Regional Implicit Bias Does Not Account for Racial Disparity in Total Joint Arthroplasty Utilization

Racial disparities surrounding the utilization of total hip and total knee arthroplasty (THA, TKA) are well documented. The Implicit Association Test (IAT) is a validated tool used to measure implicit and explicit bias. The purpose of this study is to evaluate if variations in IAT scores by geographical region in the United States (US) correspond with regional variations in THA and TKA utilization by blacks compared to whites.

Data from the US Census and National Inpatient Sample from 2012 to 2014 were used to calculate THA and TKA utilization rates among Medicare-aged blacks and whites. Data were aggregated by US Census Bureau Division. Regional implicit bias was assessed by calculating a weighted average of IAT scores for each division.

Across all geographic regions and years, the surveyed population demonstrated an implicit bias favoring whites over blacks. The population adjusted ratio of white-to-black utilization of THA and TKA by geographic division varied between 0.86-1.85 and 0.87-2.01, respectively. The difference in utilization between geographic divisions reached statistical significance (P < .001). No correlation was found between the IAT scores and race-specific utilization ratios among geographic divisions.

Implicit bias as measured by regional IAT did not reflect THA and TKA utilization disparities. The racial disparity in utilization of THA and TKA significantly varied between divisions. The observed disparity was greater in divisions with a relatively higher proportion of blacks. To the authors’ knowledge, this is the first study to evaluate the impact of implicit bias on utilization of THA and TKA.