Leg Length Discrepancy and Chronic Pain
by Robert Bonavolta, LMT, NMT

Leg length discrepancy, or as it has been alternatively termed, the short leg syndrome, is by far the most important postural asymmetry. Limb length discrepancy is simply defined as a condition where one leg is shorter than the other. If a substantial difference exists, disruptive effects on gait posture pain patterns can occur. Leg-length discrepancy can be divided into two groups:

1. Structural. True shortening of the skeleton from congenital, traumatic or
diseased origins.
2. Functional. Development from altered mechanics of the lower body, such as
foot hyperpronation/supination pelvic obliquity, muscle/joint imbalances,
poor trunk stabilization and deep fascial strain patterns.

Faulty feet and ankle structure profoundly affect leg length and pelvic positioning. The most common asymmetrical foot position is the pronated foot. Sensory receptors embedded on the bottom of the foot alert the brain to the slightest weight shift. Since the brain is always trying to maintain pelvic balance, when presented with a long left leg, it attempts to adapt to the altered weight shift by dropping the left medial arch (shortening the long leg) and supinating the right arch to lengthen the short leg.1 Left unchecked, excessive foot pronation will internally rotate the left lower extremity, causing excessive strain to the lateral meniscus and medial collateral knee ligaments. Conversely, excessive supination tends to externally rotate the leg and thigh, creating opposite knee, hip and pelvic distortions.

Biomechanical Relationship of Feet to Pelvis

Hip rotation is coupled with leg length discrepancy. In Figure 1, the femoral head on the long leg side “drives” the ilia upward and backward. Conversely, the ilium on the low femoral head side drops down (anteriorly rotates). The concurrent rotation of both ilia in opposite directions produces a left-on-left sacral torsion (Figure 2). This complex hip rotation coexisting with sacral rotation usually is described as pelvic obliquity. Sometimes there is a hip rotation due to other factors which simulate a longer leg and must be determined before treatments begin to eliminate pain.

Locomotion

For efficient locomotion, a symmetrical and well-aligned body is essential. When the three bones of the pelvis are distorted by limb length discrepancies, gravitational forces wreak havoc on weakened SI joint and accessory pelvic ligaments (sacrotuberous, iliolumbar and Iliosacral). These structures find themselves desperately struggling to maintain structural balance. Left untreated, a diverse array of symptoms appears as the short leg destabilizes the pelvis by unleveling the sacral base. Painful lumbar compensations often travel all the way up through the atlantooccipital (A-O) joint or C1,C2, as the spinal column is forced to rotate and side-bend to accommodate the uneven sacral base.

In the lower limbs, short leg compensations can be summarized as follows:
• Ankle instability due to foot supination on the short side;
• Knee hyperextension on the short side and the knee flexed on the long side;
• Externally rotated leg on the short side; and/or
• Circumduction of the long limb.

Trunk and Head Compensations

Compensatory (functional) scoliosis commonly is reflected as a low shoulder on the high ilium side, as seen in Figure 3. A short “C” curve is common in the cervical spine, due to a “stuck” occipitoatlantal joint unable to tilt the head on the neck to level the eyes with the horizon possibly causing migraine patterns, tinnitus, eye pain and TMJ dysfunctions. Elbow and hand positions can appear shorter on the short leg side, with the opposing arm swinging more on that side. Some authors suggest that there is a rotation of the pelvis toward the long leg side, possibly due to hyperpronation and medial leg rotation.2 These authors describe a typical gait when the short leg steps down and the long leg compensates by “vaulting.” It’s almost like stepping in a pothole with every step you take and causing a mini whiplash, if you will, 8000 times a day! Walking on the toes on the short side and flexing the knee of the long side seems to be a fairly consistent compensatory movement pattern. As the center of gravity unevenly shifts, the smooth sinusoidal motion of gait is disrupted. Thus, the cosmetic effect of walking also can contribute to the compensatory mechanism and eventual injury. For example, walking on the toes can lead to contracture of the Achilles and calf muscles, creating conditions such as Achilles tendinitis and plantar fascitis. Other functional scoliotic compensations include shortening of the quadratus lumborum on the long side, and a shortening of scalene, levator scapulae, sternocleidomastoid, and upper trapezius muscles on the contralateral side. This typical adaptive muscle imbalance pattern helps maintain erect head position with eyes level. The body always wants to be level and will do almost anything, including being in pain to maintain equilibrium. Regrettably, prolonged muscle shortening “crams” vertebral and rib articulations, compounding the problem. The spine’s neuronal pool overflows as subthreshold stimuli progress to full-blown efferent nerve discharge, triggering increased muscle guarding. Thus, a vicious pain/spasm/pain cycle, or reflex arcs, sinks its neurological tentacles deep into old intrinsic spinal groove muscles (rotatores, multifidus, intertransversarii and levator costalis), resulting in central nervous system overload, limbic system hyperactivity … and dis-STRESS and dis-EASE.

