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Not all Limbs are Created Equal

Nov 18, 2019

Bazzi, AhmedMany people might find it surprising that a large percentage of individuals have slight differences in the length of their arms and legs.  In fact, according to the American Academy of Orthopaedic Surgeons, one study reported that 32 percent of 600 military recruits had a 1/5 inch to a 3/5 inch difference between the lengths of their legs.

When the differences are minor, treatment is not needed. But children who have greater differences, especially in the legs, may require limb lengthening and limb correction surgery to help correct irregular bone growth that occurred before birth or in childhood.  Other causes of growth disturbances that may require treatment include infection, trauma, fractures, tumor removal or paralysis.

When a child has a significant arm or leg length discrepancy or deformity, his or her quality of life and the ability to perform many day to day physical activities can be affected. Complications may include back, hip, and knee problems as the child grows.

Treatment Options

The decision to treat a limb length discrepancy depends on the amount of difference there will be when the child stops growing,” says Ahmed Bazzi, D.O., pediatric orthopedic surgeon at Children’s Hospital of Michigan at the Detroit Medical Center.

Depending on the amount of discrepancy between the limbs, treatment options can vary from wearing a shoe lift to various surgeries to shorten or lengthen the limb.

A lift fitted to the shoe can often improve walking and running, as well as relieve any back pain that may be caused by the limb length discrepancy. Shoe lifts are inexpensive and can be removed if they are not effective.

In growing children, legs can be made equal or nearly equal in length with a relatively simple surgical procedure which slows the growth of the longer leg at one or two growth sites. The procedure is performed under X-ray control through small incisions in the knee area. With this procedure the limb length discrepancy will gradually decrease as the opposite extremity continues to grow.

Ideally treatment should be timed to reach equal leg length by the time growth normally ends, usually in the mid-to-late teenage years. In some cases the longer leg can be shortened, but a major shortening may weaken the muscles of the leg. In the thighbone (femur), a maximum of three inches can be shortened. In the shinbone, a maximum of two inches can be shortened.

Surgical lengthening of the shorter leg is another option. The bone is lengthened by surgically applying an external fixation device to the leg. The external fixator is connected to the bone with wires, pins, or both. A small crack is made in the bone and the frame creates tension when the patient or family member turns its dial. This is done several times each day. The lengthening process begins approximately five to 10 days after surgery. The external fixator is worn until the bone is strong enough to support the patient safely. This usually takes about three months for each inch of lengthening. 

The latest in internal fixators includes an internal lengthening device (nail) that provides stabilization as new bone grows to lengthen the tibia and femur to a preset length.  The nail has a special magnet built inside of it which gets longer using an external machine that the child puts on their leg at home on a daily basis. 

“At Children’s Hospital of Michigan we use some of the latest technology to correct deformities and discrepancies. Advanced techniques and treatment plans such as external and internal fixators can produce life-changing results for affected children,” says Dr. Bazzi.