Medicare/Medicaid Insurance Status Is Associated With Reduced Lower Bilateral Knee Arthroplasty Utilization and Higher Complication Rates

Abstract

Whether to undergo bilateral total knee arthroplasty (BTKA) depends on patient and surgeon preferences. We used the National Inpatient Sample to compare temporal trends in BTKA utilization and in-hospital complication rates among TKA patients ≥50 with Medicare/Medicaid versus private insurance from 2007 to 2016. We used multivariable logistic regression to assess the association between insurance type and trends in utilization and complication rates adjusting for individual-, hospital-, and community-level covariates, using unilateral TKA (UTKA) for reference. Discharge weights were used for nationwide estimates. About 132,400 (49.5%) Medicare/Medicaid patients and 135,046 (50.5%) privately insured patients underwent BTKA. Among UTKA patients, 62.7% had Medicare/Medicaid, and 37.3% had private insurance. Over the study period, BTKA utilization rate decreased from 7.18% to 5.63% among privately insured patients and from 4.59% to 3.13% among Medicaid/Medicare patients (P trend difference <0.0001). In multivariable analysis, Medicare/Medicaid patients were less likely to receive BTKA than privately insured patients. Although Medicare/Medicaid patients were more likely to develop in-hospital complications after UTKA (adjusted odds ratio, 1.06; 95% confidence interval, 1.002 to 1.12; P = 0.04), this relationship was not statistically significant for BTKAs. In this nationwide sample of TKA patients, BTKA utilization rate was higher in privately insured patients compared with Medicare/Medicaid patients. Furthermore, privately insured patients had lower in-hospital complication rates than Medicare/Medicaid patients.

Figure 1

Healthcare Cost and Utilization Project National Inpatient Sample flowchart. TKA = total knee arthroplasty.

Figure 2

Graph showing the percentage of bilateral total knee arthroplasties (TKAs) among all TKAs by primary insurance.

Figure 3

A, Graph showing unilateral total knee arthroplasty complication rates by primary insurance. B, Graph showing bilateral total knee arthroplasty complication rates by primary insurance.

Figure 4

Graph showing adjusted models demonstrating the relationship of insurance and in-hospital complication rates. Models adjusted for individual demographics (age, race, and primary payer), ecological characteristics (median household income per ZIP code) and hospital characteristics (region, bed size, and location/teaching status). aOR = adjusted odds ratio, CI = confidence interval, TKA = total knee arthroplasty.

Figure 5

Graph showing bilateral total knee arthroplasty (TKA) trends stratified by primary insurance and race.