Most babies are born with bowed legs. That means if you stand your baby up with ankles together, the knees bow outward and don’t touch, like a cowboy in an old western. This is a normal condition for babies and for toddlers called physiologic genu varum. The bowing affects both legs and is symmetrical.
This type of bowed legs usually corrects itself by age 3 and almost always by age 4 or 5. Physiologic genu varum does not affect a baby’s ability to stand or start walking, although bowed legs may be more obvious when a toddler starts to walk. Toddlers with bowed legs may also walk or stand with their feet pointed inwards (pigeon toed). This is also normal and will correct as the bowing improves.
Abnormal Causes of Bowed Legs
Bowing that only occurs in one leg or bowing that does not improve with age may be a sign of a condition that needs to be treated. The most common cause is a disease called Blount’s Disease. Children with Blount’s disease have abnormal growth at the knee end of the shinbone, an area called a growth plate. The growth plate may be allowing growth of the shinbone only on one side which causes the knee to bend outward. Blount’s disease becomes more severe by age 3, instead of better.
A very rare cause of bowed legs is rickets. Rickets is bone weakness caused by a deficiency in calcium or vitamin D. Because children in the U.S. get plenty of calcium and vitamin D in their diet, rickets is unlikely. There is also a rare cause of rickets that is passed down through families. This genetic defect prevents absorption of vitamin D from the diet.
Finally, some children who are overweight as toddlers may continue to have physiology genu varum into their adolescent years. The extra weight may prevent natural correction.
Diagnosis and Treatment of Bowed Legs
If you child has symmetrical bowed legs and is under age 2, your doctor will just keep checking for correction. No treatment is needed. If your child has one-sided bowing, severe bowing, or bowing that is not improving after age 2, x-ray imaging of the knees may be done. Blount’s disease may be diagnosed at this time. Rickets can also be seen on x-ray and confirmed with blood testing for calcium and vitamin D.
Toddlers with physiologic genu varum do not have any pain or other symptoms, but children who have bowed legs that continue into adolescent years may have trouble walking and trip frequently. Bowed legs may also put pressure on the hip, knee, and ankle joints causing pain.
Treatment for children who continue to have bowed legs after age 4 or 5 may start with bracing. Overweight children may need to lose weight. Treatment may start even earlier for children diagnosed with severe bowing. Treatment for rickets is vitamin therapy with calcium and vitamin D. In rare cases, surgery is need to correct bowing. One type of surgery (guided growth surgery) straightens the leg by reconstructing the growth plate. A more advanced surgery for older children reconstructs the shinbone.
For the vast majority of children who start walking like a little cowboy with bowed legs, treatment will never be needed. Your child’s doctor will be checking for physiologic genu varum during your routine visits, but if your child continues to have bowed legs after age 2, ask your child’s doctor if an x-ray should be done to rule out other causes of bowed legs.