Epiphysiodesis is a surgical option designed to slow down the growth of the long leg over a period of months to years. It is only used in growing children. The operation involves a general anaesthetic. Small incisions are made around the knee near the growth plates of the thigh bone and the shin bone. The growth plates are prevented from growing by the use of small screws and plates (?8 - plates?). The screws are buried beneath the skin and are not visible. Stitches are buried beneath the skin and do not need to be removed. The child is normally in hospital for 2-3 days. The child can weight bear immediately and return back to normal activity within a few weeks. Long term follow up is required to monitor the effects of the surgery. The timing of the surgery is based on the amount of growth predicted for the child. Therefore, this procedure can under- and over-correct the difference in leg length. Occasionally the screws have to be removed to allow growth to continue. This procedure can be used on one half of the growth plate to correct deformity in a limb e.g. knock-knees or bow legs. This is known as hemiepiphysiodesis.
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.
Children whose limbs vary in length often experience difficulty using their arms or legs. They might have difficulty walking or using both arms to engage in everyday activities.
Asymmetry is a clue that a LLD is present. The center of gravity will shift to the short limb side and patients will try to compensate, displaying indications such as pelvic tilt, lumbar scoliosis, knee flexion, or unilateral foot pronation. Asking simple questions such as, "Do you favor one leg over the other?" or, "Do you find it uncomfortable to stand?" may also provide some valuable information. Performing a gait analysis will yield some clues as to how the patient compensates during ambulation. Using plantar pressure plates can indicate load pressure differences between the feet. It is helpful if the gait analysis can be video-recorded and played back in slow motion to catch the subtle aspects of movement.
Non Surgical Treatment
The key to treatment of LLD in a child is to predict what the discrepancy is at maturity. If it is predicted to be less than 2 cm., no treatment is needed. Limb length discrepancies of up to 2 or 2.5 cm. can be compensated very well with a lift in the shoe. Beyond 2.5 cm., it becomes increasingly difficult to compensate with a left in the insole. Building up the shoe becomes uncosmetic and cumbersome, and some other way of compensating for the discrepancy becomes necessary. The treatment of LLD is long-term treatment, and involves the physician and patient?s family working together as a team. The family needs to weigh the various options available. If leg lengthening is decided on, the family needs to understand the commitment necessary to see it through. The treatment takes 6 months to a year for completion, and complications can happen. But when it works, the results are gratifying.
Limb deformity or leg length problems can be treated by applying an external frame to the leg. The frame consists of metal rings which go round the limb. The rings are held onto the body by wires and metal pins which pass through the skin and are anchored into the bone. During this operation, the bone is divided. Gradual adjustment of the frame results in creation of a new bone allowing a limb to be lengthened. The procedure involves the child having an anaesthetic. The child is normally in hospital for one week. The child and family are encouraged to clean pin sites around the limb. The adjustments of the frame (distractions) are performed by the child and/or family. The child is normally encouraged to walk on the operated limb and to actively exercise the joints above and below the frame. The child is normally reviewed on a weekly basis in clinic to monitor the correction of the deformity. The frame normally remains in place for 3 months up to one year depending on the condition which is being treated. The frame is normally removed under a general anaesthetic at the end of treatment.