The anatomy of a normal foot allows for both to occur at the same time. Approximately 30% of the population have a normal foot. The remainder of people either overpronate (95% of abnormal feet) or oversupinate (5% of abnormal feet). The important thing to know is that all feet pronate and supinate, but abnormal feet do one of these things too much or at the wrong time. When the foot overpronates or oversupinates, several foot ailments can develop.
Over-pronation is very prominent in people who have flexible, flat feet. The framework of the foot begins to collapse, causing the foot to flatten and adding additional stress to other parts of the foot. Therefore over-pronation can often lead to a case of Plantar Fasciitis, Heel Spurs, Metatarsalgia, Post-tib Tendonitis and/or Bunions. There are many causes of flat feet. Obesity, pregnancy or repetitive pounding on a hard surface can weaken the arch leading to over-pronation. People with flat feet often do not experience discomfort immediately, and some never suffer from any discomfort at all. However, when symptoms develop and become painful, walking becomes awkward and causes increased strain on the feet and calves.
It is important to note that pronation is not wrong or bad for you. In fact, our feet need to pronate and supinate to achieve proper gait. Pronation (rolling inwards) absorbs shock and supination (rolling outwards) propels our feet forward. It is our body?s natural shock-absorbing mechanism. The problem is over-pronation i.e. the pronation movement goes too deep and lasts for too long, which hinders the foot from recovering and supinating. With every step, excess pronation impedes your natural walking pattern, causing an imbalance in the body and consequent excessive wear and tear in joints, muscles and ligaments. Some common complaints associated with over-pronation include Heel Pain (Plantar Fasciitis) ,Ball of foot pain, Achilles Tendonitis, Shin splints, Knee Pain, Lower Back Pain.
A quick way to see if you over-pronate is to look for these signs. While standing straight with bare feet on the floor, look so see if the inside of your arch or sole touches the floor. Take a look at your hiking or running shoes; look for wear on the inside of the sole. Wet your feet and walk on a surface that will show the foot mark. If you have a neutral foot you should see your heel connected to the ball of your foot by a mark roughly half of width of your sole. If you over-pronate you will see greater than half and up to the full width of your sole.
Non Surgical Treatment
Over-pronation and the problems that go with it are treated with shoe inserts called arch supports or orthotics. You can buy orthotics at a pharmacy or athletic shoe store or they can be custom made. Make sure the arch supports are firm. If you can easily bend them in half, they may be too flexible.
Subtalar Arthroereisis. The ankle and hindfoot bones/midfoot bones around the joint are fused, locking the bones in place and preventing all joint motion. This may also be done in combination with fusion at other joints. This is a very aggressive option usually reserved for extreme cases where no joint flexibility is present and/or the patient has severe arthritic changes in the joint.