Leg lengthening/shortening

Alternative names:

bone lengthening; bone shortening; correction of unequal bone length; epiphyseal arrest; epiphysiodesis; femoral lengthening; femoral shortening

Definition:

A variety of surgical procedures to treat children with legs of unequal lengths, usually involving differences of 2 inches or more.

These procedures can:

• lengthen an abnormally short leg (bone lengthening or femoral lengthening)
• shorten an abnormally long leg (bone shortening or femoral shortening)
• limit growth of a normal leg to allow a short leg to grow to a matching length (epiphysiodesis or epiphyseal arrest)

Description:

BONE LENGTHENING
Lengthening an abnormally short leg may be recommended for children whose bones are still growing (skeletally immature). This is a series of treatments involving several surgical procedures, a lengthy convalescent period, considerable risks, but can add up to 6 inches in length.

While the child is deep asleep and pain-free (using general anesthesia), the surgeons carefully study the blood vessels and blood supply to the bone. An incision is made in the bone to be lengthened; usually the lower leg bone (tibia) or upper leg bone (femur). Metal pins or screws are inserted into and through the skin and bone above and below the bone incision and the skin incision is stitched closed. A metal device (such as an Iliazarov device) is attached to the screws in the bone and will be used later to gradually "crank" the cut bone apart, creating a space between the ends of the cut bone. The lengthening device is used very gradually, lengthening the bone in extremely small steps. Later, when the leg has reached the desired length (usually after several months), another surgical procedure will be done to place pieces of bone (bone graft) into the space between the ends of the lengthened bone. A metal plate with screws may be used at this time to stabilize the bone while the bone and bone graft heal.

Because the pins or screws are inserted through the skin into the bone, special care of the pin sites is important to prevent infection. And, because the blood vessels, muscles, and skin are stretched with each lengthening, careful and frequent checking of the skin color, temperature, and sensation of the foot and toes is necessary to prevent circulatory, muscular, or nerve damage.

BONE SHORTENING
Shortening a longer leg may be recommended for children whose bones are no longer growing (skeletal maturity). This is a technically complicated surgery, but can produce a very precise degree of correction.

While the child is deep asleep and pain-free (using general anesthesia), the surgeons carefully study the blood vessels and blood supply to the bone. An incision is made in the bone to be shortened; usually the lower leg bone (tibia) or upper leg bone (femur) and a section of bone is removed. The ends of the cut bone will be joined and a metal plate with screws is placed over the bone incision to hold it in place during healing.

Because the blood vessels, muscles, and skin are involved, careful and frequent checking of the skin color, temperature, and sensation of the foot and toes is necessary to prevent circulatory, muscular, or nerve damage.

BONE GROWTH RESTRICTION
Bone growth takes place at the growth plates (epiphyses) at each end of long bones. Restricting bone growth may be recommended for children whose bones are still growing and is used to restrict the growth of a longer bone to allow the shorter bone to continue to grow to match its length.

While the child is deep asleep and pain-free (using general anesthesia), the surgeons make an incision over the growth plate at the end of the bone in the longer leg. Placing a metal staple or piece of bone (bone graft) over the growth plate (epiphysiodesis, epiphyseal stapling, or epiphyseal arrest) will restrict further growth at that growth plate, allowing the shorter leg to continue to grow to match its length. Proper timing of this surgical treatment is an important factor to assure good results.

REMOVAL OF IMPLANTED METAL DEVICES
Metal pins, screws, staples, or plates are used to stabilize bone during healing. Most orthopedic surgeons prefer to plan to remove any large metal implants after several months to a year to reduce the potential for bone infection in the future. Removal of implanted metal devices requires another surgical procedure under general anesthesia.

Indications:

Surgical treatment may be recommended for severe unequal leg lengths caused by:

• poliomyelitis and cerebral palsy
• small, weak (atrophied) muscles or short, tight (spastic) muscles may cause deformities and prevent normal leg growth
• hip diseases such as Legg-Perthes disease
• previous injuries or bone fractures that may stimulate excessive bone growth
• abnormal spinal curvatures (scoliosis)
• birth defects (congenital deformities) of bones, joints, muscles, tendons, or ligaments