Small or mild length leg discrepancies (LLD), i.e., below 3.0 cm, have been considered as enough to cause orthopaedic changes such as lumbar pain, stress fractures and osteoarthritis on lower limbs (LLLL) joints. In addition to the classification by its magnitude, discrepancies can also be categorized according to etiology, being structural when a difference is noted between bone structures' length or functional as a result of mechanical changes on the lower limb, and are found in 65% - 70% of the healthy population.
The causes of LLD may be divided into those that shorten a limb versus those that lengthen a limb, or they may be classified as affecting the length versus the rate of growth in a limb. For example, a fracture that heals poorly may shorten a leg slightly, but does not affect its growth rate. Radiation, on the other hand, can affect a leg's long-term ability to expand, but does not acutely affect its length. Causes that shorten the leg are more common than those that lengthen it and include congenital growth deficiencies (seen in hemiatrophy and skeletal dysplasias ), infections that infiltrate the epiphysis (e.g. osteomyelitis ), tumors, fractures that occur through the growth plate or have overriding ends, Legg-Calve-Perthes disease, slipped capital femoral epiphysis (SCFE), and radiation. Lengthening can result from unique conditions, such as hemihypertrophy , in which one or more structures on one side of the body become larger than the other side, vascular malformations or tumors (such as hemangioma ), which cause blood flow on one side to exceed that of the other, Wilm's tumor (of the kidney), septic arthritis, healed fractures, or orthopaedic surgery. Leg length discrepancy may arise from a problem in almost any portion of the femur or tibia. For example, fractures can occur at virtually all levels of the two bones. Fractures or other problems of the fibula do not lead to LLD, as long as the more central, weight-bearing tibia is unaffected. Because many cases of LLD are due to decreased rate of growth, the femoral or tibial epiphyses are commonly affected regions.
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.
On standing examination one iliac crest may be higher/lower than the other. However a physiotherapist, osteopath or chiropractor will examine the LLD in prone or supine position and measure it, confirming the diagnosis of structural (or functional) LLD. The LLD should be measured using bony fixed points. X-Ray should be taken in a standing position. The osteopath, physiotherapist or chiropractor will look at femoral head & acetabulum, knee joints, ankle joints.
Non Surgical Treatment
The treatment of LLD depends primarily on the diagnosed cause, the age of the patient, and the severity of the discrepancy. Non-operative treatment is usually the first step in management and, in many cases, LLD is mild or is predicted to lessen in the future, based on growth rate estimates in the two legs. In such cases, no treatment may be necessary or can be delayed until a later stage of physical maturity that allows for clearer prognostic approximation. For LLD of 2cm to 2.5cm, treatment may be as simple as insertion of a heel lift or other shoe insert that evens out leg lengths, so to speak. For more severe cases, heel lifts can affect patient comfort when walking, decrease ankle stability, and greatly increase the risk of sprains. For infants with congenital shortening of the limb, a prosthetic ? often a custom-fit splint made of polypropylene ? may be successful in treating more severe LLD without surgery. In many instances, however, a surgical operation is the best treatment for LLD.
functional leg length discrepancy 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.