Background: The purpose of this study was to analyze whether the cost for ceramic-on-polyethylene (C-PE) and ceramic-on-ceramic (COC) bearings used in primary total hip arthroplasty was changing over time, and if the cost differential between ceramic bearings and metal-on-polyethylene (M-PE) bearings was approaching the previously published tipping point for cost-effectiveness of $325. Methods: A total of 245,077 elderly Medicare patients (65+) who underwent primary THA between 2010 and 2015 were identified from the United States Medicare 100% national administrative hospital claims database. The inpatient hospital cost, calculated using cost-to-charge ratios, and hospital payment were analyzed. The differential cost of C-PE and COC bearings, compared to metal-on-polyethylene (M-PE), were evaluated using parametric and nonparametric models. Results: After adjustment for patient and clinical factors, and the year of surgery, the mean hospital cost and payments for primary THA with a C-PE or COC was within ±1% of the cost for primary THA with M-PE bearings (p<0.001). From the nonparametric analysis, the median hospital cost was $318-360 more for C-PE and COC than M-PE. The differential in median Medicare payment for THA with ceramic bearings compared to M-PE was <$100. Cost differentials were found to decrease significantly over time (p < 0.001). Conclusion: Patient and clinical factors had a far greater impact on the cost of inpatient THA surgery than bearing selection. Because we found that costs and cost differentials for ceramic bearings were decreasing over time, and approaching the tipping point, it is likely that the cost-effectiveness thresholds relative to M-PE are likewise changing over time and should be revisited in light of the present study.
