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The “Long and Short” of Back Pain: Leg Length Discrepancy

The “Long and Short” of Back Pain: Leg Length Discrepancy

Bill Gallagher PT, CMT, CYT

The "Long and Short" of Back Pain: Leg Length Discrepancy

By Bill Gallagher, PT, CMT, CYT

Claudia’s hope for liberation from chronic back pain had begun to wane. Previous treatment by a physical therapist, two different chiropractors, an acupuncturist and a Rolfer, not to mention her consistent yoga practice over 10 years, had failed to give her any lasting relief. As I examined her, I became more and more confident that I could help her. It became clear that the previous five clinicians had failed to see the “eight hundred pound gorilla” driving Claudia’s pain. Her left leg was about 10mm longer than her right leg. Claudia had some of the “usual” findings for a client with low back pain, including weakness of the abdominals and thigh muscles and tightness in psoas, piriformis and plantar-flexors. These strength and range of motion issues were mild, and had been partially addressed by the physical therapist and one of the chiropractors. So when I looked for structural asymmetries, I found:

? Bunion left greater than right; ? Flat left foot, supinated right foot; ? Left knee valgus greater than right; ? Lacking 5 degrees extension left knee; ? Lacking 5 degrees hip abduction left; ? Left inominate posteriorly rotated, right anteriorly rotated; ? Left pelvic/iliac crest brim higher than right; ? Right on left sacral torsion; ? Mild roto-scoliosis concave left lumbar, concave right thoracic spine.

Four-Pronged Approach

I surmised that all of the above asymmetries were the body’s way of compensating for the leg length inequality, so I took a four-pronged approach. I put a 3mm lift in her right shoe and added 1mm per week. The final lift was 9mm. I stopped adding to the lift when the sacral base was almost level because I find this tends to work better than completely correcting the discrepancy. I used muscle energy technique to correct the rotated inominate, sacral torsion and soften the compensatory scoliosis. Claudia learned adaptations of these muscle energy techniques to allow her to continue to unwind these compensations between sessions. I worked with Claudia to modify her yoga practice by avoiding postures that bring the spine out of neutral while it is loaded (i.e., seated twist, triangle). I also instructed her to spend more time in the asymmetrical poses (i.e., pigeon, supine spinal twist) that help “unwind” her pelvic and spinal compensations for the leg-length-discrepancy. I taught Claudia three Tai Chi Chuan/Qigong exercises to improve her ability to maintain the lumbar spine in a relatively neutral position (especially in the horizontal plane) during functional activities. By the sixth session, Claudia reported only occasional, minor (1/10) pain for about 20 minutes in the morning when she awoke in a prone position. We had two more sessions together to complete the home exercise program training before discharge. Claudia recently contacted me and let me know that she had experienced nary an exacerbation over the three years since I had worked with her.

Leg-Length Inequality

Did the leg-length inequality cause Claudia’s pain? No, I think it is more complicated than that. Back pain is almost always caused by multiple stressors that combine to overwhelm the patient’s ability to adapt. So, if Claudia had minimal mental stress, the perfect amount of physical activity, ideal nutrition and optimal ergonomics in every aspect of her life, she might have been able to rise to the challenge of her structural asymmetry in her 30s as well as she had in her 20s. A significant leg-length inequality can be likened to a drain on adaptive potential. Adaptive potential is the ability to handle mental stress, environmental stress, trauma, too much or too little activity and poor nutrition. This concept of adaptive potential, initially developed by Hans Selye (general adaptation syndrome), bears a striking resemblance to the concept of Qi in Chinese medicine and Prana from Yoga/Ayurveda.

