Functional Leg Length Discrepancy Running

posted on 28 Apr 2015 18:36 by amie8day38

If one scans the literature it readily becomes obvious that leg length discrepancy/asymmetry is a common finding. This fact has been a very controversial topic within chiropractic, and diagnostic rationales have been built around this very common finding.

The object of this column is to consider some of the causes of this discrepancy that the profession may have ignored or not been aware of.Leg Length Discrepancy


Sometimes the cause of LLD is unknown, yet the pattern or combination of conditions is consistent with a certain abnormality. Examples include underdevelopment of the inner or outer side of the leg (hemimelias) or (partial) inhibition of growth of one side of the body of unknown cause (hemihypertrophy). These conditions are present at birth, but the limb length difference may be too small to be detected. As the child grows, the LLD increases and becomes more noticeable. In hemimelia, one of the two bones between the knee and the ankle (tibia or fibula) is abnormally short. There also may be associated foot or knee abnormalities. Hemihypertrophy or hemiatrophy are rare conditions in which there is a difference in length of both the arm and leg on only one side of the body. There may also be a difference between the two sides of the face. Sometimes no cause can be found. This type of limb length is called idiopathic. While there is a cause, it cannot be determined using currect diagnostic methods.


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.


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

Whether or not treatment should be pursued depends on the amount of discrepancy. In general, no treatment (other than a heel life, if desired) should be considered for discrepancies under two centimeters. If the discrepancy measures between two and five centimeters, one might consider a procedure to equalize leg length. Usually, this would involve closure of the growth plate on the long side, thereby allowing the short side to catch up; shortening the long leg; or possibly lengthening the short leg.

LLD Shoe Inserts

Surgical Treatment

Surgical lengthening of the shorter extremity (upper or lower) is another treatment option. The bone is lengthened by surgically applying an external fixator to the extremity in the operating room. The external fixator, a scaffold-like frame, is connected to the bone with wires, pins or both. A small crack is made in the bone and tension is created by the frame when it is "distracted" by the patient or family member who turns an affixed dial several times daily. The lengthening process begins approximately five to ten days after surgery. The bone may lengthen one millimeter per day, or approximately one inch per month. Lengthening may be slower in adults overall and in a bone that has been previously injured or undergone prior surgery. Bones in patients with potential blood vessel abnormalities (i.e., cigarette smokers) may also lengthen more slowly. The external fixator is worn until the bone is strong enough to support the patient safely, approximately three months per inch of lengthening. This may vary, however, due to factors such as age, health, smoking, participation in rehabilitation, etc. Risks of this procedure include infection at the site of wires and pins, stiffness of the adjacent joints and slight over or under correction of the bone?s length. Lengthening requires regular follow up visits to the physician?s office, meticulous hygiene of the pins and wires, diligent adjustment of the frame several times daily and rehabilitation as prescribed by your physician.