Your child has been diagnosed with a leg-length discrepancy. This means that your child?s legs are slightly different lengths, with one leg longer than the other. The difference in lengths can vary widely. The larger the difference in lengths, the more problems that can result as the child gets older. Because of this, your child may be referred to a pediatric orthopedist (doctor specializing in treating bone and joint problems in children) for evaluation and possible treatment.
The causes of LLD are many, including a previous injury, bone infection, bone diseases (dysplasias), inflammation (arthritis) and neurologic conditions. Previously broken bones may cause LLD by healing in a shortened position, especially if the bone was broken in many pieces (comminuted) or if skin and muscle tissue around the bone were severely injured and exposed (open fracture). Broken bones in children sometimes grow faster for several years after healing, causing the injured bone to become longer. Also, a break in a child?s bone through a growth center (located near the ends of the bone) may cause slower growth, resulting in a shorter extremity. Bone infections that occur in children while they are growing may cause a significant LLD, especially during infancy. Bone diseases may cause LLD, as well; examples are neurofibromatosis, multiple hereditary exostoses and Ollier disease. Inflammation of joints during growth may cause unequal extremity length. One example is juvenile rheumatoid arthritis. Osteoarthritis, the joint degeneration that occurs in adults, very rarely causes a significant LLD.
Patients with significant lower limb length discrepancies may walk with a limp, have the appearance of a curved spine (non-structural scoliosis), and experience back pain or fatigue. In addition, clothes may not fit right.
The doctor carefully examines the child. He or she checks to be sure the legs are actually different lengths. This is because problems with the hip (such as a loose joint) or back (scoliosis) can make the child appear to have one shorter leg, even though the legs are the same length. An X-ray of the child?s legs is taken. During the X-ray, a long ruler is put in the image so an accurate measurement of each leg bone can be taken. If an underlying cause of the discrepancy is suspected, tests are done to rule it out.
Non Surgical Treatment
Structural leg length discrepancy can be treated with a heel lift in the shorter leg?s shoe, if the leg length is greater than 5 mm. The use and size of the heel lift is determined by a physical therapist based on how much lift is needed to restore proper lumbopelvic biomechanics. In certain cases, surgical intervention may be needed to either shorten or lengthen the limb. An important component to any surgical procedure to correct leg length discrepancies is physical therapy. Physical therapy helps to stretch muscles and maintain joint flexibility, which is essential in the healing process. For a functional leg length discrepancy no heel lift is required, but proper manual therapy techniques and specific therapeutic exercise is needed to treat and normalize pelvic and lower extremity compensations. The number of treatments needed to hold the pelvis in a symmetrical position is different for each patient based on their presentation and biomechanical dysfunctions in their lower back, pelvis, hip, knee, and foot/ankle. If you have pain in your lower back or lower extremity and possibly a length discrepancy; the two symptoms could be related. A good place to start would be a physical therapy evaluation to determine whether you have a leg length discrepancy and if it could be contributing to your lower back pain, hip pain, knee pain, or leg pain.
what is a heel raise?
Lengthening is usually done by corticotomy and gradual distraction. This technique can result in lengthenings of 25% or more, but typically lengthening of 15%, or about 6 cm, is recommended. The limits of lengthening depend on patient tolerance, bony consolidation, maintenance of range of motion, and stability of the joints above and below the lengthened limb. Numerous fixation devices are available, such as the ring fixator with fine wires, monolateral fixator with half pins, or a hybrid frame. The choice of fixation device depends on the desired goal. A monolateral device is easier to apply and better tolerated by the patient. The disadvantages of monolateral fixation devices include the limitation of the degree of angular correction that can concurrently be obtained; the cantilever effect on the pins, which may result in angular deformity, especially when lengthening the femur in large patients; and the difficulty in making adjustments without placing new pins. Monolateral fixators appear to have a similar success rate as circular fixators, especially with more modest lengthenings (20%).