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Orthopaedic Surgeons Lift Patients' Legs to New Heights

Posted on: Wednesday, 22 March 2006, 12:00 CST

CHICAGO, March 22 /PRNewswire/ -- For a variety of reasons -- whether from previous injury, neurological conditions, bone infection or diseases, or congenital conditions -- a person's legs can grow to different lengths. Commonly referred to as leg-length discrepancy (LLD), this condition affects both adults and children. Orthopaedic experts gathered today to discuss recent advancements in limb lengthening and deformity correction techniques at the 73rd Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS) at McCormick Place.

"Minor discrepancies in lower extremity limb lengths -- considered 1-1/2 cm or less -- are actually extremely common," said John G. Birch, MD, FRCS(C), orthopaedic surgeon and assistant chief of staff at Texas Scottish Rite Hospital for Children in Dallas. "However, adults and children with more than 2 cm difference between legs may have an increased risk of wear and tear on the back, hip and knee."

While trauma is a common cause of LLD, many problems stem from muscle weakness, birth defects or other deformities. To handle LLD of 2 cm or more, a non-surgical option is to wear a build up, or lift, in the shoe to make the legs feel the same length while standing or walking. However, most patients prefer not to wear a visible lift. In children, the growth of the longer limb can sometimes be "slowed" through surgery. Another alternative is to surgically shorten the longer limb. The final option for correcting LLD is to lengthen the shorter limb. Compared to limb lengthening, limb shortening is a less complicated and less painful procedure, but there is a limit to how much the bone can shorten without causing permanent muscle weakness.

Limb lengthening is performed in the following instances: when the difference in limb length is too extreme to be handled by shortening; when a deformity and LLD need to be corrected simultaneously; or when a patient prefers this option. For the past several decades -- though considered extremely challenging -- limb lengthening procedures have been very successful.

According to William G. Mackenzie, MD, FRCS(C), chairman of the department of orthopaedics at Alfred I. duPont Hospital for Children in Wilmington, Del., "Although different types of bone fixation are used today, the underlying method of limb lengthening and realignment is virtually the same throughout the world." After applying an external fixator -- a device placed outside of the leg that holds the bone in position with pins and wires -- the bone is divided in a non-traumatic fashion to preserve the surrounding tissues and is gradually lengthened. As the bone lengthens, new bony tissue fills the gap.

"Most people don't realize that if you pull bone apart slowly, it will stretch and grow," said Dr. Mackenzie. "However, since limbs can be lengthened only 1 mm per day, this is a very gradual process that takes a considerable amount of time."

New Developments in Limb Lengthening

One innovative way to lengthen bones of the lower extremities uses the combination of an external fixator and a metal rod inserted into the canal of the bone. While very similar to lengthening performed with an external fixator, this procedure decreases the risk of bending or breaking occurring in the newly lengthened bone after the external fixator is removed. Additionally, the patient spends less time "in the frame" via the combined procedure. The main disadvantages, however, are the prolonged need for crutches or a walker and the possible risk of severe bone infection.

"Bone is not of normal strength once an apparatus is removed after lengthening. There is a 15-20 percent chance the bone can break," explained Dr. Birch. "Because of this, expandable rods are an attractive alternative."

Another method to gradually lengthen limbs involves a telescoping nail. In this approach, after inserting an expanding metal rod into the internal canal of the thigh or shin bone, the orthopaedic surgeon makes a small crack in the bone. During the next few weeks and months, the length of the nail increases, causing the surrounding bone to lengthen. The lengthening components of the nail are activated by leg movement. With this technique, there is nothing worn outside the extremity, which offers patients an aesthetic benefit.

The newest technique currently under development is a telescoping plate for gradual lengthening of the thighbone. Once the plate is attached to the surface of the bone, a small crack is made in the bone. Several days post-surgery, the bone is gradually lengthened by frequent adjustments made using a small wrench inserted through a tiny incision in the skin.

"We now have the ability to lengthen and straighten limbs at the same time," Dr. Mackenzie explained. "This and other advancements with external fixators, plates and rods have revolutionized the care of adults and children with shorter limbs or limb deformities."

An orthopaedic surgeon is a physician with extensive training in the diagnosis and non-surgical as well as surgical treatment of the musculoskeletal system, including bones, joints, ligaments, tendons, muscles and nerves.

With more than 29,000 members, the American Academy of Orthopaedic Surgeons ( http://www.aaos.org/ ) or ( http://www.orthoinfo.org/ ) is the premier not-for-profit organization that provides education programs for orthopaedic surgeons and allied health professionals, champions the interests of patients and advances the highest quality musculoskeletal health. Orthopaedic surgeons and the Academy are the authoritative sources of information for patients and the general public on musculoskeletal conditions, treatments and related issues. An advocate for improved patient care, the Academy is participating in the Bone and Joint Decade ( http://www.usbjd.org/ ) -- the global initiative in the years 2002-2011 -- to raise awareness of musculoskeletal health, stimulate research and improve people's quality of life. The Academy's Annual Meeting is being held March 22-26, 2006 at McCormick Place in Chicago.

American Academy of Orthopaedic Surgeons

CONTACT: Carlye Fallon, +1-847-384-4035, fallon@aaos.org , or KoryD'Angelo, +1-847-384-4034, dangelo@aaos.org , both of American Academy ofOrthopaedic Surgeons

Web site: http://www.aaos.org/http://www.orthoinfo.org/http://www.usbjd.org/

Source: PRNewswire

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