African-Americans less likely to have varus thrust, more likely to have valgus thrust than Caucasians
April 16, 2016
The study revealed that 32.1% of subjects without OA and 36.7% of those with OA had a varus thrust. Valgus thrust was less frequent: 7.2% without OA and 9.1% with OA. The odds of varus thrust were significantly less for African-Americans compared to Caucasians in both disease subgroups, after controlling for other factors. Other factors associated with varus thrust presence in persons without knee OA were age, BMI, varus malalignment, gender (reduced odds in women), and knee extensor strength (reduced odds with greater strength), and, in persons with knee OA, more severe OA disease, varus malalignment, and gender (reduced odds in women).
The odds of valgus thrust were significantly greater for African-Americans compared with Caucasians, in persons without and with knee OA. Also associated with valgus thrust presence in persons without knee OA were valgus malalignment and, in persons with knee OA, more severe lateral disease and valgus malalignment.
"To our knowledge, this is the first report on the frequency of varus and valgus thrust in African-Americans and Caucasians either in persons with or at higher risk of developing knee OA," Dr. Sharma commented. "Further investigation of methods to quantify the elements of a thrust, such as its force and loading rate, will enhance understanding of the mechanism of a thrust effect," concluded the authors. The researchers also caution that persons without knee OA in the OAI thrust study were at high risk of developing it, and thus frequency estimates should not be applied to the general population.