Pronation is the normal movement the foot makes to absorb the impact from walking or running. It occurs once the heel strikes the ground and the foot disperses the impact, stretching and flattening the arch as the foot rolls inward. Supination is the opposite motion of pronation. The foot supinates, or rolls on its outer edge, to help with stability as we walk or run. A reasonable amount of pronation is necessary for the foot to function properly. However, when the foot arch remains flat and the foot rolls inward too much one may have excessive pronation or overpronation. This medical condition can result from continually straining the feet and wearing footwear that lacks sufficient foot arch support.
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.
Over-pronation is a condition where the arch flattens out which makes the feet roll inward while walking. This condition is also known as flat feet. It imposes extreme additional stresses on the plantar fascia, a fibrous band of tissue which connects the heel to the forefoot. Over-pronation makes walking a painful experience because of the additional strain on the calves, heel and/or back. Treatment for over-pronation involves the use of specially-made orthotics which offers arch support and medial rear foot posting as corrective measures.
Bunions, calluses and crooked toes may indicate alignment problems. So, it is important to ascertain the condition of a client’s toes. Check the big toe to determine if the first joint of the toe is swollen, has a callus or bunion, and/or looks as though it abducts (i.e., hallux valgus) rather than pointing straight ahead. Also, look to see if the lesser toes seem to “curl up” (i.e., the person has hammer or claw toes). This may be indicative of damage to, or inflexibility of the plantar fascia caused by excessive flattening of the foot.
Non Surgical Treatment
When you see the doctor, he or she will likely perform a complete examination of your feet and watch you walk. The doctor will need to take x-rays to determine the cause of your flat feet. In some cases, further imaging may be needed, especially if your symptoms are severe and sudden in nature. Once you are properly diagnosed, your doctor will create an appropriate treatment plan. There are several options to correct overpronation, such as orthotics. In many cases, overpronation can be treated with non-surgical methods and over-the-counter orthotics. In severe cases, however, custom-made orthotics may work better. Orthotics provide arch support and therefore prevent collapse of the arch with weight bearing. They are made of materials such as spongy rubber or hard plastic. Your doctor will also want to examine your footwear to ensure they fit properly and offer enough medial support. Extra support and stability can be achieved with footwear that has a firm heel counter. If you are experiencing pain, you should be able to use over-the-counter pain medications such as ibuprofen to relieve symptoms.
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%.