One of the most frequently cited causes of biomechanical dysfunction is Leg Length Discrepancy (LLD).
This is a condition found in more than 33.4% of the population worldwide.
This alleged problem is widely discussed in medical literature and it is reassuring to know that the attitude of the medical profession towards the “shorter leg” has evolved over the years.
After neglecting this diagnosis for years, doctors started to prescribe heel wedges for every case of tilted pelvis, and routinely, their diagnosis rested on the observation of the posterosuperior iliac spine.
Although the immediate results were good, in the long term, they were disappointing.
Realizing that something was amiss, orthopedic surgeons will tell you that there is no need to correct a “shorter leg” under 1.5 to 2cm.
To think that dentists work on a precision of microns…One would hope, that precision in regards to LLD, is a must!
Leg Length Discrepancy Measurement
The first thing to know is that all classical measures are false: pubis to malleoli, greater trochanter to malleoli or iliac crest to malleoli.
An articulacy constrain, such as a slight valgus of one foot and a varus on the other foot, will cause one side of the pelvis to rotate forward relative to the opposite side.
To assume that a difference in leg length means that there is an actual difference in the length of the bones (femur and/or tibia) is most of the time a mistake. Most often what we are seeing is an apparent, or functional LLD. This is usually the result of disharmonic feet.
Leg Length Discrepancy and X-Rays
The orthogonal projection in X-Rays does not take into consideration the rotary pivot and the heights of the femurs. A simple articulary constraint (asymmetrical feet) can cause an X-Ray to show a difference of several millimeters.
What should be used?
The most accurate and reliable technique of measure is frontal teleradiography of a subject in the standing position. The angle between the feet should be of 30 degrees. The angle of the radiography tube should be of 15 degrees. And the patient should not be pressed against the plate.
To be accurate, it should be performed at a distance of 4 meters away from the body by measuring the diaphysis of each bone. If any doubts remain with respect to possible rotations. The measurements should be from the base of the greater trochanter to the inter-condylicus incisures.
Unfortunately, it is rarely done this way.
What are the Real Causes of Leg Length Discrepancy?
Leaving aside genetic and traumatic factors, the two legs should grow symmetrically.To believe that the two legs could grow at different rates would suggest that there is two different types of growth hormones.
Asymmetries observed in growth period, such as a diverging eye in a child, lead to asymmetries of pressure on the lower limbs, as described in Delpeche’s law: “ Any increased pressure on a limb will slow the growth of that limb” the opposite is also true, “any decrease in pressure will stimulate growth”.
As such, it is imperative that we start looking at convergence disorders in the younger population and addressing these postural asymmetries before the age of 16 1/2.
Symptoms of Leg Length Discrepancy
The health care system is spending a fortune on addressing purely symptomatic conditions such as the ones described below.
Here are some of the conditions (symptoms) linked to a Leg Length Discrepancy (cause).
- Meniscus ruptures (knee pain)
- Herniated disk DDD (lower back pain)
- Coxarthrosis (hip pain)
Posturology and Leg Length Discrepancy
There is no point in trying to assess a Leg Length Discrepancy without having corrected the adaptation of the feet and the asymmetry in eye tracking. Articulacy constraints and muscle imbalances will be found prior to doing so. Only then, can a professional tell you the accuracy of your short leg.
Posturology can allows a practitioner to correct a Leg Length Discrepancy (short leg) up to the millimeter close. Unless you know for certain that the length of one of your legs is different than the other (only Posturology can provide this answer) , you should be skeptical of shoe lifts as the first line of treatment for injuries.
The three take aways:
- Orthopedic surgeons will tell you that there is no need to correct a “shorter leg” under 1.5 to 2cm.
- All classical measure are false.
- Convergence disorders in children ( under 16 1/2 of age) lead Leg Length Discrepancy.
The Posturepro Team
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