The Effect of Insurance Type on Length of Stay Following Total Knee Arthroplasty

With the expansion of the Affordable Care Act in 2014, there has been a growing interest in how the Medicaid population will affect postoperative outcomes following total knee arthroplasty (TKA). Studies have shown that lower socioeconomic status, non-Caucasian race, women, cardiac and renal disorders, and younger age have been associated with increased lengths of stay (LOS) after TKA. The primary purpose of our study was to compare the total complications and LOS among patients undergoing TKA who have cash, commercial, government, Medicaid, and Medicare insurances.

We queried a national, all-payer administrative claims database from 2016 to 2022 among patients undergoing TKA who had cash (n = 3,923), commercial (n = 966,169), government (n = 25,644), Medicaid (n = 56,184), and Medicare (n = 524,034) insurances. We compared and analyzed various baseline demographics, total complications, and LOS (<1 day, 1 to 2 days, 3 to 4 days, and >4 days), between the insurance types.

Medicaid and Medicaid insurance types had patients who had the most comorbidities at baseline, including a comorbidity index >3 (P < 0.0001), women, alcohol abuse, diabetes, obesity, tobacco use, chronic kidney disease, and congestive heart disease (all P < 0.0001). In accounting for comorbidities, Medicaid was the biggest risk factor for total complications (P < 0.001) as well as increased LOS after TKA at 4 to 6 days, 7 to 9 days, and >9 days (P < 0.0001).

Medicaid insurance is a risk factor for increased total complications and LOS following TKA. Appropriate preoperative and perioperative management of these patients is essential in order to mitigate the risk and burden on the health care system in this population.