The Short Leg and Orthotic Support

Leg length inequality ("short leg") may ini­tially be suspected from a patient's clinical exam, spi­nal X-rays, or from recurrent subluxations. Begin with an accurate examination to de­termine the amount of dif­ference and influence this discrepancy has on the patient's spine and gait. Next, determine the source of the inequality, so the cor­rect treatment can be provided. Finally, determine, by evaluation, whether the treatment has sufficiently addressed the problem. Begin by examining the patient in the upright, weight bearing position. Check-ini> a patient on the treatment table intro­duces errors of position­ing which are difficult to exclude. Measurements of leg length discrep­ancy obtained in non-weight bearing posi­tions have been found to be unreliable.1 In the upright posture, these errors and confusions are no longer a fac­tor. Accurate clinical determinations are then possible.2 and effective chiropractic care can proceed. Since the lower extremi­ties provide foundational support for the pelvis during standing and walking, it is not surprising that they can have a pro­found effect on both pelvic and spinal alignment. Causes of Short Leg When one leg is shorter, there is often pelvic unleveling with a compensatory lumbar curve to the short side.1 Gait will be somewhat altered, in an attempt to make up for the difference. Eventually, specific degenerative changes will be seen in the spine' and hip joints/ A dif­ference in leg length (measured while standing) between 5-9 mm or over results in a higher incidence of low back pain." Athletes and those who spend a lot of time on their feet may develop chronic symptoms with just 3 mm of discrepancy.7 There are two possible causes of a short leg. and each needs different treat­ment. An anatomical short leg is caused by a difference in the length and/or size of the structures between the femur head and the ground. This is sometimes found af­ter a fracture or surgery, but is most often the result of asymmetrical growth. A functional short leg devel­ops secondary to a difference in the sup­porting structural alignment between the femur head and the ground. The most common cause is excessive pronation on one side, but knee valgus may also be a causative factor. Postural Examination Before beginning treatment of a short leg condition, perform a weight bearing postural examination of the pelvis and lower extremities. Position the patient in bare (or stocking) feet on an unyielding, level surface. Tell the patient to stand relaxed in a "normal upright posture."* Palpate the iliac crests1' and the lumbar spine, to determine if there is any pelvic unlevcling and a compensatory lateral curvature. If either is found, see whether the greater trochanters and knee joints are level, then evaluate the knee align­ment for valgus and the feet for asym­metrical hyperpronation. If there is evidence of a functional short leg, see if the pelvis and spinal imbalances can be temporarily corrected by having the patient roll onto the outsides of both feet. As you palpate the levels of the iliac crests and greater trochanters, ask the patient to relax and return to a normal stance. If the pelvis dips down or rotates forward on the side of greater foot prona-tion. this shows the effect of the foot im­balance on the pelvis and lumbar spine. A lack of significant asymmetry in the lower extremity alignment reveals an ana­tomical difference. Orthotic Treatment When evidence exists of a difference in lower extremity alignment (such as ex­cessive pronation). providing symmetri­cal support is the most effective treat­ment. This is accomplished by supply­ing custom-made, corrective orthotics for both feet. It is important to recognize the functional short leg, since providing a lift instead of an orthotic will likely perpetu­ate the associated sacroiliac subluxations.1" Only the standing pos­tural exam, with careful evaluation of lower ex­tremity alignment, per­mits this determination. If there is any doubt, the safest approach is to fit the patient initially with custom-made orthotics. If a leg length discrep­ancy persists after wear­ing the orthotics for sev- eral weeks and receiving chiropractic ad­justments, a heel lift can then be easily added to the orthotic for complete cor­rection. Heel Lifts When an anatomical difference in leg length affects the alignment of the pelvis and spine, chiropractic care should in­clude the recommendation of an appro­priate amount of lift under the heel. Since some asymmetry is tolerated by the body (most reliable studies find that about 5 mm is the limit)," an exact correction of the difference measured at the femur heads is not needed. The exception may be athletes (such as long distance run­ners), who spend many hours a day exer­cising and competing on their feet. For most patients, undercorrection (to within about 3 mm) is the best way to ensure a good response, while avoiding any nega­tive reactions. If the amount of lift needed exceeds 6 mm (the difference measured at the femur heads is more than 10 mm), the additional lift must be built onto the shoe, since a lift in excess of 6 mm will push the foot out of most shoes. This is done by adding half of the heel lift amount to the sole of the shoe, so the foot is not exces­sively plantar flexed during stance and gait. Conclusion Once a patient with a short leg has been properly examined, the source of the lower extremity shortening can be identi­fied, and effective treatment can be pro­vided. In many cases, orthotic support for foot pronation, knee rotation, or fe­mur angulation is needed. Those few patients with a true anatomical leg length discrepancy will need to be supplied with an appropriate lift. The additional time required to determine the source of the short leg will be repaid in more effective chiropractic care, and adjustments that last. Dr. John Danchik is the seventh in­ductee to the American Chiropractic As­sociation Sports Hall of Fame. He is the current chairperson oj the United States Olympic Committees Chiropractic Se­lection Program. He lectures extensively in the United States and abroad on cur­rent trends in sports chiropractic and rehabilitation. Dr. Danchik is associate editor of the Journal of the Neuro-musculoskeletal System and the Journal of Chiropractic Sports Injuries and Reha­bilitation. He has been in private prac­tice in Massachusetts for 24 years. You may reach Dr. Danchick at (617) 489-1220 or e-ma References I. Woerman AL. Binder-MacLeod SA. 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