Study compares racial disparities in unilateral versus bilateral knee replacement

Disparities in unilateral knee replacement surgery have been well-documented, with lower utilization and higher complication rates among African American patients. While previous studies have focused on single knee replacement surgery, researchers at Hospital for Special Surgery (HSS) set out to determine if racial variations exist for same-day bilateral knee replacement, as well.

“In our retrospective analysis, we found the utilization rate of bilateral knee replacement was much lower in African American patients compared to white patients,” said Bella Mehta, MBBS, a rheumatologist at HSS. “On the other hand, although African Americans having unilateral knee replacement have been shown to have higher in-hospital complication rates compared to white patients, this pattern was not consistent for bilateral knee replacement during the time period we studied.” She presented the findings on November 9 at the American College of Rheumatology annual meeting, which took place virtually.

Dr. Mehta and colleagues compiled information from the National Inpatient Sample (NIS) – Healthcare Cost and Utilization Project (HCUP) database from 2007 to 2016. They looked at trends in utilization and major in-hospital complication rates of unilateral versus bilateral knee replacement nationwide in patients age 50 and older.

Investigators 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.

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

The researchers found that African Americans were much less likely to undergo a double knee replacement compared to white patients during the years analyzed. In-hospital complication rates varied throughout the study period, with no significant difference between African American and white patients.

To explain the study findings concerning complication rates, Dr. Mehta said there could be a more rigorous patient selection process when considering candidates for same-day bilateral knee replacement. Regarding the lower number of African Americans having the bilateral procedure, she said physicians may be offering it less often to African American patients or they may be choosing not to have the 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 orthopedic surgeon at HSS and study author. “Our ultimate goal is to provide the same quality of care to everyone.”

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HSS is the world’s leading academic medical center focused on musculoskeletal health. At its core is Hospital for Special Surgery, nationally ranked No. 1 in orthopedics (for the 11th consecutive year), No. 4 in rheumatology by U.S. News & World Report (2020-2021), and named a leader in pediatric orthopedics by U.S. News & World Report “Best Children’s Hospitals” list (2020-2021). Founded in 1863, the Hospital has the lowest complication and readmission rates in the nation for orthopedics, and among the lowest infection rates. HSS was the first in New York State to receive Magnet Recognition for Excellence in Nursing Service from the American Nurses Credentialing Center four consecutive times. The global standard total knee replacement was developed at HSS in 1969. An affiliate of Weill Cornell Medical College, HSS has a main campus in New York City and facilities in New Jersey, Connecticut and in the Long Island and Westchester County regions of New York State, as well as in Florida. In addition to patient care, HSS leads the field in research, innovation and education. The HSS Research Institute comprises 20 laboratories and 300 staff members focused on leading the advancement of musculoskeletal health through prevention of degeneration, tissue repair and tissue regeneration. The HSS Global Innovation Institute was formed in 2016 to realize the potential of new drugs, therapeutics and devices. The HSS Education Institute is a trusted leader in advancing musculoskeletal knowledge and research for physicians, nurses, allied health professionals, academic trainees, and consumers in more than 130 countries. Through HSS Global Ventures, the institution is collaborating with medical centers and other organizations to advance the quality and value of musculoskeletal care and to make world-class HSS care more widely accessible nationally and internationally. http://www.hss.edu.