Pronation occurs as weight is transferred from the heel to the forefoot and the foot rolls inwards. Or to put it a little more technically; pronation is the movement of the subtalar joint (between
the talus and calcaneus) into eversion, dorsi flexion and abduction (turning the sole outwards, upwards and sideways). A certain amount of this is natural but it many people the foot rolls in too
much or over pronates.
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.
If ignored, overpronation can lead to complications such as hammer toes, corns and calluses, shin splints, hallux rigidus and many more foot and lower leg problems. Hammer toes appear when the toes
are placed under too much pressure and the ligaments and muscles in the toes begin to reduce in size, leading to the curvature of the toes and making them look like little hammers. Overpronators can
develop hammertoes if they don?t wear an appropriate pair of shoes. Corns and calluses also appear as a result of overpronation. They form in response to excess pressure, and overpronators may find
that they have excessive hard skin on the balls of the feet and inside edge of the big toe. It is the body?s way of protecting against excessive forces and friction. They can be painful.
Firstly, look at your feet in standing, have you got a clear arch on the inside of the foot? If there is not an arch and the innermost part of the sole touches the floor, then your feet are
over-pronated. Secondly, look at your running shoes. If they are worn on the inside of the sole in particular, then pronation may be a problem for you. Thirdly, try the wet foot test. Wet your feet
and walk along a section of paving and look at the footprints you leave. A normal foot will leave a print of the heel, connected to the forefoot by a strip approximately half the width of the foot on
the outside of the sole. If you?re feet are pronated there may be little distinction between the rear and forefoot, shown opposite. The best way to determine if you over pronate is to visit a
podiatrist or similar who can do a full gait analysis on a treadmill or using forceplates measuring exactly the forces and angles of the foot whilst running. It is not only the amount of over
pronation which is important but the timing of it during the gait cycle as well that needs to be assessed.
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.
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.