The presence of a limb length discrepancy usually is easily recognizable during gait by observing the following:
• Shoulder tilting to one side;
• Unequal arm swing;
• Pelvic tilt;
• Foot supinated on the short side and pronated on the long side;
• Ankle plantarflexed on the short side; and/or
• Knee flexed on the long side.

Note: During running, it has been suggested that limb length discrepancy makes no real difference, due to the fact that only one foot strikes the ground at any given time. However, Blustein and D'Amico’s extensive research finds that leg length discrepancy is the third most common cause of running injuries.3

Summary

The importance of limb length discrepancy cannot be ignored and often is the key feature in lower limb and back pathologies as well as headache patterns and TMJ dysfunction. Thus, the use of proper visual and anatomic landmark evaluations is paramount in distinguishing between a functional and a structural limb length discrepancy. Proper limb measurement is essential. Although presentations do differ from client to client, most of the previously discussed patterning theories will prove accurate. Integral parts of treating the condition are identification, comprehension of each individual’s compensatory adaptations and their relationship to resultant symptomatology. The study and practice of Neuromuscular Therapy seems to be the most powerful physical medicine to treat chronic pain disorders from injury as well as leg length discrepancies. Remember: The effectiveness of Neuromuscular Therapy lies in the efficiency of the therapist, the thoroughness of the exam and the precision of determining the muscles in dysfunction. If you believe that you may have a leg length issue please contact our offices to schedule a free postural exam through October (except Columbus weekend).

At the Montauk Wellness Center and Atlantic Corrective Therapy & Massage we have an extensive client education video lending library for anyone who is interested in learning more about how Neuromuscular Therapy can help you in your quest to be pain free. During October 2007 we are offering free postural analysis for new clients in both the Montauk office and our new East Hampton office! The exam should take no more than 30 minutes and will be by appointment only.

Robert Bonavolta is a licensed massage therapist specializing in Neuromuscular Therapy focusing on chronic pain management and sports injuries. He is also an AFAA certified personal trainer and a certified Spinning® instructor. For more information and to schedule an appointment call the Montauk Wellness Center and Atlantic Corrective Therapy and Massage at 631-668-0300 or visit the office at 6 South Elmwood Avenue along with Local Beauty with Maureen Jacob, LE, offering corrective skin care, facials, peels, waxing, spray tanning and massage as well as local arts and crafts and skin care products. And now also in East Hampton 9 N. Main St 631-764-3938. Visit us at www.montaukwellnesscenter.com

References:

1. Eric Dalton, PdD Short Leg Syndrome. Massage Today 2007
2. Donatelli R. The Biomechanics of the Foot
and Ankle. F A Davis Co., 2006; pp. 55-9.
3. Blake RL, Ferguson H. Limb length discrepancy. JAPMA, 1992; pp. 33-8.
4. Blustein SM, D’Amico JC. Limb length
discrepancy: identification, clinical significance
and management. JAMPA, 1985; pp. 200-6.