A walk in the park on a lovely spring day sounds delightful. But for some, it's hard work. A person whose legs are unequal in length expends a lot more energy than average just to take one step. That usually means increased fatigue, which can put quite a damper on the outing.

    LLD, or limb length discrepancy, is a condition in which there is a significant difference in the length of a person's legs or arms. It can be the result of a birth defect, disease, trauma to the limb, tumor or infection in the limb. An inequality of the legs is more common and usually more problematic than that of the arms. A limp, lower back pain, scoliosis, degenerative arthritis and foot calluses are all associated with the condition. It can also affect a child's self esteem, particularly if he or she is taunted by peers.

    The good news is that in most cases LLD can be corrected. Sanjeev Sabharwal, MD, FRCFC, chief of pediatric orthopedics at UMDNJ - New Jersey Medical School, says lengthening a limb or straightening a deformed one is a long process that requires a total commitment from the patient, his or her family and the surgical team. But the results are usually quite dramatic. He is one of the few physicians in the area specializing in the repair of LLD and deformed limbs in children and young adults.

    The process used is called distraction histogenesis or the Ilizarov method, which is named for the pioneering work done in the early '60s by the Russian physician. There are three phases to the treatment. First, through a small incision, the bone is cut so it can be lengthened. It is done very carefully so the periosteum, or bone covering, is preserved, since it plays a major role in forming new bone. The surgeon then places a device, known as an external fixator, around the leg. It is comprised of lightweight carbon rings or a carbon bar that is attached to the bone, through the leg, by wires and/or screws. The wires are placed under a predetermined amount of tension. The fixator will be used to slowly pull the bone apart.

    About five to 10 days after surgery, the second phase, known as distraction, begins. Each day the patient or a family member turns a small wheel on the fixator a total of 1 millimeter. It is usually done in four installments, once at each meal and again at bedtime. The turn results in a space forming between the two ends of the bone. New bone forms within the space. Sabharwal says it takes about one month to gain a centimeter of length.

    When the desired length or angle of the bone is achieved, the consolidation phase begins. During this time, which is usually twice that of the lengthening time, the new bone and tissue become solid. The fixator is then removed under general anesthesia, and the patient is fitted with a temporary cast or brace. This is to ensure that the new bone does not get broken. Ongoing physical therapy to maintain joint mobility is essential, as is follow-up care. Sabharwal says if a patient is negligent about his after-care, temporary or even permanent loss of function may result.

     Once the fixator is in place, Sabharwal says, the procedure is essentially painless. In fact, if a patient experiences pain, it may indicate one or more of several problems: the lengthening is being done too quickly; there is an infection around a pin; there is excessive stretching of tendons and nerves; or the joints have become stiff. Going to a highly trained specialist who knows the intricacies of the procedure, however, greatly minimizes the risks.

    Besides his clinical work, Sabharwal is researching methods of improving the procedure. He is currently looking at whether releasing some of the tendons that go across the growth plate helps preserve natural growth during lengthening.

    Although limb lengthening is anything but a simple procedure, it's helping many have a truly wonderful walk in the park.