Varus–valgus laxity correlates with pain in osteoarthritis of the knee

Pain during osteoarthritis (OA) of the knee does not necessarily correlate with the severity of the radiographic grade, and the mechanism of pain has not been completely clarified. The purpose of this study was to evaluate risk factors for pain in the knee OA using epidemiologic analyses.

We evaluated 518 out of 4183 people over the age of 40 (156 males and 362 females) from Shinyoshitomi village, Japan. Mean ages were 63.8 years for men and 60.7 years for women. Screening included a physical examination of the knee and a standing AP roentgenogram of the bilateral knee. Radiographic OA was defined as a Kellgren–Lawrence grade 2 or higher. All data were coded and pain risk factors were evaluated using a multiple logistic regression model.

Radiographic OA was observed in 18.4% of men and 26% of women. Of these subjects with OA, 10.9% of men and 32.5% of women complained of knee pain. Seven factors—age, gender, BMI, radiographic grade, varus–valgus laxity, torque of quadriceps muscles, and varus–valgus alignment—were evaluated as potential risk factors for pain. A significant increase in the odds ratio was observed with varus–valgus laxity ( p  = 0.005; odds ratio, 3.04). Our results suggest that varus–valgus laxity is a risk factor for pain during knee OA.