Pronation describes a slight inward rolling motion the foot makes during a normal walking or running stride. The foot (and ankle) roles slightly inward to accommodate movement. Some people, however, over-pronate and roll more than normal. With over-pronation, the arch of the foot flattens and causes excessive stress and pressure on the soft tissues of the foot. Over-pronation is more common in those with flat feet, and can lead to foot aches and pain, such as plantar fasciitis, Shin Splints and Knee Pain.
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.
With over pronation, sufferers are most likely to experience pain through the arch of the foot. A lack of stability is also a common complaint. Over pronation also causes the foot to turn outward during movement at the ankle, causing sufferers to walk along the inner portion of the foot. This not only can deliver serious pain through the heel and ankle, but it can also be the cause of pain in the knees or lower back as well. This condition also causes the arch to sink which places stress on the bones, ligaments, and tendons throughout the foot. This may yield other common conditions of foot pain such as plantar fasciitis and heel spurs.
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
Anti-Pronation Insoles provide a unique foot support system that aligns the lower body. The major cause of foot and leg pain is over pronation (rolling over of the feet) which causes excessive pressure on the muscles, ligaments and bones of the lower body. Running insoles treat the underlying cause of over pronation and prevent future occurrences of the associated foot or leg condition. A project conducted at the NIKE Sport Research Laboratory studied the effects of orthotics on rear foot movement in running. Nine well-trained runners who wore orthotics were chosen as subjects. The results of the study indicated that orthotics reduced rear foot movement by roughly one degree or approximately nine percent of the amount found in runners not using orthotics. The average reduction of the maximum velocity of pronation was fifteen percent. Thus this study indicates that orthotics and insoles control over pronation which will treat and prevent many sporting injuries.
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.