What is Leg Length Discrepancy?
- There are generally two kinds of leg length discrepancies.
- What causes a leg length discrepancy?
- What are the symptoms of a leg length discrepancy?
- How is a leg length discrepancy diagnosed?
- How is a leg length discrepancy treated?
1. Structural discrepancy occurs when either the thigh (femur) or shin (tibia) bone in one leg is actually shorter than the corresponding bone in the other leg as a result of a condition that has either caused one bone to be shorter than normal or longer than normal.
2. Functional discrepancy occurs when the leg lengths are equal, by symmetry is altered somewhere above the leg, which in turn disrupts the symmetry of the legs. For example, developmental dislocation of the hip can cause a functional discrepancy. In DDH, the top of the leg bone (femur) that is not properly positioned in the hip socket may hang lower than the femur on the other side, giving the appearance and symptoms of a
leg length discrepancy.
The causes of a leg length discrepancy, even the most common ones, are numerous and varied. A discrepancy can result from an injury, such as in a fracture that damages the cells responsible for growth of the bone, while the corresponding bone on the other leg grows normally. Some fractures can also lead to overgrowth of bone during the healing process, resulting in a longer than normal bone. Overgrowth commonly occurs in young children with femoral fractures. Diseases of the bone, such as osteomyelitis, can injure a region in a bone, called the growth plate, where growth in length occurs, so that a discrepancy occurs gradually over time. Some children are born with legs that are of unequal length or bowed tibias that are accompanied with a leg length discrepancy.
Functional leg length discrepancy can also result from congenital (present at birth) problems, which alter alignment of the hips, such as coxa vara and developmental dislocation of the hip. Neuromuscular problems, such as cerebral palsy, which causes problems with alignment and posture, can also lead to a functional discrepancy. Bone tumors and treatments designed to irradicate them are related to leg length discrepancy. Tumors can invade the bone's growth plate like an infection and treatments, like chemotherapy, can also damage the plate.
The symptoms of a leg length discrepancy vary widely and are often related to the underlying problem causing the discrepancy and the alignment problems that result from it. Keep in mind that everyone experiences symptoms of this condition differently. Always consult a physician for a diagnosis.
The following are symptoms of a leg length discrepancy:
1. One leg is obviously shorter than the other (although this is not always obvious) problems with posture (i.e. shoulder may tilt toward shorter side) leading to compensatory or functional scoliosis.
2. Gait problems, such as limping, toe walking, or rotation of the leg.
3. A knee that's chronically hyper extended on the short side and flexed on the long side.
4. Pain in the back hip, knee, and/or ankle
Diagnostic procedures include a complete medical history of the patient and a physical examination by an orthopedic surgeon. The doctor will use both of these tools to determine the underlying cause of the problem.
During the physical exam, your doctor will probably take two measurements of your legs with a tape measure. One measurement, to determine the "real" length of the leg will be taken from the middle of the hip down to the ankle. The other, the "apparent" length, will be taken from the naval area. The discrepancy determined by these two measurements might be different if the "apparent" length is affected by hip position, suggesting a functional discrepancy.
The doctor may also ask you to stand with a block under the shorter leg to confirm the measurement estimate the amount of correction that feels best. The doctor will also want to confirm the measurement with the following diagnostic tests:
X-rays - a diagnostic test, which uses invisible electromagnetic energy, beams to produce images of internal tissues, bones, and organs onto film. This is used to obtain an accurate measurement of leg length discrepancy.
Computerized tomography scan (also called a CT or CAT scan) - a diagnostic imaging procedure that uses a combination of X-rays and computer technology to produce cross-sectional images (often called "slices"), both horizontally and vertically, of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CT scans are more detailed than general X-rays.
Specific treatment for leg length discrepancy will be determined by your orthopedic surgeon based on:
1. Your age, overall health, and medical history
2. The extent of the discrepancy
3. Your tolerance for specific medications, procedures, or therapies
4. Expectations for the course of the condition
5. Your opinion or preference
Your feelings about the treatment are extremely important. Some techniques used to equalize leg length are simple and safe, but others, especially lengthening procedures, are complex with high complication rates.
This is why we recommend using our shoe modification techniques. It is a non-invasive procedure which is cost effective and more importantly pain free.