Limb-Length Discrepancy After Hip Arthroplasty

Overview

Approximately 75% of us present with one leg longer than the other. It?s staggering, literally, that so many people walk about with an imbalance. Yet to have one leg longer than the other doesn?t seem to create pain for everyone but for those that it does it brings pain in a myriad of dysfunction from TMJ, headaches, low back pain, IBS, bladder problems, sexual dysfunction, sacroiliac joint pain, pubis dysfunction, groin strain, gluteal dysfunction as well as the formation of trigger points.Leg Length Discrepancy

Causes

Some causes of leg length discrepancy (other than anatomical). Dysfunction of the hip joint itself leading to compensatory alterations by the joint and muscles that impact on the joint. Muscle mass itself, i.e., the vastus lateralis muscle, pushes the iliotibial band laterally, causing femoral compensations to maintain a line of progression during the gait cycle. This is often misdiagnosed as I-T band syndrome and subsequently treated incorrectly. The internal rotators of the lower limb are being chronically short or in a state of contracture. According to Cunningham's Manual of Practical Anatomy these are muscles whose insertion is lateral to the long axis of the femur. The external rotators of the hip joint are evidenced in the hip rotation test. The iliosacral joint displays joint fixations on the superior or inferior transverse, or the sagittal axes. This may result from many causes including joint, muscle, osseous or compensatory considerations. Short hamstring muscles, i.e., the long head of the biceps femoris muscle. In the closed kinetic chain an inability of the fibula to drop inferior will result in sacrotuberous ligament loading failure. The sacroiliac joint dysfunctions along its right or left oblique axis. Failure or incorrect loading of the Back Force Transmission System (the longitudinal-muscle-tendon-fascia sling and the oblique dorsal muscle-fascia-tendon sling). See the proceedings of the first and second Interdisciplinary World Congress on Low Back Pain. Sacral dysfunction (nutation or counternutation) on the respiratory axis. When we consider the above mentioned, and other causes, it should be obvious that unless we look at all of the causes of leg length discrepancy/asymmetry then we will most assuredly reach a diagnosis based on historical dogma or ritual rather than applying the rules of current differential diagnosis.

Symptoms

The effects of limb length discrepancy vary from patient to patient, depending on the cause and size of the difference. Differences of 3 1/2 percent to 4 percent of the total length of the leg (about 4 cm or 1 2/3 inches in an average adult) may cause noticeable abnormalities when walking. These differences may require the patient to exert more effort to walk. There is controversy about the effect of limb length discrepancy on back pain. Some studies show that people with a limb length discrepancy have a greater incidence of low back pain and an increased susceptibility to injuries. Other studies do not support this finding.

Diagnosis

There are several orthopedic tests that are used, but they are rudimentary and have some degree of error. Even using a tape measure with specific anatomic landmarks has its errors. Most leg length differences can be seen with a well trained eye, but I always recommend what is called a scanagram, or a x-ray bone length study (see picture above). This test will give a precise measurement in millimeters of the length difference.

Non Surgical Treatment

Heel lifts and sole lifts are simple ways Pedorthists can compensate for leg length deficiencies. These small modifications can make a tremendous difference to a person?s comfort, balance and mobility. Although people do not always know if they have LLD if you have any of the symptoms I have mentioned you should consult a Pedorthist as treating your condition early will reduce the development of serious problems later on.

LLD Shoe Inserts

height increase exercises

Surgical Treatment

In growing children, legs can be made equal or nearly equal in length with a relatively simple surgical procedure. This procedure slows down the growth of the longer leg at one or two growth sites. Your physician can tell you how much equalization can be gained by this procedure. The procedure is performed under X-ray control through very small incisions in the knee area. This procedure will not cause an immediate correction in length. Instead, the limb length discrepancy will gradually decrease as the opposite extremity continues to grow and "catch up." Timing of the procedure is critical. The goal is to reach equal leg length by the time growth normally ends. This is usually in the mid-to-late teenage years. Disadvantages of this option include the possibility of slight over-correction or under-correction of the limb length discrepancy. In addition, the patient's adult height will be less than if the shorter leg had been lengthened. Correction of significant limb length discrepancy by this method may make a patient's body look slightly disproportionate because of the shorter leg. In some cases the longer leg can be shortened, but a major shortening may weaken the muscles of the leg. In the thighbone (femur), a maximum of 3 inches can be shortened. In the shinbone, a maximum of 2 inches can be shortened.