The Hidden Dangers of Walking

Michael E. Graham, DPM FACFAS

Walking has been described as one of the best forms of exercise. It is cheap and easy to do. You don't need any special equipment or training, just a pair of shoes. Walking is the second most common motion of our body, beside breathing. The average person takes about 15,000 to 20,000 steps a day. People who are overweight, diabetic, or suffer with high cholesterol and heart disease are told to walk. Walking increases the metabolism, which aids in the loss of weight which lowers the blood pressure and blood sugar. However, even though there are countless benefits of walking there are also many hidden dangers.

When our feet are in-alignment no problem, but, when our feet are even just slightly out-of-alignment, excessive motion will occur. This excessive motion multiplied 15,000 times a day over, say 15 to 20 years, results in a multitude of neuromuscloskeletal deformities. That is why by the time we reach middle age all of a sudden we develop problems to our feet, knees, hips, back, etc. Just like a rubber band, you can stretch it hundreds of times without a problem, but eventually, it will loose it's elasticity and snap.

Pronation is a normal motion of the foot and excessive pronation is termed hyperpronation. Hyperpronation occurs due to obliteration of the sinus tarsi. The sinus tarsi, a naturally occurring space, is formed by a space under ankle bone (talus) and a space on the upper portion of the heel bone (calcaneus). This space should always stay open. A deformity exists when there is partial to full obliteration of this space. The cause of the abnormal closure of this space is really not known but is most likely caused by underdevelopment of the talus. This is usually an inherited problem from a parent to the child and so on. The underdeveloped talus then moves excessively on the calcaneus.

The talus is a torque converter and is responsible for the transmission of the weight of the body to the heel and rest of the foot. To put things in perspective a 180 pound person has four to five times their body weight going through each foot. This means that with every step taken there up to 810 pounds of force traveling throughout the foot. When the foot is in-alignment the foot easily accepts those forces on the talus and transfers them back to the ground. However, with obliteration of the sinus tarsi and excessive motion/deviation of the talus those forces are abnormally transferred to other parts of the foot. These excessive forces will then lead to damage to the soft tissues of the foot and ankle, resulting in abnormal bone deviations.

Abnormal bone deviation leads to excessive joint motion. Excessive joint motion leads to more pulling and stretching of the soft tissue attachments on the bone, producing the formation of bone spurs. Excessive joint motion leads to inflammation of the joint. Chronic inflammation of the joint means that there are various cells present in the joint that will degenerate the cartilage of the joint. Disintegration of the cartilage is what most medical people call arthritis. This leads to further pain and anti-inflammatory medications are given. These pills only mask the symptoms, meanwhile the underlying excessive motion is still present, more damage occurs with every step taken. Many various medicines are also injected into the joint to decrease the inflammation or increase the lubrication in the joint space. These are also temporary measures. Finally, the joint will be so severely damaged that the motion is lost, almost as if it is trying to fuse on its own to stop the excessive motion. Surgeons will usually perform a partial or total joint replacement to bring motion back to the joint. Even with joint replacement procedures, the same underlying deformity is still present. So that the "new" joint is vulnerable to wear and tear and will have to be replaced with another implant, and so on.

Hyperpronation of the foot has been blamed for the majority of musculoskeletal disorders of the body. In a quick review, obliteration of the sinus tarsi makes the ankle bone turn down and in causing the ankle to also turn in and the foot will turn out. Turning in of the ankle then causes a twisting of the tibia (leg bone) on the femur (thigh bone). Twisting of the knee with every single step taken causes an over-stretching of the soft tissues of the knee leading to the majority of knee problems. The leg muscles have to work harder to lift up the foot with every step taken leading to cramping and overworking of the leg muscles. Turning in of the ankle then leads to the femur being pulled out of the hip joint. The excessive hip motion leads to arthritic hip problems, sciatica, etc. The tilting of the pelvis as well as obliteration of the sinus tarsi is what causes a "leg-length discrepancy". An unstable hip causes tilting of the pelvis which is connected to the spine. This leads to unnatural forces to the vertebrae and the cushion in-between the vertebrae. Excessive force placed on the disc will cause it to bulge on one side of the other. Ligaments are pulling abnormally on the vertebrae, bone spur formation begins and spinal stenosis is the end result along with "pinched" nerves. A curvature begins in the lower back possibly leading to further curvature up the back that can lead to one shoulder higher that the other. Having a "tilted" shoulder leads to abnormal soft tissue strain, formation of bone spurs and the spurs cause further damage to the soft tissue resulting in rotator cuff problems. Tilted shoulders lead to excessive strain on the neck and can cause vertebral problems there resulting in excessive muscle strain. Just like the lower back, the very strong muscles along the spine try to keep the neck and back in-alignment, however they have to work extra hard to realign the spine an eventually cramp. Many headaches are caused by the strain on the neck muscles. A tilted neck leads to a tilted head. When the head is not straight this will then place abnormal forces on the mandible. One side of the mandible becomes displaced and the muscles of the mandible will tighten and cause symptoms otherwise know as TMJ syndrome.

