Bow legs, also known as genu varum, is a condition in which a person's legs become abnormally curved outwards. This can sometimes be part of a normal growth pattern and disappear over time, but it can sometimes cause long-term problems. In these cases, the bowing is generally caused by an underlying disorder that worsens over time. This can cause chronic pain, difficulty walking, deformity, and early onset arthritis.
The main symptom of bow legs is their distinctive appearance, in which a person's knees remain wide apart when he stands with his feet together. Age is also an important consideration. Since many young children have a natural rounded shape to their legs, a person is not considered to have a medical problem unless the legs don't straighten out by the time he is three or four years old. If the condition continues, then a person will likely have knee and hip pain, an awkward gait, and a tendency to turn the toes inwards while walking, and be prone to tripping.
Bowing that doesn't naturally resolve itself can be caused by a few different things, including Blount's disease, rickets, tumors, and injuries. Blount's disease is a condition in which the shin bones turn inwards, causing a curve primarily below the knees. It's not know what causes it, but it tends to be more common in those of African ancestry. It happens much more quickly than regular bowing, and often happens in only one leg. Though it is treatable, an early diagnosis is important, as the legs can become increasingly and permanently deformed if not treated.
Another common cause of bow legs is rickets, which is a condition caused by a vitamin D deficiency. In this case, the curve tends to happen in both legs, since the lack of vitamin D causes bones to get soft. Like Blount's disease, rickets is treatable, but can lead to permanent deformity if it's not addressed promptly.
Genetic disorders, skeletal infections, and tumors may also contribute to being bow legged. This includes things like Paget's disease of the bone, osteogenesis imperfecta, arthritis, and bone cancer. Some people are also prone to bow legs because of their occupation — for instance, jockeys often get them — or develop them because of an injury, like a leg fracture that heals improperly.
People with bow legs are generally more likely to develop arthritis at an early age, particularly if arthritis runs in their family. In these cases, their posture places abnormal pressure on the knee and ankle joints, which creates joint inflammation. This can degrade the cartilage and tissues around the joint, and lead to problems walking. Besides arthritis, people with bow legs tend to have chronic pain and inflammation of their ankles, knees, and hips that can lead to problems with posture and walking. Additionally, they may suffer psychological pain from bullying about their appearance.
Prevention and Treatment
Though many cases of bow legs can't be entirely prevented, it is possible to lower the risk of getting them or decrease their severity by getting good nutrition and consulting a health care professional regularly about any problems with the legs. Those at risk for rickets can take calcium supplements, spend time in the sun, and consult a metabolism specialist for help.
The treatment for bow legs largely depends on the underlying cause. If the curve is very minor, then treatment may be unnecessary. In those with Blount's disease, braces or splints are usually tried first to realign the shin bones, but surgery may be needed to truly correct the alignment of the leg. Rickets is generally treated with braces and supplements to help the bones become hard again, though braces may not be used for very young children, since they could cause their bones to develop abnormally.