Examination and Treatment of the Short Leg
TECHNIQUE
John Danchik
DC, FICC, CCSP
The presence of a short leg may initially be suspected from a patient’s clinical exam, spinal X-rays, or from a history of recurrent subluxations.1 The first step is an accurate examination to determine the amount of difference and the influence this discrepancy has on the patient’s spine and gait.2 Next, the source of the inequality must be determined so that the correct treatment can be provided. Finally, the treatment must be evaluated to determine if it has sufficiently addressed the problem.
This process cannot be performed without examining the patient in the upright, weight-bearing position. Whenever a patient is checked on the treatment table, whether prone or supine, errors of positioning are introduced (and are very difficult to exclude). Measurements of leg length discrepancy obtained in non-weight-bearing positions have been found to be very unreliable.3 In the upright posture, these errors and confusions aie no longer a factor. Accurate clinical and radiographic determinations are then possible,4 and effective chiropractic care can proceed. Since the lower extremities provide the foundation and support for the pelvis during standing and walking, it is not surprising that they can have a profound effect on the alignment of the pelvis (and the spine, as well).
Effects and Causes
When one leg is shorter, there is often pelvic unleveling with a compensatory lumbar curve to the short side.3 Gait will be altered somewhat in an attempt to make up for the difference, and eventually, specific degenerative changes will be seen in the spine5 and hip joints.6 7 Studies have found that a difference in leg length (measured while standing) between 5 to 9 mm or more results in a higher incidence of low back pain.8 9 Athletes and those who spend a lot of time on their feet may develop chronic symptoms with just 3 mm of discrepancy. 10 There aie two possible causes of a short leg, and each cause needs different treatment. Therefore, a successful outcome is dependent upon determining whether a patient has an anatomical asymmetry or a functional imbalance.
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 aligmnent 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. Pelvic subluxations and/ or lumbar muscle imbalances cannot be the cause since these problems do not alter leg length while standing or walking.
Postural
Examination
The first step when treating a patient with a short leg is the clinical weight-bearing postural examination of the pelvis and lower extremities (Fig. 1). Start by positioning the patient in bare or stocking feet on an unyielding, level surface. Tell the patient to stand relaxed in a “normal
upright posture.”11 Now palpate the iliac crests and the lumbar spine to determine if there is any pelvic unleveling and a compensatory lateral curvature. If either of these is found, see if the greater trochanters and knee joints are level and then evaluate the knee alignment for valgus and the feet for asymmetrical hyperpronation. If there is evidence of a functional short leg, check to see if the pelvis and spinal imbalances can be temporarily corrected. This is done by asking the patient to 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, relaxed stance. If the pelvis dips down or rotates forward on the side of greater foot pronation, 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 the difference to be anatomical.
Radiographic Procedures
The only acceptable method for obtaining an exact measurement of leg length discrepancy is with properly positioned standing X-ray images.12 To do this, we must limit sources of projectional distortion and magnification distortion, while carefully controlling equipment alignment and patient positioning. This entails the use of either an AP lumbopelvis view taken at a distance of 72 or 80 in. (instead of 40 in.) or a tightly collimated spot view of the femur heads from 40 in. With both of these methods, the patient must be standing in bare feet on an unyielding, level surface. Body weight is borne equally through both legs, with the knees extended. Heels are placed directly under the femur heads (the “parallelogram” stance), which ensures accurate measurements even with lateral displacement of the pelvis. All X-ray equipment components must be installed level and square, especially the bucky. The film must be placed along the bottom of the cassette, and the cassette must rest squarely in the bucky. If all factors ai e controlled, then accurate measurements of true femur head heights can be obtained from the standing films, and the effect of any discrepancy on the spine and pelvis can be determined.
Orthotic Treatment
When there is evidence of a difference in lower extremity alignment (such as excessive pronation), the most effective treatment is to provide symmetrical support. This is accomplished by supplying custom-made collective orthotics for both feet. It is very important to recognize the functional short leg since providing a lift instead of an orthotic is likely to perpetuate the associated sacroiliac subluxations.13 There is no reliable information on the radiographs to make this differentiation; it is only the standing postural exam with careful evaluation of lower extremity alignment that permits this determination. If there is any doubt, the safest approach is to fit the patient with custom-made orthotics, initially. If there is a persisting leg length discrepancy after wearing the orthotics for several weeks and receiving chiropractic adjustments, a heel lift can then easily be 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 good studies find that about 5 mm is the limit),14 an exact correction of the difference measured at the femur heads is not needed. The exception to this may be athletes (such as longdistance 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 plantarflexed 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.
References
1. Knutson G. Incidence of foot rotation, pelvic crest unleveling, and supine leg length alignment asymmetry, and their relationship to self-reported back pain. J Manipulative Physiol Ther 2002, 24:el.
2. Perttunen JR, Anttila E, Socergard J, Merikanto J, Komi PV. Gait asymmetry in patients with limb length discrepancy. Scand J Med Sei Sports 2004.
3. Woerman AL, Binder-MacLeod SA. Leg length discrepancy assessment: Accuracy and precision in five clinical methods of evaluation. J Orthop Sports Phys Therap 1984; 5:230-238.
4. Friberg O et al. Accuracy and precision of clinical estimation of leg length inequality and lumbar scoliosis: Comparison of clinical and radiological measurements. IntDisabil Studies 1988; 10:49-53.
5. Friberg O. The statics of postural pelvic tilt scoliosis: A radiographic study of288 consecutive chronic LBPpatients. ClinBiomech 1987; 2:212-219.
6. Giles LGF, Taylor JR. Lumbar spine structural changes associated with leg length inequality. Spine 1982; 7(2): 159-162.
7. Friberg O. Clinical symptoms and biomechanics of lumbar spine and hip joint in leg length inequality. Spine 1983; 8:643-651.
8. Leg Length Discrepancy Linked To Lower Back Pain, April 10, 2013 in by E. Larry Grine, Virginia Spine Institute
9. Friberg O. The statics of postural pelvic tilt scoliosis: A radiographic study of288 consecutive chronic LBPpatients. ClinBiomech 1987; 2:212-219.
10. Subotnick SI. Limb length discrepancies of the lower extremity: The short leg syndrome. J Orthop Sports Phys Therap 1981; 3:11-16.
11. Bullock-Saxton J. Postural alignment in standing: A repeatability study. Austral J Phys Ther 1993; 39:25-29.
12. Friberg O. Accuracy and precision of clinical estimation of leg length inequality and lumbar scoliosis: comparison of clinical and radiological measurements. IntDisabil Studies 1988; 10:49-53.
13. Rothbart BA, Estabrook L. Excessive pronation: A major biomechanical determinant in the development of chondromalacia and pelvic lists. J Manip Physiol Therap 1988; 11:373-379.
14. Traveil JG, Simons DG. Myofascial Pain and Dysfunction: the Trigger Point Manual. Vol. 2. Baltimore: Williams & Wilkins, 1992: 55.
John Danchik, DC, CCSP, FICC, FACC is notable for his contributions to Sports Chiropractic. From 1985 to 2007 Dr. Danchik was the Chairman of the US Olympic Committee's Chiropractor Selection Committee which chose DCs to go to the Training Center in Colorado Springs. Dr. Danchik lectures frequently on current trends in sports chiropractic and rehabilitation and is currently a family practice and public health instructor at Tufts University. In his pre-Chiropractic career, Dr Danchikwas a professional baseball player as a pitcher for the Boston Red Sox.
