Bowlegged

Bowlegged, or genu varum, is a condition in which the knees stay widely separated when the ankles are together, giving the legs a bow-like appearance. It can occur in infancy and childhood as a normal variant and may persist or develop into a deformity if an underlying condition is present.

In infants and young children, mild bowing is common and often resolves spontaneously by about ages 2 to 4. When bowing is persistent, progressively worsens, or is accompanied by pain or functional limitation, evaluation is warranted. Possible causes include rickets (vitamin D deficiency), Blount disease (disorder of growth of the proximal tibia leading to varus deformity), bone dysplasias, metabolic bone disorders, or sequelae of fractures. In adults, genu varum is more likely related to degenerative osteoarthritis, prior injuries, or malunions that alter leg alignment.

Diagnosis relies on history and physical examination, followed by imaging. Standing full-length or hip-to-ankle radiographs are used to assess leg alignment and measure angles such as the mechanical axis and knee varus angle to determine severity and guide treatment.

Management depends on age, etiology, and severity. Physiologic bowing in children typically requires observation. Nutritional or metabolic treatment may be needed for deficiencies. For mild deformities, bracing and physical therapy can help guide growth. In growing children with progressive deformity, guided growth using hemiepiphysiodesis can correct alignment gradually. In skeletally mature patients or severe cases, osteotomy to realign bone segments may be performed.

Prognosis is generally favorable for physiologic bowing, which often improves with growth. Pathologic bowing requires timely treatment to reduce pain, improve function, and lower the risk of early knee degeneration.