ABSTRACT
Total hip and knee replacements (“total joint replacements” [TJRs]) are highly successful surgeries for
patients with end-stage arthritis. Despite their clinical benefits, racial/ethnic and socioeconomic disparities in
the use and outcomes of these surgeries are well-established. These disparities have persisted for decades
despite well-intentioned and effective disparity reduction strategies that have been locally implemented. In the
absence of a national reform that incentivizes disparity reduction, the vision of achieving TJR equity may
remain unfulfilled. Medicare’s 2016 Comprehensive Care for Joint Replacement (CJR) model is a bundled
payment reform aimed at improving quality and reducing spending for Medicare beneficiaries undergoing
TJRs. In 2021, the CJR was redesigned (rCJR) to include adjustments for social risk (dual-eligibility for
Medicare and Medicaid) and clinical risk (hierarchical condition category score and age) – measures that could
potentially reduce TJR disparities by ‘recognizing’ the higher spending for marginalized patients (many of
whom belong to racial/ethnic minority or lower socioeconomic groups, and are in poorer health). These
adjustments are likely to reduce incentives for hospitals to avoid operating on marginalized patients, provide
these patients access to high-quality hospitals, and increase quality/price competition between hospitals to
attract these patients; thereby promoting equity in TJR use and postoperative outcomes. In theory, the new risk
adjustment measures could potentially transform the rCJR into a national TJR disparity reduction strategy.
However, there is little empirical evidence to support our hypothesis. Thus, our objective is to evaluate rCJR’s
association with racial/ethnic and socioeconomic disparities in TJR use, outcomes, and spending, with a focus
on the performance of safety-net hospitals. We will use national Medicare data from 2018-2024 to evaluate
rCJR’s association with disparities in the use of TJRs (Aim 1) and in clinical metrics (Aim 2). We will also
examine whether the rCJR may have influenced TJR spending for marginalized patients (Aim 3). Our work is
significant because we will answer questions such as whether the rCJR was effective in reducing disparities,
which metrics were most influenced by the rCJR, and which institutions successfully reduced disparities. These
findings are critical for understanding whether and how the rCJR can be leveraged to reduce disparities
nationally, and for realizing the elusive target of equity in TJR care for patients with arthritis.
