Long-term durability of alumina ceramic heads in THA

Background

The optimal type of bearing for hip arthroplasty remains a matter of debate. Ceramic-on-polyethylene (CoP) bearings are frequently used in younger and more active patients to reduce wear and increase biocompatibility compared to Metal-on-Polyethylene (MoP) bearings. However, in comparison to metal heads, the fracture risk of ceramic heads is higher. In addition, ceramic head fractures pose a serious complication which often necessitates major revision surgery. To date, there are no long-term data (>20 years of follow-up) reporting fracture rates of the ceramic femoral heads in CoP bearings. The purpose of this research was to investigate long-term CoP fracture rate.

Methods

We evaluated the clinical and radiographic results of 348 cementless THAs treated with 2^nd generation Biolox® Al₂O₃ Ceramic-on-Polyethylene (CoP) bearings consecutively implanted between January 1985 and December 1989. The mean age at implantation was 57 years. The patients were followed for a minimum of 20 years. At the final 111 had died, and 5 were lost to follow-up. The cumulative incidence of ceramic head fractures in the long-term was estimated using a competing risk analysis.

Results

The cumulative incidence of ceramic head fracture after 22-years was estimated with a competing risk analysis at 0.29 % after 22-years (SE = 2.09 %; 95 % – CI: 0.03-1.5 %). The radiographic analysis revealed no impending failures at final follow-up.

Discussion/Conclusion

The fracture rate of second-generation ceramic heads using a CoP articulation remains very low into the third decade after cementless THA.