Have you ever been told or noticed that one of your legs is a bit longer than the other? Do you have incidences of lower back pain? These two things could be related. Most individuals have a small difference in their leg lengths. For some, the discrepancy is small and negligible and will not be a contributor to lower back pain. This is usually the case for people if their leg length is less than 5 millimeters. However, a difference of leg lengths greater than 5 millimeters (1/4 inch) can contribute to lower back pain. If you have a leg length difference of greater than 9 mm, then you have a 6X greater likelihood of having an episode of lower back pain.
LLDs are very common. Sometimes the cause isn?t known. But the known causes of LLD in children include, injury or infection that slows growth of one leg bone. Injury to the growth plate (a soft part of a long bone that allows the bone to grow). Growth plate injury can slow bone growth in that leg. Fracture to a leg bone that causes overgrowth of the bone as it heals. A congenital (present at birth) problem (one whole side of the child?s body may be larger than the other side). Conditions that affect muscles and nerves, such as polio.
Many people walk around with LLD?s of up to 2 cm. and not even know it. However, discrepancies above 2 cm. becomes more noticeable, and a slight limp is present. But even up to 3 cm. a small lift compensates very well, and many patients are quite happy with this arrangement. Beyond 3 cm. however, the limp is quite pronounced, and medical care is often sought at that point. Walking with a short leg gait is not only unsightly, but increases energy expenditure during ambulation. It could also put more stress on the long leg, and causes functional scoliosis. Where the discrepancy is more severe, walking becomes grotesque or virtually impossible.
Infants, children or adolescents suspected of having a limb-length condition should receive an evaluation at the first sign of difficulty in using their arms or legs. In many cases, signs are subtle and only noticeable in certain situations, such as when buying clothing or playing sports. Proper initial assessments by qualified pediatric orthopedic providers can reduce the likelihood of long-term complications and increase the likelihood that less invasive management will be effective. In most cases, very mild limb length discrepancies require no formal treatment at all.
Non Surgical Treatment
In an adult, we find that we can add a non compressive silicone heel lift to a shoe in increments of 3-4 mm maximum per week. Were we to give a patient with a 20 mm short leg, 20 mm of lift all at once, their entire body would rebel. The various compensations that the body has made, such as curvatures and shortening of muscles on the convex side of the curve, would make such a dramatic change not just noticeable, but painful. When we get close to balancing a patient by lifting a leg with heel inserts, then we perform another gait analysis and follow up xray. At that point, we can typically write them a final prescription to have their shoe modified. A heel lift is typically fine up to 7 mm. When it gets higher than that, the entire shoe must be modified. There are two reasons for this. The back of the shoe is generally too short to accommodate more than 7-8 mm inserted inside the shoes and a heel lift greater than 7 mm will lead to Achilles tendon shortening, which then creates it?s own panoply of problems.
functional leg length discrepancy treatment
Surgery to shorten the longer leg. This is less involved than lengthening the shorter leg. Shortening may be done in one of two ways. Closing the growth plate of the long leg 2-3 years before growth ends (around age 11-13), letting the short leg catch up. This procedure is called an epiphysiodesis. Taking some bone from the longer leg once growth is complete to even out leg lengths. Surgery to lengthen the shorter leg. This surgery is more involved than surgery to shorten a leg. During this surgery, cuts are made in the leg bone. An external metal frame and bar are attached to the leg bone. This frame and bar slowly pull on the leg bone, lengthening it. The frame and bar must be worn constantly for months to years. When the frame and bar are removed, a leg cast is required for several months. This surgery requires careful and continued follow-up with the surgeon to be sure that healing is going well.