Bundled Payments for Elective Primary Total Knee Arthroplasty: An Analysis of Medicare Administrative Data.

Bundled payments have been proposed as a mechanism for restraining health care spending for total knee arthroplasty (TKA), but empirical data are limited. We used Medicare data to examine variation in payments for TKA during a window extending 30 days before to 90 days after TKA for 167 186 patients who underwent elective primary TKA in 2009. Mean Medicare payment was US$23 656. We found that 2.5% of patients incurred payments of >US$50 000 (0.2% >US$100 000). Payments were lower for men and for non-Hispanic whites but higher for patients with greater comorbidity. Episode-of-care payment for primary TKA varies substantially depending upon patient demographics and comorbidity. To the extent that similar patients tend to be clustered within hospitals, bundled payments could inadvertently cause financial harm to certain health systems while rewarding others.