Fifteen-year survival analysis of an oxidised zirconium total knee arthroplasty.

Background: Early studies have found Oxidised Zirconium (OxZr-Nb) total knee arthroplasties to have a low incidence of failure in young, high demand patients. Theoretically this is because they are low friction and hard wearing. However, there are a paucity of studies reporting on the outcome of these implants beyond ten years. The purpose of our study was to present an in-depth 15-year survival analysis of a cemented OxZr-Nb knee arthroplasty.

Methods: Data was collected prospectively and survival analysis undertaken with multiple strict end-points. Complication rates and patient reported outcomes were measured post-operatively.

Results: Six hundred and seventeen knee arthroplasties were analysed. Forty-nine patients required a reoperation for various reasons. Aseptic tibial loosening was the most common cause of failure (32.7%), occurring, on average, 2.8 years after the primary procedure. There was only one oxidised zirconium femoral failure recorded. Cumulative survivorship for reoperation for any reason was 91.52% at 15-years. On average, WOMAC (Western Ontario and McMaster University) score improved by 21.2 points at one-year post-surgery, which is beyond the considered minimum clinically important difference.

Conclusion: This study presents a 15-year survival analysis of a cemented oxidised zirconium knee arthroplasty showing good survivorship over a range of analyses.