2017 ISAKOS Biennial Congress ePoster #1204

 

Twelve Year Outcomes of an Oxinium Total Knee Arthroplasty Compared to the Same Design In Cobalt Chrome: An Analysis of 17,577 Prostheses from the Australian Orthopaedic Association National Joint Replacement Registry.

Christopher J. Vertullo, MBBS, PhD, FRACS(Orth), Gold Coast, QLD AUSTRALIA
Peter L. Lewis, MBBS, FRACS(Orth), FAOrthA, Adelaide, SA AUSTRALIA
Stephen E. Graves, MBBS, DPhil, FRACS, FAOrthA, Adelaide, SA AUSTRALIA
Lan Kelly, PhD, Adelaide AUSTRALIA
Michelle Lorimer, BSc(Hons), Adelaide, SA AUSTRALIA
Peter T. Myers, MBBS, FRACS, FAOrthA, Brisbane, Queensland AUSTRALIA

Knee Research Australia & Australian Orthopaedic Association National Joint Replacement Registry, Gold Coast, QLD, AUSTRALIA

FDA Status Cleared

Summary

Oxinium femoral components did not reduce revision rates in TKR due to all causes, loosening/lysis or when infection as a cause of revision was removed, compared to the same Co-Cr femoral component, across all age groups including patients who were under 55 years of age.

Abstract

Background

Oxidized Zirconium (Oxinium) was introduced as an alternative bearing surface to Cobalt Chrome (Co-Cr) in an attempt to reduce polyethylene wear and decrease Total Knee Arthroplasty (TKA) aseptic mechanical failure. While non-comparative reports have been described as promising, we are aware of no short or long-term clinical studies showing the superiority of Oxinium on polyethylene as a bearing surface. Using data from a comprehensive national joint replacement registry we investigated the long-term outcomes of Oxinium compared to the same design Co-Cr Cruciate Retaining (CR) TKA.

Methods

Cumulative Percent Revision (CPR) and Hazard Ratio (HR) for revision risk was estimated for the cemented Genesis II Oxinium and Co-Cr CR TKA performed in Australia from 1 September 1999 to 31 December 2013. In addition, the revision diagnoses, the effect of age and patella resurfacing were examined.

Results

17,577 cemented Genesis II CR TKA using non cross-linked polyethylene were performed, 11,608 with Co-Cr femoral components and 5,969 with Oxinium femoral components. No difference in the HR for revision risk was found between the Oxinium and Co-Cr cohorts for any age category for all causes of revision (HR = 0.92 (95%: CI 0.92, 1.29), p = 0.329), loosening/lysis or all non-infective causes, except for loosening/lysis in the >75 years old group (p=0.033). In these patients, TKA with Oxinium femurs had a higher rate of revision. Younger patients preferentially received Oxinium femoral components. Patella resurfacing, and non-resurfacing, did not affect the revision risk. At 12 years the CPR of the Co-Cr Genesis II was 4.8 % (95%: CI 4.2, 5.4) compared to a CPR of 7.7 % (95%: CI 6.2, 9.5) for Oxinium Genesis II.

Conclusions

In this same prosthesis-design cohort study, Oxinium femoral components did not reduce revision rates due to all causes, loosening/lysis or when infection as a cause of revision was removed, compared to the same Co-Cr femoral component, across all age groups including patients who were under 55 years of age.

Level of Evidence: II