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.
Pronation can occur as an overuse syndrome in active runners, where a great deal of stress is placed on ligaments and tendons that support the medial column. Obesity is another predictor for pronation and deterioration of the medial ligaments and posterior tibial tendon due to excessive stress on these tissues. Acute Trauma can also lead to over-pronation when ligaments are torn or tendon is ruptured. Once again this can lead to a collapse of the medial column. Arthritic conditions involving the knee joint when the joint is in varus (inner collapse) posture, this places the center of gravity over the ankle joint rather than the foot causing undue pressure on the inner ankle.
In addition to problems overpronation causes in the feet, it can also create issues in the calf muscles and lower legs. The calf muscles, which attach to the heel via the Achilles tendon, can become twisted and irritated as a result of the heel rolling excessively toward the midline of the body. Over time this can lead to inflexibility of the calf muscles and the Achilles tendon, which will likely lead to another common problem in the foot and ankle complex, the inability to dorsiflex. As such, overpronation is intrinsically linked to the inability to dorsiflex.
The best way to discover whether you have a normal gait, or if you overpronate, is to visit a specialty run shop, an exercise physiologist, a podiatrist or a physical therapist who specializes in working with athletes. A professional can analyze your gait, by watching you either walk or run, preferably on a treadmill. Some facilities can videotape your gait, then analyze the movement of your feet in slow-motion. Another (and less costly) way is to look at the bottom of an older pair of run shoes. Check the wear pattern. A person with a normal gait will generally see wear evenly across the heel and front of the shoe. A person who overpronates will likely see more wear on the OUTside of the heel and more wear on the INside of the forefoot (at the ball). A person who supinates will see wear all along the outer edges of the shoe. You can also learn about your gait by looking at your arches. Look at the shape your wet feet leave on a piece of paper or a flat walking surface.
Non Surgical Treatment
An overpronator is a person who overpronates, meaning that when walking or running their feet tend to roll inwards to an excessive degree. Overpronation involves excessive flattening of the arches of the feet, with the roll seeing the push off take place from the inside edge of the foot and the big toe. When this happens, the muscles and ligaments in the feet are placed under excessive strain, which can lead to pain and premature fatigue of the foot. Overpronation is most commonly experienced in people who have flat feet or fallen arches.
Calcaneal "Slide" (Sliding Calcaneal Osteotomy) A wedge is cut into the heel bone (calcaneus) and a fixation device (screws, plate) is used to hold the bone in its new position. This is an aggressive option with a prolonged period of non-weightbearing, long recovery times and many potential complications. However, it can and has provided for successful patient outcomes.