Smith and Nephew – Oxinium


Alternate Bearing Surface Total Hip Replacement Study (Oxinium study)

The hip joint is a ball and socket joint. This is a research study evaluating whether different types of material cause hip replacements to wear out at different rates.

Status: Follow up at 5 and 7 years completed. Extended follow-up at 10 years in set-up at Royal Bournemouth Hospital.

Study Design: Participants undergoing THR were randomised to

  • Group A CoCr femoral head and highly cross-linked polyethylene (XLPE) liner
  • Oxidised zirconium (OxZi) femoral head and XLPE liner
  • OxZi femoral head and ultra-high molecular weight polyethylene (UHMWPE) liner

Primary Objective:

  • To examine linear and volumetric radiographic wear in alternative types of total hip replacement (THR) interfaces.

Secondary Objectives:

  • To compare outcomes of THR using health related quality of life (HRQL) measures, radiographic parameters, and complication rates.
  • To evaluate the frequency and predictors of complications following alternative types of THR interfaces.

Follow-up at five years demonstrated that OzZi heads are safe and do not produce high wear rates, with complications and functional scores comparable to those with CoCr heads. However, there is no significant difference between the wear profiles of either material; the choice of acetabular polyethylene liner is more significant than the choice of femoral head bearing although there is a slight trend to lower wear from OxZi. These results indicate that longer follow-up is required to determine if these trends continue and lead to an improved clinical profile and implant lifespan. The study has therefore been extended from five years follow-up to ten years follow up with a mid-review at seven years.

Link to related publication:

Jassim SS, Patel S, Wardle N, Tahmassebi J, Middleton R, Shardlow DL, Stephen A, Hutchinson J, Haddad FS. Five-year comparison of wear using oxidised zirconium and cobalt-chrome femoral heads in total hip arthroplasty. A multi-centre randomised controlled trial. Bone Joint J 2015: 97-B:883-9.