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.
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.
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.
You can test for pronation by looking at the leg and foot from the back. Normally you can see the Achilles Tendon run straight down the leg into the heel. If the foot is 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.
Non Surgical Treatment
Overpronation is a term used to describe excessive flattening of the plantar arch. Pronation is a normal part of our gait (the way we walk), and it comprises three movements: dorsiflexion, eversion, and abduction. Dorsiflexion is the upward movement of the foot, eversion describes the foot rolling in, and abduction is ?out toeing,? meaning your toes are moving away from the midline of your body. When these three motions are extreme or excessive, overpronation results. Overpronation is very common in people who have flexible flat feet. Flatfoot, or pes planus, is a condition that causes collapse of the arch during weight bearing. This flattening puts stress on the plantar fascia and the bones of the foot, resulting in pain and further breakdown.
Subtalar Arthroereisis. Primary benefit is that yje surgery is minimally invasive and fully reversible. the primary risk is a high chance of device displacement, generally not tolerated in adults.
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.