Retrieval analysis of new-generation yttria-stabilized zirconia femoral heads after total hip arthroplasty.

Zirconia femoral heads were introduced for total hip arthroplasty (THA) with the expectation of lower polyethylene (PE) wear and better clinical results. Because several studies reported poor survivorship of yttria-stabilized zirconia-PE THA, we investigated a new-generation yttria-stabilized zirconia head (diameter, 26 mm) manufactured by NGK Spark Plug. We retrieved six zirconia heads at revision THA after they had been in place for a mean of 8.6 years and measured their surface roughness and mean monoclinic content. Although their mean monoclinic content was higher than that of the unused head, surface roughness in the implanted heads was as low as that of the unused head, indicating that wear reduction may be possible with the selection of a suitable zirconia femoral head.