Why Do Bow Legs Develop?

The medical term is genu varum. With the ankles together and kneecaps facing forward, the knees remain apart because the legs curve outward. The reason cannot be identified reliably from appearance alone; age, change over time, walking pattern and examination all matter.

Some bowing is part of normal leg development in babies and young toddlers and becomes less noticeable as growth changes alignment. A clinician looks beyond the gap between the knees: both sides should be compared, and the hips, knees, ankles and foot position may influence the overall appearance.

Bowing that persists, progresses or is clearly different between the legs can have another explanation. Possibilities include a growth-plate problem, altered bone strength, a previous injury or an underlying bone condition. In an adult, longstanding alignment or changes related to the knee joint may be relevant. These causes need different management, so self-diagnosis from photographs is unreliable.

Observe whether the curve is equal on both sides and whether it is changing. For a child, note any limping, frequent falls, difficulty keeping up, pain or reduced movement. A photograph taken occasionally from the front, with the child relaxed and the kneecaps facing forward, can help a clinician understand the trend without repeatedly measuring at home.

Arrange a routine medical assessment if the bowing concerns you or is not becoming less obvious with growth. The clinician may examine walking and joint movement, review growth and nutrition, and decide whether imaging or blood tests are appropriate. Special shoes, braces, supplements or exercises should not be started solely to change alignment without a diagnosis.

Book an earlier review if only one leg is affected, the curve is becoming more pronounced, walking is deteriorating, or there is persistent pain, swelling or stiffness. Also mention poor growth, unusual weakness or a history of significant leg injury because these details can change the assessment.

Seek urgent care after a new injury if the person cannot bear weight, the leg looks newly deformed, or there is severe pain. Fever with a hot, swollen joint or a child who appears acutely unwell also warrants prompt medical attention.

Ask whether the alignment matches the expected pattern for this age, whether both legs are developing similarly, and what changes should trigger reassessment. You can also ask what the examination suggests, whether any tests are needed and whether activity should continue as normal.