Leg length discrepancy describes the presence of legs that vary in length. This is a common deformity that has no effect on the function of the legs in very mild cases. However, larger variations can affect mobility and cause other issues.
When the limb length difference causes back pain or exceeds 2 cm (¾ of an inch) then treatment can and likely should be offered. A shoe lift, slowing down the growth of the opposite long limb in children, using external devices to lengthen or using internal rods to lengthen the short bone are all treatment options. There have been so many incredible advances making limb lengthening safe and doable even for very large discrepancies.
During limb lengthening, physical therapy is essential to stretch and maintain joint health. I cannot emphasize this enough.
If the discrepancy is large enough, the legs may be visibly different in length. A leg length discrepancy may also result in an abnormal gait, difficulty walking, and lower back pain.
A leg length discrepancy can occur naturally as the legs develop. Other cases may occur as a result of an injury of the leg bones and/or growth plates, bone disease, bone infection, or in association with a hip condition.
The first step in diagnosing a leg length discrepancy is observation and a physical exam which may include assessing the level of a child’s hip and their gait while walking. CT scans and x-rays may also be ordered to assess the severity and possible cause of the leg length discrepancy.
A minor leg length discrepancy that does not affect a child’s mobility or is not associated with any other conditions may not require any treatment. Shoe lifts may be recommended for smaller discrepancies. Surgical treatment such as limb-lengthening surgery is only recommended in severe cases. Modalities such as internal lengthening rods called Stryde Nails have revolutionized the care and allow even weight bearing while lengthening.