Knee replacement survival rates with all- polyethylene or metal-backed tibial components – what do the Registries say?

Background: With increasing numbers of primary total knee arthroplasty and  ongoing economic pressure the use of all-polyethylene tibial components maybe an alternative option to achieve cost savings without an adverse impact on outcomes  Methods: A search of all publically available joint replacement registry data investigated the performance of all-polyethylene tibial components compared to metal backed modular tibial components. Results: All-polyethylene tibial components were used in 0.47% of Australian and 1.2% of England and Wales national register reported knees. 2.6% of Norwegian fixed platform knees were all-polyethylene. Large institutional registers from the United States of America reported usage rates of 4%, 8.3% and 8.9%.  Revision rates for all-polyethylene implants were comparable or better than modular components in all registries. Only one registry had sufficient data on patients aged less than 65 years who report a hazard ratio of 0.26. Conclusion: In patients 65 years and older all polyethylene tibial components have similar rates of revision compared to metal backed. There is insufficient data in younger patients.