Genu valgum, known as knock-knees, is a knee misalignment that turns your knees inward. Genu valgum is common in young children and usually corrects itself as they grow. Genu valgum can also develop later in life from: an injury or infection in your knee or leg, severe lack of vitamin D and calcium, obesity, arthritis in the knee. This condition can’t be prevented, but its effects can be minimized. Physical therapy and exercise are often a successful alternative to surgery. Keep reading to learn more. Genu valgum that persists beyond childhood may have other symptoms like stiff joints, knee pain, walking with a limp.