Pronation is a turning outward of the foot at the ankle, which allows the foot to flatten. The pronation helps to absorb some of the compressive shock forces, torque conversion, adjustment to uneven ground contours, and maintenance of balance. It is necessary to have a certain amount of pronation to disseminate the energy of the foot-strike. If there is too little or too much pronation injuries may occur. When a foot and ankle pronates to a great degree, we call it over-pronation. Normally you can see the Achilles Tendon run straight down the leg into the heel. If the foot is over-pronated, the tendon will run straight down the leg, but when it lies on the heel it will twist outward. This makes the inner ankle bone much more prominent than the outer ankle bone.
There are many possible causes for overpronation, but researchers have not yet determined one underlying cause. Hintermann states, Compensatory overpronation may occur for anatomical reasons, such as a tibia vara of 10 degrees or more, forefoot varus, leg length discrepancy, ligamentous laxity, or because of muscular weakness or tightness in the gastrocnemius and soleus muscles. Pronation can be influenced by sources outside of the body as well. Shoes have been shown to significantly influence pronation. Hintermann states that the same person can have different amounts of pronation just by using different running shoes. It is easily possible that the maximal ankle joint eversion movement is 31 degrees for one and 12 degrees for another running shoe.
Common conditions seen with overpronation include heel pain or plantar fasciitis. Achilles tendonopathy. Hallus Valgus and/or bunions. Patellofemoral pain syndrome. Iliotibial band pain syndrome. Low back pain. Shin splints. Stress fractures in the foot or lower leg.
If you have flat feet or low arches, chances are you overpronate. Although not always the case, the lower your arches the greater the overpronate. Stand on a hard surface (in front of a mirror if you need to) and look at your feet, flat feet or low arches are easy to spot. If your feet look flatter than a pancake, have a look at your ankles and see if they seem collapsed or straight. If they are, you're overpronating.
Non Surgical Treatment
Fortunately, there are simple things you can do to cure and correct your overpronation issues. Certain exercises help. Pull your toes back using a rolled up towel. Roll your feet over a golf or tennis ball for a minute. And do calf raises by standing up and lifting up on your toes. These all help reposition the foot and strengthen the muscles and tendons necessary for proper support. Beyond that, simple adjustments to footwear will help immensely.
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%.