This study aimed to determine whether the distance between the medial epicondyles of the femur is useful as a screening test for varus knee. The participants were 53 community-dwelling older adults. First, a receiver operating characteristic (ROC) curve analysis was performed to obtain the cutoff value for the distance between the medial epicondyles of the femur. The cutoff values and femorotibial angle (FTA) were used to compare body composition and physical function between the groups. The cutoff value for the distance between the medial epicondyles of the femur was 2.75 cm. The intergroup comparison based on the FTA revealed significant differences in lower-limb muscle mass, grip strength, and quadriceps muscle strength. The results of the cutoff value-based comparison showed significant differences in skeletal and lower-limb muscle mass, grip strength, and quadriceps muscle strength, all of which were consistent with each other. Measuring the distance between the medial epicondyles of the femur is a useful screening test for varus knees in community-dwelling older adults.