Genu valgum, commonly called "knock-knee", is a condition in which the knees angle in and touch each other when the legs are straightened.

[1] Individuals with severe valgus deformities are typically unable to touch their feet together while simultaneously straightening the legs.

Genu valgum can arise from a variety of causes including nutritional, genetic, traumatic, idiopathic or physiologic and infectious.

[3] Nutritional rickets is an important cause of childhood genu valgum or knock knees in some parts of the world.

Usually, limb reconstruction procedures are needed, especially if trauma occurs in the early years of life where the anticipated remaining longitudinal bone growth is great.

Bone corrective osteotomies and prosthetic joint replacement may be used depending upon the patient's age and symptomatology in terms of pain and functional impairment.

Working with a physical medicine specialist such as a physiatrist, or a physiotherapist may assist a patient in learning how to improve outcomes and use the leg muscles properly to support the bone structures.