This information reflects U.S. guidance; if you live elsewhere, follow local emergency guidance and check with a local pediatrician.
Why It Happens
Most toddlers under about age 2 have legs that curve outward at the knees, a pattern doctors call bowlegs or genu varum, and the American Academy of Orthopaedic Surgeons (AAOS), through its OrthoInfo patient education resource, explains that this is simply a normal variation left over from how a baby was folded up in the womb. As growth plates at different parts of the leg bones grow at different rates over time, the overall alignment of the legs naturally shifts through several stages before settling into an adult pattern. A less common but more serious cause is Blount’s disease, in which the growth plate at the top of the shinbone develops abnormally; unlike ordinary physiologic bowing, AAOS notes that Blount’s disease does not resolve on its own and tends to worsen rather than improve over time.
How It Looks at Different Ages and Stages
AAOS describes physiologic bowlegs as typically starting to improve around 18 months of age and largely resolved by about age 3 to 4, at which point many children swing the other way into knock-knees (genu valgum), which peaks around the same age before gradually straightening. HealthyChildren.org, published by the American Academy of Pediatrics, offers a somewhat broader timeline: many children have bowlegs until about age 2, followed by a knock-kneed appearance that can last until around age 6, with some children not fully straightening out until age 9 or 10, though the legs typically look adult-like well before the teenage years.
Home Care
Standing a child up straight and checking, every few months, how far apart the knees are when the ankles are touching, or how far apart the ankles are when the knees are touching, and comparing photos taken every 3 to 6 months, is a simple way to track whether the pattern is following the expected course. What matters most is whether both legs look similarly affected and whether things are gradually improving over time; when the pattern is physiologic, this kind of watching is really all that’s needed. Buying corrective shoes or leg braces on your own because the legs look unusual isn’t recommended; if you’re worried, a doctor visit to weigh the actual need is the safer route.
Common Parent Misconceptions
A common belief is that too much time in diapers causes bowlegs, but leg curvature is a normal consequence of fetal positioning and bone growth, unrelated to diaper use. Many parents also assume that unusual-looking legs need to be fixed right away with corrective shoes or braces, but HealthyChildren.org states plainly that bracing, corrective shoes, and special exercises do little for ordinary physiologic bowlegs or knock-knees and can even get in the way of a child’s normal development or cause needless stress, and AAOS takes the same position. Rushing to correct the legs quickly when the pattern is simply physiologic isn’t necessary; both organizations agree that watching and waiting is generally sufficient.
Signs That Need Medical Care
See a pediatric orthopedic specialist if bowlegs don’t improve after age 2 and instead seem to be getting worse, if knock-knees are still present after age 7, or if one leg is noticeably more curved than the other. Leg curvature paired with unusually short stature for a child’s age, pain while walking, a leg-length difference, or a limp can point to Blount’s disease, rickets, or another underlying cause that needs an X-ray to sort out. Obesity combined with bowlegs that keep worsening past age 3 is a recognized risk factor for Blount’s disease, so that combination is worth getting checked without delay. Leg curvature itself is rarely a true emergency, but a sudden change in leg shape after an injury, or severe pain that keeps a child from bearing weight on the leg, could mean a fracture, and that calls for an emergency room visit right away. This information isn’t a diagnostic tool and doesn’t replace advice from a medical professional.