Study Compares Racial Disparities in Unilateral Versus Bilateral TKA

    Disparities in unilateral total knee arthroplasty (TKA) have been well-documented, with lower utilization and higher complication rates found among African American patients. Less is known, however, about whether these racial variations are seen with same-day bilateral TKA as well.

    That is, until now: In a study presented at ACR Convergence 2020, the annual meeting of the American College of Rheumatology, researchers from Hospital for Special Surgery (HSS) showed that African American patients are less likely to undergo same-day bilateral TKA, but when they do, complication rates are not higher than in white patients.

    Using data from the National Inpatient Sample (NIS) – Healthcare Cost and Utilization Project (HCUP) database, the researchers examined trends in utilization and major in-hospital complication rates of unilateral versus bilateral knee replacement performed between 2007 and 2016 in patients age 50 and older. They assessed racial differences over time, adjusting for age, sex, and comorbidities; hospital variables, including hospital volume, number of beds, region, and teaching status; and community level factors, such as median household income.

    Between 2007 and 2016, 5.5 million unilateral and 276,000 bilateral knee replacements were performed in the US. The percentage of bilateral knee replacements declined from 5.53% in 2007-08 to 4.03% in 2015-16.

    African Americans were found to be much less likely to undergo bilateral TKA than white patients during the years analyzed:

    • 4.68% for African American patients versus 6.08% for white patient in 2007-08
    • 3.28% for African American patients versus 4.19% for white patients in 2015-16

    In-hospital complication rates varied throughout the study period, with no significant difference between African American and white patients:

    • 1.27% for African American patients versus 1.21% for white patients in 2007-08
    • 1.08% for African American patients versus 1.03% for white patients in 2011-12
    • 0.92% for African American patients versus 0.86% for whites patients in 2015-16

    Bella Mehta, MBBS, a rheumatologist at HSS, said the patient selection process could explain the study findings concerning complication rates, with a more rigorous patient selection process applied for same-day bilateral TKA than for unilateral TKA. With regard to the lower number of African Americans having the same-day bilateral TKA, Dr. Mehta said physicians may be offering it less often to African American patients or African American patients may not be choosing to undergo the same-day bilateral procedure.

    “Since the complication rate for bilateral knee replacement is not higher for African American patients, health providers should work to provide access to all appropriate patients,” Dr. Mehta said. She noted that future studies could take a closer look at the patient selection process or assess the role of an individual’s health insurance plan in utilization of the bilateral procedure.

    “As we seek to achieve health equity for our patients, we must understand the challenges they face in accessing care, as well as variance in their outcomes,” said Michael Parks, MD, an orthopaedic surgeon at HSS and one of the study authors. “Our ultimate goal is to provide the same quality of care to everyone.”


    Mehta B, Ho K, Bido J, Memtsoudis S, Parks M, Russell L, Goodman S, Ibrahim S. Bilateral vs Unilateral Total Knee Arthroplasty: Racial Variation in Utilization and In-Hospital Major Complication Rates. Abstract 1653. Presented at the ACR Convergence 2020, November 5-9, a virtual meeting.