Leg Length Discrepancy Gait Cycle

posted on 28 Apr 2015 23:27 by aberrantquagmir17
Overview

Leg length discrepancy (LLD) or Lower limb discrepancy is a condition of unequal lengths of the lower limbs. The discrepancy may be in the femur, or tibia, or both. In some conditions, the whole side is affected, including the upper limbs. However, it is the discrepancy of the lower limbs that causes problems with ambulation, and the focus of this discussion will be about lower limb discrepancy.Leg Length Discrepancy

Causes

Some children are born with absence or underdeveloped bones in the lower limbs e.g., congenital hemimelia. Others have a condition called hemihypertrophy that causes one side of the body to grow faster than the other. Sometimes, increased blood flow to one limb (as in a hemangioma or blood vessel tumor) stimulates growth to the limb. In other cases, injury or infection involving the epiphyseal plate (growth plate) of the femur or tibia inhibits or stops altogether the growth of the bone. Fractures healing in an overlapped position, even if the epiphyseal plate is not involved, can also cause limb length discrepancy. Neuromuscular problems like polio can also cause profound discrepancies, but thankfully, uncommon. Lastly, Wilms? tumor of the kidney in a child can cause hypertrophy of the lower limb on the same side. It is therefore important in a young child with hemihypertrophy to have an abdominal ultrasound exam done to rule out Wilms? tumor. It is important to distinguish true leg length discrepancy from apparent leg length discrepancy. Apparent discrepancy is due to an instability of the hip, that allows the proximal femur to migrate proximally, or due to an adduction or abduction contracture of the hip that causes pelvic obliquity, so that one hip is higher than the other. When the patient stands, it gives the impression of leg length discrepancy, when the problem is actually in the hip.

Symptoms

Often there are few or no symptoms prior to the age of 25-35. The most common symptom is chronic lower back pain, but also is frequently middle and upper back pain. Same-sided and repeated injury or pain to the hip, knee and/or ankle is also a hallmark of a long-standing untreated LLD. It is not uncommon to have buttock or radiating hip pain that is non-dermatomal (not from a disc) and tends to go away when lying down.

Diagnosis

The only way to decipher between anatomical and functional leg length inequalities (you can have both) is by a physical measurement and series of biomechanical tests. It is actually a simple process and gets to the true cause of some runner?s chronic foot, knee, hip and back pain. After the muscles are tested and the legs are measured it may be necessary to get a special X-ray that measures both of your thighs (Femurs) and legs (Tibias). The X-ray is read by a medical radiologist who provides a report of the actual difference down to the micrometer leaving zero room for error. Once the difference in leg length is known, the solution becomes clear.

Non Surgical Treatment

Treatment depends on the amount and cause of the leg length discrepancy as well as the age of your child. Typically, if the difference is less than 2 cm we don?t recommend immediate treatment. We may recommend that your child wear a heel lift in one shoe to make walking and running more comfortable. If the leg length discrepancy is more significant, your doctor may recommend surgery to shorten or lengthen a leg. The procedure used most often to shorten a leg is called epiphysiodesis.

LLD Shoe Inserts

Surgical Treatment

For discrepancies over five centimeters, more aggressive surgical procedures-specifically leg lengthening procedures-are typically required. The specifics of this operative procedure are beyond the scope of this informational page, but your child's physician will be able to discuss the details in reference to your child's specific problems when considered appropriate.