Upper Leg Bone
A: This is a great question, and quite a common finding for many people: having one leg shorter than the other. And as your second surgeon seemed to point out, the presence of one leg shorter than another and low back pain in the same person could be related. Most individuals have a small difference in their leg lengths. Because this is so common, if the difference between right and left is small enough, it does not typically contribute to lower back pain. This is usually the case for people if their leg length difference is less than a ¼ inch. (On a personal note, when I went to my chiropractor recently for a shoulder/neck issue, she mentioned that I had a slight leg length discrepancy that I had never known about. And it turns out I have occasional lower back and sacral pain!)When you get leg lengths that differ greater than 1/4 inch, that is when it can contribute to lower back pain. And if you have a leg length difference of greater than ½ inch, you are six times more likely to have an episode of lower back pain. That is pretty significant!
For those not familiar with Leg Length Discrepancies (LLD), I’d like to give a little more background. The two main causes of LLD are: 1) poor alignment of the pelvis and 2) having one leg that is structurally longer than the other. Other potential causes include an injury (such as a fracture), bone disease, bone tumors, congenital problems (present at birth) or neuromuscular problems, but these are much less common. Regardless of the reason, your body wants to be symmetrical and will do its best to compensate for the length difference. Certain other conditions can be present along with leg length discrepancy, such as scoliosis, lumbar herniated discs, pelvic torque, greater trochanteric bursitis, hip arthritis, piriformis syndrome, patellofemoral syndrome and foot pronation. I’ve written about a few of these other conditions elsewhere in our blog. But if you have one of these other diagnoses, you may want to ask your doctor to check you for a leg length discrepancy.
The signs and symptoms of LLD can include:
- one leg being obviously longer than the other (mine was not obvious to me!)
- affected posture, especially secondary scoliosis or one shoulder higher than other (and scoliosis could lead to secondary LLD)
- problems with gait
- pain in the lower back, but also hip, ankle or knee
Lower Leg Bones
As mentioned above, LLDs can be the result of legs actually being of different lengths or the pelvis being torqued and tipped. This leads to two ways of classifying LLD: a structural leg length discrepancy or a functional leg length discrepancy. A structural leg length discrepancy is a hereditary circumstance where one leg is simply longer than the other leg. This is determined if your pelvis and sacroiliac joints are symmetrical and the leg length is simply due to one leg truly being longer than the other, say via an X-ray. Functional leg length discrepancy is diagnosed when there is a torsion or pelvic rotation, commonly a sacroiliac (SI) joint dysfunction, which causes one leg to function as though it is longer or shorter than the other. In order to determine if a true structural discrepancy exists, a physical therapist must treat the pelvis and return it to a neutral position before measuring for the leg length discrepancy. Once the pelvis is symmetrical, if the leg length discrepancy goes away it is classified as functional. If it remains and has a measurable difference, it is a structural leg length discrepancy. So our questioner of the week may want to begin by finding out if she has a structural or functional LLD, before deciding how yoga can be applied.How does your western MD and Physical Therapist usually address leg length discrepancy? Structural leg length discrepancy can be treated with a heel lift in the shorter leg’s shoe. You want to let your physical therapist determine the height of the lift, since it is determined by how much lift is needed to restore proper biomechanics in the pelvis and lower back. I know of at least one student of mine who wears a thin-soled shoe on one foot during her yoga practice, as well as a heel lift in one shoe outside of yoga class. This seems to compensate and correct her imbalance and allows her to fully participate in all of her standing poses, especially the symmetrical ones such as Mountain pose (Tadasana), Powerful pose (Utkatasana) and Standing Forward Bend (Uttanasana). In rare instances, surgery may be recommended to either shorten or lengthen the limb. This is always accompanied by a course of physical therapy, which helps to stretch muscles and maintain joint flexibility, which is something yoga asana could compliment.
For a functional leg length discrepancy where the real issue is the tipping and torque of the pelvis, no heel lift is required. Instead, a physical therapist would use proper manual therapy techniques and specific therapeutic exercise to treat and normalize pelvic and lower extremity compensations. In yoga styles where alignment is a main focus of the poses (such Iyengar and Anusara), the asana practice could function to restore pelvic evenness. Once the pelvis is even, you should re-measure your legs. If they are pretty close to even, your leg length discrepancy was functional; if not, you could have an underlying structural leg length discrepancy that might still require a heel lift. I wish there were one or two poses I could recommend without knowing all this student’s particulars, but that is not possible without an more thorough history and physical exam. In general, a well-balanced yoga practice that includes reclining, seated, standing and some easy inverted poses could serve as a good starting point. But since low back pain is present, I’d recommend looking for a specialty class on yoga for back pain, where you are more likely to have a teacher experienced enough to give you some special guidance.
—Baxter
