Differences in radiographic features of knee osteoarthritis in African-Americans and Caucasians: the Johnston county osteoarthritis project.

OBJECTIVE: To examine racial differences in tibiofemoral joint (TFJ) and patellofemoral joint (PFJ) radiographic osteoarthritis in African-American (AA) and Caucasian men and women.

METHOD: Multiple logistic regression was used to evaluate cross-sectional associations between race and tibiofemoral osteoarthritis (TF-OA) and the presence, severity and location of individual radiographic features of tibiofemoral joint osteoarthritis [TFJ-OA] (osteophytes, joint space narrowing [JSN], sclerosis and cysts) and patellofemoral joint osteoarthritis (PFJ-OA) (osteophytes, JSN and sclerosis), using data from the Johnston County Osteoarthritis Project. Proportional odds ratios (POR) assessed severity of TF-OA, TFJ and PFJ osteophytes, and JSN, adjusting for confounders. Generalized estimating equations accounted for auto-correlation of knees.

RESULTS: Among 3187 participants (32.5% AAs; 62% women; mean age 62 years), 6300 TFJ and 1957 PFJ were included. Compared to Caucasians, AA men were more likely to have TF-OA (adjusted odds ratio [aOR]=1.36; 95% CI, 1.00-1.86); tri-compartmental TFJ and PFJ osteophytes (aOR=3.06; 95%CI=1.96-4.78), and TFJ and PFJ sclerosis. AA women were more likely than Caucasian to have medial TFJ and tri-compartmental osteophytes (aOR=2.13; 1.55-2.94), and lateral TFJ sclerosis. AAs had more severe TF-OA than Caucasians (adjusted cumulative odds ratio [aPOR]=2.08; 95% CI, 1.19-3.64 for men; aPOR=1.56; 95% CI, 1.06-2.29 for women) and were more likely to have lateral TFJ JSN.

CONCLUSIONS: Compared to Caucasians, AAs were more likely to have more severe TF-OA; tri-compartmental disease; and lateral JSN. Further research to clarify the discrepancy between radiographic features in OA among races appears warranted.