New Insights into Racial Disparities in Revision Total Knee Arthroplasty
Although the risk of revision after total knee arthroplasty (TKA) is low overall at about 1% to 2%, the risk for Black patients is known to be higher than for white patients. How that translates to risk for septic versus aseptic revision, however, has been unknown.
Until now: New research from Hospital for Special Surgery indicates that compared with white patients, Black patients have an 11% higher risk of septic revision for infection and a 39% higher risk of aseptic revision related to pain, instability, or loosening.
For the study, the researchers examined data for nearly 725,000 patients who had undergone TKA between 2004 and 2014 in California, Florida, and New York. Their analysis included a range of variables that have been linked to risk of revision TKA in previous studies: age, sex, insurance status, presence of comorbidities (diabetes, obesity, renal disease, chronic obstructive pulmonary disease [COPD], inflammatory arthritis], surgical site complications, infection on admission for TKA, and hospital factors (non-government, not-for-profit, or teaching hospital; rural location; number of beds; annual TKA volume).
The researchers found that in addition to being Black, factors associated with a higher risk of septic revision TKA were:
- Comorbidities: diabetes, obesity, renal disease, COPD, inflammatory arthritis
- Surgical site complications
- Medicaid insurance
- Low-volume hospital
Similarly, for aseptic revision, additional risk factors were:
- Male sex
- Workers’ compensation insurance
- Low-volume hospital
When the researchers analyzed the data according to different categories of hospital volume, they discovered that Black patients had a 20% higher risk of aseptic revision TKA than white patients if they underwent replacement at low-volume hospitals, defined as 89 or fewer total knee replacements annually. However, the risk rose to 68% for those who had TKA at very high-volume hospitals, defined as 645 or more procedures per year.
“As we predicted, the risk factors were very different for patients needing aseptic versus septic revision,” said lead study author Anne R. Bass, MD, an Attending Physician in the Division of Rheumatology at Hospital for Special Surgery. “But we were totally surprised to find Black race was one of the only risk factors associated with aseptic revision and that this disparity was so much higher for patients treated at high-volume hospitals.
“The question now is why do these disparities exist,” she said. “Our study did not reveal causes, but we can use this learning to develop theories for further investigation.”
Study co-author Michael L. Parks, MD, Clinical Director of Orthopedic Surgery and Vice Chair for Quality at Hospital for Special Surgery, noted that, “Black patients tend to bypass larger, higher-volume hospitals and have surgery at lower-volume hospitals. One of the reasons why they may have higher revision rates at higher-volume hospitals is that they tend to present later with more advanced disease and require more complicated surgeries than white patients.”
Added Dr. Bass, “The other hypothesis is that care is not being delivered equally across patient groups at high-volume hospitals. If that’s the case, hospitals should review and ensure care processes are accessed and applied equally across racial groups to improve surgical outcomes.”
Dr. Bass, Dr. Parks, and their colleagues are currently conducting further research to investigate whether there is a relationship between revision TKA risk, hospital volume, and annual volume by surgeon.
Bass AR, Do HT, Mehta B, et al. Assessment of racial disparities in the risks of septic and aseptic revision total knee replacements. JAMA Netw Open. 2021 Jul 1;4(7):e2117581. doi: 10.1001/jamanetworkopen.2021.17581.