Bowlegs

Also known as: Genu varum

Anatomy or system affected: Bones, feet, hips, joints, knees, legs, ligaments, muscles

Definition: A deformity of the legs that can be temporary or persistent, depending on causation.

Causes: Compression of limbs in uterus, bone diseases, genetic diseases, injuries, tumors, deformities, rickets, repetitive motions

Symptoms: Curving leg bones

Duration: Temporary or chronic

Treatments: Muscle exercises, vitamin D supplements, orthotic braces and shoes, surgical straightening

Causes and Symptoms

Bowlegs describes a condition in which a person standing with ankles and feet together has knees that do not touch and tibias and femurs that curve away from the body’s axis. Because of the compression of limbs in the uterus, babies are born with flexed hips and knee capsules with contracted fibers. Infants have rotated feet and legs, with tibias curving inward and femurs outward. As children mature, knee angles gradually acquire normal alignment because ligament fibers stretch and bones rotate to correct positions. If the legs do not straighten, a child’s movement will be hindered. These children may be susceptible to falling and walking pigeon-toed. Some children exhibit a single bowleg, with the other leg appearing straight.

Bone diseases, genetic conditions, injuries, tumors, and deformities can cause bowlegs to persist beyond childhood. Some babies are born with misshapen leg bones that curve. Blount’s disease (tibia vara) alters tibiagrowth in the plate adjacent to the knee, causing bowing. Environmental factors include inadequate nutrition resulting in rickets and conditions associated with deficient vitamins and minerals that are essential to healthy bone growth. Weak bones are more vulnerable to curve unnaturally. Repetitive motions such as kicking can change the strength and length of leg muscles. As a result, muscles can become uneven. When movement exerts pressure on knees and imbalanced legs, curvature is exacerbated.

Treatment and Therapy

Physicians assess the degree of a patient’s bowlegs by measuring the space between the legs while standing. They also observe the patient’s movement. Most mild cases occurring temporarily during normal childhood development do not require treatment. Legs can be manipulated to stretch fibers and rotate bones gradually to desired angles. Muscle exercises can prevent imbalances that make people susceptible to bowlegs. Vitamin D supplements can resolve bowlegs caused by rickets.

Doctors use X-rays to detect knee and leg bone structural flaws in older children whose bowlegs have not naturally straightened or have worsened. Braces and shoes are sometimes used to correct bowlegs. Most Blount’s disease patients constantly wear a corrective knee-ankle-foot orthosis (KAFO) to aid normal bone growth by reducing joint pressure. Surgical bone straightening occasionally is required for extreme cases of bowlegs. Pins are used to inhibit leg bone growth where it is abnormal. The osteotomy procedure adjusts the upper tibia. Some Blount’s disease patients require osteotomy if the KAFO does not alleviate their condition.

Perspective and Prospects

Philipp Erlacher documented Blount’s disease by 1922. Fifteen years later, Walter Blount differentiated between the infantile and adolescent types of that condition. Later researchers expanded knowledge of this condition and bowlegs, and using radiographic images, Anders Langenskiold and E. B. Riska classified six stages of Blount’s disease deformity.

Bibliography:

England, Stephen P., ed. Common Orthopedic Problems. Philadelphia: W. B. Saunders, 1996.

Hensinger, Robert N., ed. The Pediatric Lower Extremity. Philadelphia: W. B. Saunders, 1987.

Herring, John A., ed. Tachdjian’s Pediatric Orthopaedics. 6th ed. 3 vols. Philadelphia: Saunders/Elsevier, 2022.

Kaneshiro, Neil K. "Bowlegs." MedlinePlus, 31 Oct. 2022, medlineplus.gov/ency/article/001585.htm. Web. Accessed 31 July 2023.

Morrissy, Raymond T., and Stuart L. Weinstein, eds. Lovell and Winter’s Pediatric Orthopaedics. 8th ed. Philadelphia: Wolters Kluwer, 2021.