Medicare’s CJR Program May Have Helped to Reduce Some Racial Disparities After TJA

The introduction of Medicare’s Comprehensive Care for Joint Replacement (CJR) Model – intended to improve care for patients undergoing total hip or total knee arthroplasty – has led to reductions in some outcome disparities for Black patients compared with white patients, suggests a study published online ahead of print by The Journal of Bone & Joint Surgery.

Specifically, researchers from the Icahn School of Medicine at Mount Sinai in New York found that a reduction of racial differences in hospital readmission rates after total joint arthroplasty coincided with the rollout of the CJR Model in 2016.

Study Methods and Findings

Using the nationwide Medicare claims database, the researchers identified nearly 1.5 million total hip and total knee arthroplasty procedures performed between 2013 and 2018. About 5% of the patients (74,390) were Black.

The researchers recorded:

  • Preoperative characteristics: Age, sex, comorbidities
  • Hospitalization characteristics: Hospital length of stay, blood transfusions, complications
  • Postoperative characteristics: Readmission rates at 90 and 180 days, patient discharge disposition
  • Medicare payments

When they analyzed these data points, the researchers found substantial racial differences in patient characteristics, outcomes, and Medicare payments before and after implementation of the CJR Model. As a group, Black patients:

  • Had higher rates of comorbidities
  • Received more blood transfusions
  • Had longer lengths of stay in the hospital
  • Were more likely to be discharged to an institution (such as a skilled nursing facility) than directly home

The CJR program led to improvements in several key outcomes, some of which differed by race. After adjustment for other factors, Black patients were found to have had larger reductions in 90-day and 180-day hospital readmission rates than white patients after implementation of the CJR Model. However, Medicare payments related to outpatient care were also lower.

White patients were found to have experienced reductions in length of hospital stay, complication rates, risk of hospital readmission within 90 and 180 days, and discharge to institutional care after implementation of the CJR Model. In addition, white patients experienced a reduction in Medicare payments to skilled nursing facilities.

“This Is an Important Finding”

The greater reduction in 90-day and 180-day hospital readmission rates among Black patients suggests that the CJR program has improved some pre-existing racial differences. “These observed racial differences may represent true ‘disparities’ as some may not be attributable to clinical factors and may be directly associated with poorer outcomes,” the researchers write.

Senior author Calin Moucha, MD, commented that “this is an important finding, as it provides insights on how to effectively reduce these disparities that we know are widespread, not just on orthopaedics, but in medicine in general.”

Jashvant Poeran, MD, PhD, another study author, said that “these results indeed seem promising, but we do have to consider alternative perspectives and explanations of our results. For example, although the effects on readmission rates are promising, the difference in payments for outpatient care – where we saw lower Medicare payments for Black patients – may also indicate potential under-utilization of post-discharge care in certain subgroups.”

Together with some previous reports of outcomes after introduction of the CJR Model, the new findings “support the notion of adapting and leveraging the bundled payment program design to reduce disparities in [total hip and knee replacement] care and outcomes,” the researchers said.

They noted that their study could not demonstrate a causal relationship between the CJR Model and the observed improvements in patient outcomes. “A first step toward reducing racial differences that represent disparities […] is to understand the sources of these disparities,” they said.

The researchers called for further studies to evaluate the potential of bundled payment models to reduce racial disparities, and the mechanisms by which they do so.


Okewunmi J, Mihalopoulos M, Huang H-H, Mazumdar M, Galatz LM, Poeran J, Moucha CS. Racial differences in care and outcomes after total hip and knee arthroplasties: did the comprehensive care for joint replacement program make a difference? J Bone Joint Surg Am. 2022 April 15. Online ahead of print. doi: 10.2106/JBJS.21.00465

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