Shortening techniques can be used after skeletal maturity to achieve leg length equality. Shortening can be done in the proximal femur using a blade plate or hip screw, in the mid-diaphysis of the femur using a closed intramedullary (IM) technique, or in the tibia. Shortening is an accurate technique and involves a much shorter convalescence than lengthening techniques. Quadriceps weakness may occur with femoral shortenings, especially if a mid-diaphyseal shortening of greater than 10% is done. If the femoral shortening is done proximally, no significant weakness should result. Tibial shortening can be done, but there may be a residual bulkiness to the leg, and risks of nonunion and compartment syndrome are higher. If a tibial shortening is done, shortening over an IM nail and prophylactic compartment release are recommended. We limit the use of shortenings to 4 to 5 cm leg length inequality in patients who are skeletally mature.
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.
The symptoms of limb deformity can range from a mild difference in the appearance of a leg or arm to major loss of function of the use of an extremity. For instance, you may notice that your child has a significant limp. If there is deformity in the extremity, the patient may develop arthritis as he or she gets older, especially if the lower extremities are involved. Patients often present due to the appearance of the extremity (it looks different from the other side).
A systematic and well organized approach should be used in the diagnosis of LLD to ensure all relevant factors are considered and no clues are overlooked which could explain the difference. To determine the asymmetry a patient should be evaluated whilst standing and walking. During the process special care should be used to note the extent of pelvic shift from side to side and deviation along the plane of the front or leading leg as well as the traverse deviation of the back leg and abnormal curvature of the spine. Dynamic gait analysis should be conducted during waling where observation of movement on the sagittal, frontal and transverse planes should be noted. Also observe head, neck and shoulder movements for any tilting.
Non Surgical Treatment
For minor limb length discrepancy in patients with no deformity, treatment may not be necessary. Because the risks may outweigh the benefits, surgical treatment to equalize leg lengths is usually not recommended if the difference is less than 1 inch. For these small differences, the physician may recommend a shoe lift. A lift fitted to the shoe can often improve walking and running, as well as relieve any back pain that may be caused by the limb length discrepancy. Shoe lifts are inexpensive and can be removed if they are not effective.
The type of surgery depends on the type of problem. Outpatient procedures may be used to alter the growth of the limb. This is often done through small incisions. If an outpatient procedure is done, your child can continue with most regular activities. Other times, surgery may be very involved and require the use of an external device that is attached to the limb with pins and wires. This device may be left on for months to correct the deformity or lengthen the leg. If this type of surgery is required, your child will be making weekly visits to Cincinnati Children's.