What is the Long-term Economic Societal Effect of Periprosthetic Infections After THA? A Markov Analysis

Background Current estimates for the direct costs of a single episode of care for periprosthetic joint infection (PJI) after THA are approximately USD 100,000. These estimates do not account for the costs of failed treatments and do not include indirect costs such as lost wages. Questions/purposes The goal of this study was to estimate the long-term economic effect to society (direct and indirect costs) of a PJI after THA treated with contemporary standards of care in a hypothetical patient of working age (three scenarios, age 55, 60, and 65 years). Methods We created a state-transition Markov model with health states defined by surgical treatment options including irrigation and debridement with modular exchange, single-stage revision, and two-stage revision. Reoperation rates attributable to septic and aseptic failure modes and indirect and direct costs were calculated estimates garnered via multiple systematic reviews of peer-reviewed orthopaedic and infectious disease journals and Medicare reimbursement data. We conducted an analysis over a hypothetical patient's lifetime from the societal perspective with costs discounted by 3% annually. We conducted sensitivity analysis to delineate the effects of uncertainty attributable to input variables. Results The model found a base case cost of USD 390,806 per 65-year-old patient with an infected THA. One-way sensitivity analysis gives a range of USD 389,307 (65-year-old with a 3% reinfection rate) and USD 474,004 (55-year-old with a 12% reinfection rate). Indirect costs such as lost wages make up a considerable portion of the costs and increase considerably as age at the time of infection decreases. Conclusions The results of this study show that the overall treatment of a periprosthetic infection after a THA is markedly more expensive to society than previously estimated when accounting for the considerable failure rates of current treatment options and including indirect costs. These overall costs, combined with a large projected increase in THAs and a steady state of septic failures, should be taken into account when considering the total cost of THA. Further research is needed to adequately compare the clinical and economic effectiveness of alternative treatment pathways.