-linked polyethylene decrease the revision rate of total hip arthroplasty compared with conventional polyethylene? A meta-analysis

Background: Although cross-linked polyethylene is resistant to wear in comparison to conventional polyethylene, it remains unknown whether it can decrease the wear-related revision rate of total hip arthroplasty. Objectives: To determine whether cross-linked polyethylene decreases the wear-related revision rate of total hip arthroplasty compared with conventional polyethylene. Data sources: Electronic databases, including PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials, were queried from inception to July 6, 2013. Study selection: Randomized controlled trials (RCTs) comparing cross-linked polyethylene with conventional polyethylene were included. In addition, the standard 28-mm femoral head was used, and follow-up was performed for a minimum of 5 years. The primary outcome assessed was wear-related revision. The secondary outcome measures evaluated were the incidence of osteolysis, the linear wear rate, and the linear head penetration. Data synthesis: The Cochrane Collaboration's tool for assessing the risk of bias was used for quality assessment. Data from eligible studies were pooled using a random effects model. Results: Eight studies involving 735 patients were included in this study. Meta-analysis showed there was no significant difference between cross-linked and conventional polyethylene group in terms of osteolysis or wear-related revision. The pooled mean differences were significantly less for the linear wear rate and linear head penetration for cross-linked polyethylene than for conventional polyethylene. Limitations: The studies differed with respect to the cross-linked liner brands, manufacturing processes, and radiological evaluation methods. Moreover, the follow-up periods of the RCTs were not long enough. Conclusions: The current limited evidence suggests that cross-linked polyethylene significantly reduced the radiological wear compared with conventional polyethylene at midterm follow-up periods. However, there is no evidence that cross-linked polyethylene had an advantage over conventional polyethylene in terms of reducing osteolysis or wear-related revision. Nevertheless, future long-term RCTs on this topic are needed. Key findings: Cross-linked polyethylene significantly reduced radiological wear but not osteolysis or wear-related revision in comparison to conventional polyethylene at midterm follow-up periods. (C) 2014 Published by Elsevier Masson SAS.