True Leg Length Discrepancy Measurement

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Overview

Surgeries to lengthen a leg are generally only performed when there is a difference in leg length of greater than four centimeters. These types of surgeries can be more difficult and have more complications, such as infections, delayed healing, dislocations, and high blood pressure. In a several step process, bone lengthening surgeries involve cutting a bone in two in order to allow new bone growth to occur. After the bone is cut, a special apparatus is worn with pins that will pull the bone apart at approximately one millimeter per day. This causes osteogenesis, or new bone growth, in between the cut bone segments. A cast or brace may be required for several months after surgery to allow the new bone growth to harden and provide extra support.Leg Length Discrepancy

Causes

A number of causes may lead to leg length discrepancy in children. Differences in leg length frequently follow fractures in the lower extremities in children due to over or under stimulation of the growth plates in the broken leg. Leg length discrepancy may also be caused by a congenital abnormality associated with a condition called hemihypertrophy. Or it may result from neuromuscular diseases such as polio and cerebral palsy. Many times, no cause can be identified. A small leg length discrepancy of a quarter of an inch or less is quite common in the general population and of no clinical significance. Larger leg length discrepancies become more significant. The long-term consequences of a short leg may include knee pain, back pain, and abnormal gait or limp.

Symptoms

The patient/athlete may present with an altered gait (such as limping) and/or scoliosis and/or low back pain. Lower extremity disorders are possibly associated with LLD, some of these are increased hip pain and degeneration (especially involving the long leg). Increased risk of: knee injury, ITB syndrome, pronation and plantar fascitis, asymmetrical strength in lower extremity. Increased disc or vertebral degeneration. Symptoms vary between patients, some patients may complain of just headaches.

Diagnosis

On standing examination one iliac crest may be higher/lower than the other. However a physiotherapist, osteopath or chiropractor will examine the LLD in prone or supine position and measure it, confirming the diagnosis of structural (or functional) LLD. The LLD should be measured using bony fixed points. X-Ray should be taken in a standing position. The osteopath, physiotherapist or chiropractor will look at femoral head & acetabulum, knee joints, ankle joints.

Non Surgical Treatment

Whether or not treatment should be pursued depends on the amount of discrepancy. In general, no treatment (other than a heel life, if desired) should be considered for discrepancies under two centimeters. If the discrepancy measures between two and five centimeters, one might consider a procedure to equalize leg length. Usually, this would involve closure of the growth plate on the long side, thereby allowing the short side to catch up; shortening the long leg; or possibly lengthening the short leg.

Leg Length Discrepancy

Surgical Treatment

Surgical options in leg length discrepancy treatment include procedures to lengthen the shorter leg, or shorten the longer leg. Your child's physician will choose the safest and most effective method based on the aforementioned factors. No matter the surgical procedure performed, physical therapy will be required after surgery in order to stretch muscles and help support the flexibility of the surrounding joints. Surgical shortening is safer than surgical lengthening and has fewer complications. Surgical procedures to shorten one leg include removing part of a bone, called a bone resection. They can also include epiphysiodesis or epiphyseal stapling, where the growth plate in a bone is tethered or stapled. This slows the rate of growth in the surgical leg.

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