Cost analysis of staged versus simultaneous bilateral total knee and hip arthroplasty using a propensity score matching

Background Total joint arthroplasty (TJA), including total knee arthroplasty (TKA) and total hip arthroplasty (THA), is required for many patients. This study aimed to evaluate the medical costs, length of stay (LOS), blood transfusion and in-hospital complications in patients undergoing simultaneous and staged TJA.Methods All patients who underwent primary bilateral TJA from 2013 to 2018 in our institute were included. The propensity score matching analysis was performed between simultaneous and staged TJA patients. The difference in medical costs, LOS, blood transfusion and in-hospital complications was compared between simultaneous and staged groups.Results Except for materials fees and general therapy fees, medical costs (bed fees, general therapy fees, nursing care fees, check-up and laboratory test fees, surgical fees and drug fees) were significantly lower in the simultaneous TKA, THA and TJA group. The total average medical costs in simultaneous and staged TKA groups were $15 385 and $16 729 (p<0.001), respectively; THA groups were $14 503 and $16 142 (p=0.016), respectively; TJA groups were $15 389 and $16 830 (p<0.001), respectively. The highest and lowest costs were materials fees and nursing care fees. No significant differences were found for five common comorbidities and postoperative complications between the two subgroups. The simultaneous groups had a shorter LOS and the differences from the staged group for TKA, THA and the TJA group were 8, 6 and 8 days, respectively. The incidence of blood transfusion is higher for simultaneous groups and the difference from the staged group for TKA, THA and TJA is 32.69%, 18% and 29.3%, respectively.Conclusions Our results indicate that simultaneous TKA and THA with a shorter LOS would cost fewer (costs incurred during hospitalisation) than staged TKA and THA. Complication rates were not affected by the choice for staged or simultaneous arthroplasty, but the incidence of blood transfusion was higher in the simultaneous groups