Economic benefit to society at large of total knee arthroplasty in younger patients: a Markov analysis.

Background: To our knowledge, the economic implications of total knee arthroplasty to society at large have not been assessed with specific consideration of the young working population with osteoarthritis of the knee. The goal of the present study was to use a Markov analysis to estimate the overall average cost to society--in terms of medical expenses and lost wages--of delaying early total knee arthroplasty in favor of nonoperative treatment for end-stage knee osteoarthritis in a hypothetical fifty-year-old patient.

Methods: A Markov state-transition decision model was constructed to compare the overall average cost over thirty years of total knee arthroplasty with the average thirty-year cost of nonoperative treatment for a fifty-year-old patient with end-stage osteoarthritis. Earned income, lost wages, and direct medical costs related to nonoperative treatment and to total knee arthroplasty, including revisions and complications, were considered. A sensitivity analysis was performed to assess the effect that variation of key model parameters had on the overall outcome of the model.

Results: This Markov model favored early total knee arthroplasty over nonoperative treatment across all plausible values for most input parameters assessed during one-way sensitivity analysis. Total knee arthroplasty was more expensive during the first 3.5 years because of higher initial costs, but over thirty years the cost benefit of total knee arthroplasty was $69,800 (2012 U.S. dollars). Only when lost wages were <17.7 equivalent work days per year for patients treated nonoperatively or when the rate of returning to work after total knee arthroplasty was <81% did the model favor nonoperative treatment.

Conclusions: The results of the current study demonstrated that the total economic cost to society for treatment of severe knee osteoarthritis in a relatively young working person is markedly lower with total knee arthroplasty than it is with nonoperative treatment. The increasing financial restrictions on health-care providers in the U.S. necessitate careful consideration of the economic impact of different treatment options from the societal perspective.

Clinical Relevance: The results of this model illustrate the need to account for the implications of treatment choices, not only at the individual patient level, but also for society at large. When deciding among available treatment options, patients, physicians, payers, and policymakers must consider individual treatment cost and effectiveness but also should account for future potential earnings generated when a treatment may restore a patient's ability to contribute to society.