So when Claudia was 25 years old, she had no low back pain. It was only when her adaptive potential dipped below a critical level that she was unable to handle the compensatory demands of the leg-length inequality. Putting the lift into her shoe eliminated this subtle drain on her adaptive potential. I credit a colleague, the late Jeff Ellis, for getting me to pay very close attention to the possibility of a leg length discrepancy when evaluating a new patient. When I took his course, he told a story about a patient brought to his office by a PT who had taken several evaluation and manual therapy courses with him. The PT had been working with this particular patient for months and the patient was still experiencing significant pain. Jeff figured out in five minutes that the unaddressed issue was a 12 mm leg length inequality. The point of the story was to make sure we checked for this asymmetry with every patient. It is not a trivial task to figure out whether a given patient has a significant leg-length inequality. Inominate rotation, hip/knee/ankle contractures, subtalar asymmetry, and pelvic up-slips can all cause or compensate for (hide?) an apparent leg-length discrepancy. Here is how I evaluate for bony symmetry:

Standing

Is there a scoliosis? Does one arm hang closer to the body? Is the weight distribution asymmetrical? Compare pelvic brim height. If one side is higher, my suspicion is raised. Compare inominate position. Is the apparently long side in posterior rotation? If so, this asymmetry cannot be causing the apparent leg-length inequality, but rather is likely compensating for a bony asymmetry. Compare hip alignment. Is the “long” side kept externally rotated? This fits the pattern I see in a truly long leg. By externally rotating the hip in swing phase, the toes on the long leg are less likely to catch on floor surface irregularities. Compare knee alignment and range of motion. Does the “long” side have a larger valgus? If so, the hypothesis that the apparently long leg is in fact longer is strengthened. Compare foot posture. If the side that appears longer in “a” is pronated more than the side with the lower pelvic brim, my suspicion is strengthened. If the opposite is true, I am less suspicious of a true leg-length discrepancy. Is there a significantly asymmetrical bunion? If the apparently long leg has a larger bunion than the other leg, my suspicion is strengthened.

Supine

Have the patient lift the pelvis in hook-lying to allow it to assume a neutral rotation unless an inominate is stuck. Compare medial malleoli for symmetry. Compare pelvic brims for symmetry. If the short side is more cranial, I will do a long, gentle leg pull on the short side. If this does not correct the pelvic asymmetry and there are no contraindications, I’ll do an up-slip manipulation. If one inominate appears stuck in anterior or posterior rotation, would that position tend to cause or compensate for the apparent inequality? An inominate stuck in anterior rotation will lengthen the leg, so if this is found on the short side, I’m thinking that the leg is actually shorter. If the short side is stuck in posterior rotation, then it is likely that that apparent leg-length inequality is caused by the iliosacral asymmetry. Either way, I’ll treat the inominate dysfunction to see how it changes the relative position of the medial malleoli. Check for asymmetry in ankle, knee, hip and inominate range of motion. If asymmetries are found, would they tend to cause or compensate for the apparent inequality?

Sitting

Is the scoliosis better or worse than in standing? Check iliac crest height. Is the apparently long side higher? Could that inominate be structurally larger? Often the tibia, femur and inominate will be larger on the long side.

Interview

When you go shoe shopping, is one foot bigger than the other? Are your pants hemmed to the same length? I take all this information together with the complete history to make a decision on whether there is a significant asymmetry. If the answer is “yes” I need to decide how to intervene. If the patient is hemiparetic on the short side, I would be unlikely to use a lift. Likewise, if the patient is 100 years old, I will be relatively conservative with a lift by under-correcting. If the leg-length discrepancy is a by-product of a recent surgery like joint replacement, I will tend to correct the asymmetry immediately with a lift. The younger the patient, all else being equal, the more aggressive I will be in leveling the sacral base via a lift. For clients like Claudia, I start at 3mm and gradually increase the lift 1mm per week until the sacral base is nearly level and the compensations like scoliosis are minimized. By leveling the sacral base, the drain on adaptive potential is reduced by making it unnecessary for the body to compensate for this bony asymmetry. These compensations can perpetuate pain syndromes anywhere between the TMJ and the toes. Take a look and you may find that leg-length inequality may be a “missing link” in your evaluation and treatment.

Holistic Physical Therapist, Bill Gallagher is an expert in leg length inequality. He sees clients at his office on the upper West side and makes home visits to patients on the upper East side and upper West side of Manhattan (NYC)