Abstract
Introduction
The optimal bearing for hip arthroplasty is still a matter of debate. in younger and more active patients ceramic-on-polyethylene (CoP) bearings are frequently chosen over metal-on-polyethylene (MoP) bearings to reduce wear and increase biocompatibility. However, the fracture risk of ceramic heads is higher than that of metal heads. This can cause serious issue, as ceramic fractures pose a serious complication often necessitating major revision surgery – a complication more frequently seen in ceramic-on-ceramic bearings. To date, there are no long-term data (> 20 years of follow-up) reporting fracture rates of the ceramic femoral heads in CoP bearings.
Patients and Methods
We retrospectively evaluated the clinical and radiographic results of 348 cementless THAs treated with 2nd generation Biolox® Al2O3 Ceramic-on-Polyethylene (CoP) bearings, which had been consecutively implanted between January 1985 and December 1989. At implantation the mean patient age was 57 years. The cohort was subsequently followed for a minimum of 20 years. At the final follow-up 111 patients had died, and 5 were lost to follow-up (Fig. 1). A Kaplan-Meier survivorship analysis was used to estimate the cumulative incidence of ceramic head fractures over the long-term.
Results
(Figs. 2, 3):
After 22-years the cumulative incidence of ceramic head fracture was estimated at 0.3% (95%-CI, 0–2.4%; 38 hips at risk). No impending failures could be noted on radiographic analysis at final follow-up.
Discussion
The fracture rate of second-generation ceramic heads using a CoP articulation remains very low into the third decade after cementless THA; ceramic heads appear to be a safe alternative to metal femoral heads.
Summary
This study evaluates the long-term (20–25 year) survivorship of cement on polyethylene bearings in uncemented THA.
