Also known as genu varum, bowlegs are an outward curve of the upper half (femurs) and lower half (tibias) of the leg bones. The result is a bow-shaped appearance in your baby’s legs when they’re standing with their feet and ankles together. Their knees do not meet while in this position. Alternatively, when their knees meet, but their ankles do not, they would be diagnosed as knock-kneed rather than bowlegged.
Note that toddlers who are learning to walk often appear bowlegged as they sway from side to side before gaining enough confidence to move forward. More often than not, the problem spontaneously disappears without treatment by the age of 2.
Typically, the physiological condition of genu varum is caused by cramped conditions inside the womb. The curled position that a fetus is forced to adopt within the uterus encourages the development of bowlegs, osteomalacia, and/or rickets.
In certain cases, bowlegs could be the direct result of rickets (defective mineralization of cartilage in the growth plates). Symptoms of rickets include pain and weakness in the bones, delayed growth, and even deformity. Vitamin D and calcium deficiencies are generally to blame.
Vitamin D is essential to maintaining strong, healthy bones. According to the FDA (Food and Drug Administration), infants should consume a maximum of 400 IU of vitamin D per day. While the human body’s able to produce its own vitamin D with the help of sunlight, it’s also found in eggs and oily fish.
Aside from rickets, however, there are other possible explanations behind bowlegs.
- Blount’s disease (or tibia vara), which presents complications like meniscal tears, gait abnormalities, and osteoarthritis (OA). It normally requires orthopedic treatment and monitoring to improve prognosis and quality of life.
- A vitamin D deficiency due to poor diet and lack of sun exposure, inflammatory bowel disease, or gastrointestinal bypass surgery. Sometimes, a genetic predisposition for vitamin D resistance or a chronic illness (e.g., kidney disease) lies at the root of the problem.
- Bone dysplasia and improperly-healed fractures have been known to lead to bowlegs, and in rare cases, lead or fluoride poisoning may be the culprit.