People with leg length discrepancy, when one leg is longer than the other, usually have a waddling-type gait where the hips seem to move up and down during walking as the body tries to compensate for the inequality. There are two types of leg length discrepancy. The first type of leg length discrepancy involves a structural defect, where one bone is longer or shorter than the corresponding bone of the other limb. This can occur within the femur (upper leg bone) or the tibia and fibular (lower leg bones). Functional leg length discrepancy results from altered mechanics due to a malalignment in the spine or lower extremity.
There are many causes of leg length discrepancy. Some include, A broken leg bone may lead to a leg length discrepancy if it heals in a shortened position. This is more likely if the bone was broken in many pieces. It also is more likely if skin and muscle tissue around the bone were severely injured and exposed, as in an open fracture. Broken bones in children sometimes grow faster for several years after healing, causing the injured bone to become longer. A break in a child's bone through the growth center near the end of the bone may cause slower growth, resulting in a shorter leg. Bone infections that occur in children while they are growing may cause a significant leg length discrepancy. This is especially true if the infection happens in infancy. Inflammation of joints during growth may cause unequal leg length. One example is juvenile arthritis. Bone diseases may cause leg length discrepancy, as well. Examples are, Neurofibromatosis, Multiple hereditary exostoses, Ollier disease. Other causes include inflammation (arthritis) and neurologic conditions. Sometimes the cause of leg length discrepancy is unknown, particularly in cases involving underdevelopment of the inner or outer side of the leg, or partial overgrowth of one side of the body. These conditions are usually present at birth, but the leg length difference may be too small to be detected. As the child grows, the leg length discrepancy increases and becomes more noticeable. In underdevelopment, one of the two bones between the knee and the ankle is abnormally short. There also may be related foot or knee problems. Hemihypertrophy (one side too big) or hemiatrophy (one side too small) are rare leg length discrepancy conditions. In these conditions, the arm and leg on one side of the body are either longer or shorter than the arm and leg on the other side of the body. There may also be a difference between the two sides of the face. Sometimes no cause can be found. This is known as an "idiopathic" difference.
LLD do not have any pain or discomfort directly associated with the difference of one leg over the other leg. However, LLD will place stress on joints throughout the skeletal structure of the body and create discomfort as a byproduct of the LLD. Just as it is normal for your feet to vary slightly in size, a mild difference in leg length is normal, too. A more pronounced LLD, however, can create abnormalities when walking or running and adversely affect healthy balance and posture. Symptoms include a slight limp. Walking can even become stressful, requiring more effort and energy. Sometimes knee pain, hip pain and lower back pain develop. Foot mechanics are also affected causing a variety of complications in the foot, not the least, over pronating, metatarsalgia, bunions, hammer toes, instep pain, posterior tibial tendonitis, and many more.
A qualified musculoskeletal expert will first take a medical history and conduct a physical exam. Other tests may include X-rays, MRI, or CT scan to diagnose the root cause.
Non Surgical Treatment
The way in which we would treat a LLD would depend on whether we have an anatomical or functional difference. To determine which one is causing the LLD you will need to get your legs measured. This is the easiest way to determine if it is anatomical or functional. With a functional LLD we must first determine the cause and treat the cause. Should the cause be one that is not correctable then we may need to treat the LLD as if it were an anatomical or may have to treat the opposite leg to improve one's gait. As for the anatomical LLD, we may start off with a heel lift only in the shoe and follow up to see if we will need to put the lift full sole on the bottom of the shoe. This is determined by the affects that a heel lift in one shoe may have on that knee. Should the LLD be more than 1/4 inch we usually recommend starting between 1/8 inch to 1/4 inch less than the actual amount and let the body adjust to the change and then raise up to the measured amount later.
functional leg length discrepancy treatment
Surgeries for LLD are designed to do one of three general things ? shorten the long leg, stop or slow the growth of the longer or more rapidly growing leg, or lengthen the short leg. Stopping the growth of the longer leg is the most commonly utilized of the three approaches and involves an operation known as an epiphysiodesis , in which the growth plate of either the lower femur or upper tibia is visualized in the operating room using fluoroscopy (a type of real-time radiographic imaging) and ablated , which involves drilling into the region several times, such that the tissue is no longer capable of bone growth. Because the epiphyseal growth capabilities cannot be restored following the surgery, proper timing is crucial. Usually the operation is planned for the last 2 to 3 years of growth and has excellent results, with children leaving the hospital within a few days with good mobility. However, it is only appropriate for LLD of under 5cm.