Normally, about 65% of upper body weight travels on down to the Big toe. Each Big toe ends up when we walk, as we step over the front of our feet. This bending up should be up to about 50-60 Degrees. You can gently push up this big Toe to bend upward at what is called the first metatarsal joint. This is the joint connecting the foot bone to the first part of the Big Toe. The medical term for the Big toe is the First Hallux. It is very prominent and larger than the other foot toes in the front of the foot.
Functional hallux limitus is the medical term for the restriction of bending up at the first metatarsal joint. This restriction prevents the normal distribution of force (one’s body weight ) from traveling down through the hips and down each leg through to each foot. The concept was originally developed by Dr. Dananberg in 1986. He determined that this Functional limitus impedes the normal transmission of force. Part of this force diverts itself outward into the other 4 toes. This abnormal sideways movement of the normal force of walking creates an abnormal walking motion. If this slight abnormality of motion remains over years, without any intervention, important damaging changes gradually occur.
We can fix this problem with some easy office manipulations. Sometimes we also need shoe inserts (orthotics) providing some compensation for better foot movement. In my office, we have cheaper ones than the custom-made ones. The orthotics were developed and marketed by Dr. Dananberg, costing about $150 when fitted here. I have used mine for many years for my own functional hallux limitus, for my poorly bending Big Toes. Each set lasts for about one year.
Vallaton determined in 2010 that the actual cause of functional hallux limitus is a restriction of movement of the posterior tibialis tendon that travels on the side of the foot, the same side as the Big Toe, This tendon has a sheath around it at the ankle level. Picture this sheath as a long straw covering the tendon at the heel. We consider this tendon and sheath as a combined pulley mechanism. The normal work of the posterior tibialis tendon is two-fold: as a support for the foot, and to produce the push back of the distal first metatarsal head situated at the first metatarsal joint. The tendon pulls on the bone in a combined downward and backward motion toward the heel. The damage to this tendon occurs when the tendon becomes stuck inside the sheath that surrounds the tendon. Then the straw interferes with the normal backwards movement of the tendon ( a little bit only, but up towards the knee) , There is now friction between the tendon’s outer surface and the inside surface of the surrounding sheath. which results in a decrease or complete lack of the normal pulling backward of the first metatarsal. This inhibition results in a diminished distance of retraction of the tendon back towards the heel and results in poor movement of the Big Toe, affecting the foot, and sometimes the knee above.
Simple treatments will improve the bending up movement at the Big Toe. My experience is that very few other doctors know these. The easiest is a gentle side-to-side manipulation at the heel that I do in the office that Dr. Vallaton developed. Immediately after this manipulation, the patient walks in the hall and feels the improvement. I have developed an added simple standing side-to-side exercise, to do twice a day. This exercise works very well to continue the improvement. You can easily learn this when you see me at your visit.