Association of isometric hip abductor strength with Kellgren-Lawrence grade among patients with bilateral knee osteoarthritis

Abstract

Objectives: The degree of knee osteoarthritis (OA) is usually graded with the Kellgren-Lawrence (KL) grading system. Studies have shown the effect of weak hip abductor muscle as a contributory factor to knee OA. However, there is a shortage of literature regarding the association of hip abductor strength with the KL grade. Methods: Individuals diagnosed with bilateral knee OA between the ages 40 and 70 years, who have had a recent knee radiograph and are mobile and willing to participate, were included in the study. A brief demographic and basic screening was done following which the isometric hip abductor strength of each limb was assessed using the Jamar Handheld Dynamometer in a supine lying position across the wall. Three readings were taken, and the average was noted. The grade of OA was noted using the knee radiograph using the KL grading system. Results: Forty participants with bilateral knee OA were recruited for the study of which 62.5% (n = 25) were female and 37.5% (n = 15) were male. There was a weak negative correlation of KL grade of the left knee with the left hip abductor isometric strength (P = 0.013, r = −0.39). However, a statistically significant difference (P = 0.021) was found in isometric hip abductor strength between lower grade of knee OA (KL grade 1, 2) and higher grade of knee OA (KL grade 3, 4). Conclusion: There is an association between the isometric hip abductor strength and KL grade of knee OA wherein the better the strength, the lower the KL grade.