Dysmetria is a frequent reason for consulting the physician. With dysmetria I mean simply that one leg is longer than the other. There are many causes that can cause it, such as birth defects, developmental problems or traumatic injuries with fractures in the bones of the legs, to give some examples. I will talk about the dysmetria in general but especially focusing on back problems like scoliosis that influence the length of the legs.
Speaking of dysmetria in general is not the most appropriate because the treatment that should be performed does not depend on the difference in leg length itself. Rather it is necessary to treat the problem that is causing the dysmetry or to solve the problem that the own dismetria causes. That is, we would have to talk about many different injuries and diseases to give all the solutions.
Measuring leg length is an important step in calling things by name. It is not the same to have a real dysmetry than to have the sensation that we have one leg longer than the other. This perception we can have for example after an injury where we have been limping and has changed our outline of the march. I am going to tell you a case that I lived close to a patient who consulted for dysmetria. Suddenly, he had begun to notice that one leg was longer and he found it very uncomfortable to walk. To shorten the story, after evaluating that it was not a real dysmetry, it was possible to see that it was due to a very stressful period of the life of this person who had somatized in this way. He passed the stress and forgot his legs.
In general, without entering into the particular circumstances of each case, it is accepted that a dismetry of less than two centimeters is tolerable without correction. This means that if the difference in measurement of both legs is less than 2 cm, a treatment is not necessary. This is not always going to be the best, it depends on each case but it is good to keep it in mind. Another thing to keep in mind is that no one has both legs alike.
How do we measure the length of the legs?
There are two basic ways to have a length measurement of the legs.
– Using a tape measure, we measured the distance between two anatomical references, usually the anterosuperior iliac spine and the internal malleolus. We took the measurement on both legs and compared. When measuring this way you have to be very rigorous to minimize the margin of error that will always exist when using this method. Experience is long overdue.
– The second way is with an x-ray of both legs while we are standing. The measurements taken on an X-ray are more accurate than on the body because the references are clear. This does not mean that there is no margin for error, but probably the greatest risk of error occurs when performing the X-ray. A misplacement could give false results.
Scoliosis in scoliosis
The curve that forms the vertebrae often affects the position of the pelvis. If the pelvis is rotated and tilted, two things can happen. On the one hand, there may be dysmetria that is worsening the scoliosis curve, but on the other hand, it may seem that there is a dysmetria but it is not real. In the consultation many times what we do is to raise test scores and assess how scoliosis and anatomical references are modified as the axis of the back. In these cases the dysmetria should not be corrected only because we have measured a difference in length. It is very important to take into account all the data because we can harm with an incorrect prescription.
In short, it perishes very easy, if I have one leg longer than the other I put a raise for the difference and I equal them. Unfortunately it is not that simple. If we do this we are bound to fail and possibly cause more problems than we intend to solve. No two cases are the same and the previous situation, the type of injury or deformity and the functional situation to be corrected must be taken into account. I am going to set an example so that it is understood. Before all children who had flat feet were put on insoles. To solve or to prevent what? Today it is known that that does not make sense. Templates should be used when preventing a potential risk or solving a problem that is having repercussions on the person. Use to use, I do not recommend it.