This deformity of abnormal obliteration of the sinus tarsi is present at birth. As with many other disease processes, there are secondary symptoms that usually give more pain than the underlying problem itself. Even though the obliteration is occurring with every step pain is rarely present to this part of the body. The pain occurs at so many other places, treatment is usually focused at the area of symptoms. Say there is lower back pain, there are so many different products and modalities to aid in the relief of this pain. However, since no attention is paid to the obliteration of the sinus tarsi, there will be a recurrence of the deformity.

People who have the normal mechanics to their feet don't suffer when they walk and just take it for granted. They have a higher metabolism and therefore are overall much healthier, that is, less likely to suffer with heart disease, diabetes, etc. If there are normal mechanics to the feet the muscles are more efficient and therefore these people are more athletic. People with out-of-aligned feet have a lower metabolism, more likely to suffer with the ill-effects of heart disease, obesity, diabetes, etc. Their muscles have to work a lot harder and walking is more strenuous. The leg muscles work four to five times harder and walking a mile results in the leg muscles walking four to five miles.

What are the treatment option for people who have out-of-alignment? The most common form of treatment is a "corrective" arch support. The purpose of these is to try to prevent the "collapse" of the arch. But as we have previously learned, the problem is that the sinus tarsi is collapsing. An arch support works on the bottom of the foot and cannot prevent of the closure of the sinus tarsi. There are many other problems with arch supports. Almost any thing can be put into the shoe and some relief will be felt. Usually, this is short term and before we know it the pain is back, because the sinus tarsi is still obliterating. When we are prescribed corrective eye lenses we immediately can tell if that is the right lens because we can see clearly again. Arch supports only are effective if we can wear them in our shoes. There are many style of shoes or different activities when the arch supports cannot be worn. Certain conditions exist when the arch supports that are pushing up into our foot would actually cause more pain. I think you can see that arch supports for a large percentage of people are not the most effective means of treatment.

If arch supports where ineffective in treating the excessive foot motion the next option would be rearfoot reconstructive surgery. Usually, this was just too aggressive a solution for the deformity. There are many potential complications in performing this procedure, it has a long recovery, and the results are unpredictable. This modality is usually reserved for very severe foot deformities.

There now exists a better alternative. The problem is the abnormal closure of the sinus tarsi, when a structure closes abnormally a stent is usually placed in that space to keep it open. Well, we have a sinus tarsi stent that can be placed within the sinus. It takes the negative space of the sinus tarsi and turned into a positive space. The stent prevents the abnormal motion while the normal motion of the talus on the calcaneus is restored. The stent can be place in patients from three years and older. The oldest patient known who had the placement of the stent is 91 years old. The placement of the stent takes about five minutes. Patients are back into semi-normal shoes within three to four days after surgery. The procedure to insert the stent is called subtalar arthroeresis and is completely reversible. The stents are usually composed of medical grade titanium and will last a life time.

If this deformity of abnormal obliteration is diagnosed early enough and a sinus tarsi stent can be inserted there will less likely be a chance for deformity to the rest of the body. Diagnosis is usually made by a specialist of the foot and ankle. Clinical and radiographic findings as well as a gait analysis is performed. There are even new radiographic techniques that are available to show the actual open sinus tarsi with no weight on the foot to closure of the sinus with weight placed on the foot. However, if the partial to full obliteration is caught too late it is possible that there is irreversible damage that has occurred to the rest of the body. Sometimes there is so much of a deformity of the talus on the calcaneus that a sinus tarsi implant cannot be used and more aggressive rearfoot surgery would be needed to realign the foot and the rest of the body.

Even though walking is the best form of exercise for the average person, there are many hidden dangers. If the feet are out-of-alignment, repetitive damage is caused to the neuromusculoskeletal system that can further lead to obesity, heart disease, diabetes, depression, etc. Abnormal closure of the sinus tarsi is responsible to the misalignment of the feet and the rest of the body. There are many different treatment options available to try and re-align the foot. Just like we have the tires balanced on our car before we drive, we need to make sure our feet are in good alignment. When our feet are aligned, then we are able to walk to increase our metabolism, lower our weight, decrease our blood pressure, lower our blood sugar, and lead a healthier life.

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