Overpronation Of The Feet

Overview

Pronation, in anatomical terms, means to rotate, and it applies to any rotational movement of a bone. Pronation in the feet involves an inward rolling of the foot throughout the gait which helps with the transfer of force. Normally the foot will move from the heel to the toes with only a small degree of pronation, with a slight inward roll from the outside of the heel to the inside of the foot which helps to support the body weight. Normal pronation involves the rolling of the foot to approximately 15 degrees. If you have normal foot arches, you are likely to be a neutral runner and will most likely pronate normally.Over-Pronation

Causes

During our development, the muscles, ligaments, and other soft tissue structures that hold our bones together at the joints become looser than normal. When the bones are not held tightly in place, the joints are not aligned properly, and the foot gradually turns outward at the ankle, causing the inner ankle bone to appear more prominent. The foot moves in this direction because it is the path of least resistance. It is more difficult for the foot to move in the opposite direction (this is called supination). As we develop, the muscles and ligaments accommodate to this abnormal alignment. By the time growth is complete, the pronated foot is: abnormally flexible, flat, and its outer border appears raised so that as you step down you do not come down equally across the entire foot; instead, you come down mostly on the inner border of the foot. Normal aging will produce further laxity of our muscles that causes the pronation to become gradually worse.

Symptoms

Overpronation causes alterations in proper muscle recruitment patterns leading to tightness in the outside of the ankle (lateral gastrocnemius, soleus, and peroneals). This tightness can lead to weakness in the opposing muscles such as the medial gastrocnemius, anterior tibialis, and posterior tibialis. If these muscles are weak, they will not be able to keep the knee in proper alignment, causing the valgus position. All this tightness and weakness can cause pain within the ankle, calf, and knee region. And it can send imbalance and pain all the way up to the upper back, if deep core strength is lacking and can't hold the pelvis in neutral.

Diagnosis

Firstly, look at your feet in standing, have you got a clear arch on the inside of the foot? If there is not an arch and the innermost part of the sole touches the floor, then your feet are over-pronated. Secondly, look at your running shoes. If they are worn on the inside of the sole in particular, then pronation may be a problem for you. Thirdly, try the wet foot test. Wet your feet and walk along a section of paving and look at the footprints you leave. A normal foot will leave a print of the heel, connected to the forefoot by a strip approximately half the width of the foot on the outside of the sole. If you?re feet are pronated there may be little distinction between the rear and forefoot, shown opposite. The best way to determine if you over pronate is to visit a podiatrist or similar who can do a full gait analysis on a treadmill or using forceplates measuring exactly the forces and angles of the foot whilst running. It is not only the amount of over pronation which is important but the timing of it during the gait cycle as well that needs to be assessed.Over-Pronation

Non Surgical Treatment

Anti-Pronation Insoles provide a unique foot support system that aligns the lower body. The major cause of foot and leg pain is over pronation (rolling over of the feet) which causes excessive pressure on the muscles, ligaments and bones of the lower body. Running insoles treat the underlying cause of over pronation and prevent future occurrences of the associated foot or leg condition. A project conducted at the NIKE Sport Research Laboratory studied the effects of orthotics on rear foot movement in running. Nine well-trained runners who wore orthotics were chosen as subjects. The results of the study indicated that orthotics reduced rear foot movement by roughly one degree or approximately nine percent of the amount found in runners not using orthotics. The average reduction of the maximum velocity of pronation was fifteen percent. Thus this study indicates that orthotics and insoles control over pronation which will treat and prevent many sporting injuries.

Surgical Treatment

Hyperpronation can only be properly corrected by internally stabilizing the ankle bone on the hindfoot bones. Several options are available. Extra-Osseous TaloTarsal Stabilization (EOTTS) There are two types of EOTTS procedures. Both are minimally invasive with no cutting or screwing into bone, and therefore have relatively short recovery times. Both are fully reversible should complications arise, such as intolerance to the correction or prolonged pain. However, the risks/benefits and potential candidates vary. Subtalar Arthroereisis. An implant is pushed into the foot to block the excessive motion of the ankle bone. Generally only used in pediatric patients and in combination with other procedures, such as tendon lengthening. Reported removal rates vary from 38% - 100%, depending on manufacturer. HyProCure Implant. A stent is placed into a naturally occurring space between the ankle bone and the heel bone/midfoot bone. The stent realigns the surfaces of the bones, allowing normal joint function. Generally tolerated in both pediatric and adult patients, with or without adjunct soft tissue procedures. Reported removal rates, published in scientific journals vary from 1%-6%.

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