Limb length discrepancies of the lower extremity often cause disabling problems of the hips and lower back. It is also known as the short leg syndrome. This problem may affect as much as 75-80 percent of the population, resulting in pain in the lower back, pelvis or hip. Pain may also radiate down the thigh (sciatica nerve).

With even a slight half inch limb length discrepancy, a runner or walker or any person in general, can develop extreme symptoms and disability as the body tries to compensate for the difference. If you have severe hip pain, back pain or recurrent injuries on only one side of your body, there is a good possibility that one of your legs is shorter than the other.

There are two types of limb length discrepancies. The first type is the structural, which is a shortening in the length of the thigh bone or lower leg bone. The second type is a functional shortage, which is actually a position change in the bones during running or walking. The functional leg discrepancy is usually the result of one foot pronation (inward position) more than the other foot. Pronation causes the arch to flatten, resulting in an inward rotation of the leg and thigh. The pelvis will then drop downward, causing a functional shortage of the leg.

The majority of symptoms are usually found on the side of the longer limb because it is in contact with the ground longer and thus absorbs a greater amount of pressure and stress. The short limb also develops various symptoms such as shin splints, which are usually a result of the short leg overstraining while walking or running. A functional limb length discrepancy will respond well to biomechanical orthotic therapy. The lower extremity is examined and measured from the hip joint to the toes to find biomechanical imbalances as well as any leg length differences. Following that, a functional orthotic can be fabricated. The orthotic will realign the position and structure of the limb. The result will be an equal limb length and leveling of the pelvis.

If you find that you do have a short leg, but do not have any problems or pain, then do not try to treat the difference. The body has an ability to compensate for the problem and you could cause a problem by interfering with the adjustment.

Dr. Robert F. Weiss is a sports podiatrist specializing in foot and ankle surgery. He was a member of the Medical Advisory Committee of the 1984 and 1988 Olympic Marathon Trials. Dr. Weiss is a veteran of 35 Marathons & has a practice in Darien and resides in Westport. For info visit his Web site at www.therunning