Leg Length Discrepancy

What is Leg Length Discrepancy?

Leg length discrepancy occurs when one leg is shorter than the other. About 90% of the population has leg length discrepancy greater than 1.0 cm. Issues start to arise as the difference in length increases. Leg Length discrepancy can be either anatomical/structural or functional.

The anatomical/structural type occurs due to an asymmetry in the length of the leg bones. This can exist in the femur (thigh-bone) or tibia (shin-bone) in a child’s legs. There is usually no known cause for leg-length discrepancy. In some cases, it may be due to minor birth or developmental defects, genetic factors, fractures/trauma, or bone infection.

The functional type occurs when there is another issue that causes an asymmetry in the leg length. Some potential causes of this asymmetry include muscle tightness, weakness, skeletal misalignment, or joint contractures (shortening of muscles, tendons, ligaments, and joint capsules).

What are the symptoms of leg length discrepancy?

Parents will often notice that their child has posture or gait issues. These include having a tilted shoulder or a limp. Children may complain of back, hip, knee, or ankle pain. The difference in leg length may be visible, but is not usually obvious.

How is leg length discrepancy diagnosed?

Leg-length diagnosis is made through a series of physical tests and x-ray imaging. Physical tests include watching how the child walks and/or runs. X-ray is used to identify the type of discrepancy, as well as the specific length difference.

How is leg length discrepancy treated?

Treatment varies depending on the difference in leg length. Mild cases may be monitored over the course of the child’s life. If symptoms develop, options for treatment are normally non-surgical. These options include physical therapy or “lift therapy”. Lift therapy is when the child’s shoe is altered to minimize the length difference.

Surgical consultation is necessary when length discrepancy is more than 2 cm. It is important to have a conversation with your child’s doctor to consider what options are available.