Background/Purpose: Literature reports sizable improvements in pain and function in patients having undergone Total Knee Arthroplasty (TKA) procedure. However, significant disparities exist in the utilization of this procedure by racial groups. Hence, the aim of this study is to evaluate the role of race on TKA outcomes.

Methods: Patients were recruited from 2 orthopedic clinics. Outcomes measured included: i) WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) measuring pain, stiffness and function (higher scores=worse outcomes), ii) SF-36 measuring mental (MCS) and physical (PCS) health status. Scores at baseline, 6 and 24 months were generated and absolute change (D= Baseline score – 6/24 months score) was calculated. ANOVA was used to determine whether: scores at baseline, 6 and 24 months, independently, varied among the racial groups and; the absolute and percent change scores (at 6 and 24 months) varied among the racial groups. Multiple regression analysis was conducted to evaluate the association of race and other demographic characteristics with 6 and 24 months TKA outcomes; with and without controlling for baseline outcomes.

Results: 247 of 615 patients screened completed baseline of which 241 completed 6 months and 178 completed 24 months assessments. Of the 247; 162 (66%) were females, 114 (46%) were <65 years, 172 (70%) were White, 62 (25%) were African American and, 11 (4%) were Hispanic. Although African Americans compared to Whites had consistently greater pain and function WOMAC scores at all three time periods, this difference was statistically significant only pre-operatively (pain- 62 vs 52, p<0.05 and function- 62 vs 52, p<0.05). With respect to SF-36 scores: compared to Whites, Hispanics had significantly lower MCS scores (55 vs 48, p<0.05) only at 6 months, whereas, neither clinically nor statistically significant differences in PCS scores were observed between the two groups at any time period. In regards to absolute change: African Americans compared to Whites, experienced greater improvements in pain (D: 41 vs 33, NS) and function (D: 40 vs 20, p<0.05) which was not observed at 24 months. In spite of adjusting for age, gender, marital status, educational attainment and baseline outcomes; being Hispanic was still associated with lower MCS scores (p=0.02) at 6 months, and being African American was still associated with lower functional status at 24 months (p=0.04). 

Conclusion: When compared to Whites, African American patients started out with a lower preoperative status. Yet, they achieved greater gains in pain and function than White patients, within 6 months. However, by 24 months these improvements leveled off such that no significant difference in change was observed between the two groups. Controlling for demographic characteristics and baseline outcomes, ethnicity was predictive of TKA outcomes such that; being Hispanic was associated with lower mental health at 6 months and being African American was associated with poorer functional status at 24 months. Further research is needed to explore potential behavioral and psychosocial determinants that explain reduced pain and functional outcomes in African American patients.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/ethnic-variations-at-time-of-surgery-and-during-follow-up-in-patients-undergoing-total-knee-arthroplasty/