19 Aug Knock Knee (Genu Valgum): Causes and Correction Options
Knock knee, medically known as genu valgum, is a condition where the knees angle inward and touch while the ankles remain apart, giving the legs a "knock-kneed" appearance when standing. Mild knock knee is extremely common in young children and is often a normal part of development that resolves on its own by around age seven or eight. Persistent or worsening knock knee, however, especially into later childhood or adulthood, is a different story and may need active treatment.
Causes vary. In children, it’s often simply a stage of normal skeletal development. In other cases, it can be linked to conditions affecting bone growth, prior injury to a growth plate, obesity-related joint stress, rickets or other metabolic bone conditions, or arthritis in adults. Because the underlying cause changes the treatment approach, an accurate diagnosis — usually involving standing X-rays to measure the exact angle of deformity — is essential before deciding on a plan.
For children with growth remaining, guided growth surgery is often the first-line option once knock knee is confirmed to need correction. This involves placing a small plate across part of the growth plate on the inside of the knee, which temporarily slows growth on that side while the outside continues normally, gradually straightening the leg as the child grows. It’s a minimally invasive outpatient procedure, and the plate is removed once correction is achieved.
In adults, or in children who have finished growing, guided growth isn’t an option since the growth plates are closed. Correction instead requires an osteotomy (also called an acute deformity correction) — a precise surgical cut in the bone near the knee, which is then repositioned into proper alignment and secured with a plate, screws, an internal nail, or an external fixator while it heals.
Left uncorrected, significant genu valgum can accelerate wear on the outer compartment of the knee joint, contributing to earlier arthritis. That’s part of why surgeons weigh not just the current appearance of the legs, but the long-term load pattern on the joints when recommending treatment.
This article is for general educational purposes only and does not constitute medical advice. Every patient’s anatomy, goals, and treatment plan are different. Please consult a qualified orthopedic surgeon to discuss whether any procedure described here is appropriate for you.
