Health State Utilities and Cost-Effectiveness Economic Evaluation for Treatment of a Symptomatic Accessory Navicular

Background: Treatment strategies for a symptomatic accessory navicular include both operative and nonoperative approaches. The primary aim of this study is to define health utility values for 7 health states experienced by those with a symptomatic accessory navicular who undergo operative and/or nonoperative treatment. Secondarily, the study incorporates the health utility values with treatment costs, probabilities of various outcomes, and duration of health states into a cost-effectiveness model comparing the nonoperative treatment protocol at our institution vs surgical excision. Methods: Institutional review board approval was obtained to call parents of patients 10-20 years old at the time of interview who were evaluated for a symptomatic accessory navicular from February 1, 2016, to March 2, 2023, at a single institution by one of 4 pediatric orthopaedic surgeons. Participants were asked to rate 7 health states from 0 to 100, with 0 representing death (if 18 years or older) or the worst health imaginable (if under 18 years) and 100 representing perfect health. Using published values for the probabilities of various treatment outcomes, time spent in various health states, and Medicare costs from the perspective of the payor and society, a decision analysis was constructed. Results: Health utility values for 7 health states were obtained. Operative treatment was preferred to nonoperative treatment in the base case model. Surgery was more expensive ($16 825) than nonoperative treatment ($7486). Using a willingness-to-pay threshold of <$50 000 per quality-adjusted life year (QALY), surgery was cost-effective compared to nonoperative treatment with an incremental cost-effectiveness ratio of $20 303/QALY. Sensitivity analysis revealed that the only variable that indicated a preference for nonoperative treatment is a 71% likelihood of nonoperative treatment resolving the condition. Conclusion: Unless a physician suspects at least a 71% chance of a symptomatic accessory navicular resolving without operative treatment, surgical excision is recommended from a cost-effectiveness perspective.