Over-Pronation

Overview

Pronation is a turning outward of the foot at the ankle, which allows the foot to flatten. The pronation helps to absorb some of the compressive shock forces, torque conversion, adjustment to uneven ground contours, and maintenance of balance. It is necessary to have a certain amount of pronation to disseminate the energy of the foot-strike. If there is too little or too much pronation injuries may occur. When a foot and ankle pronates to a great degree, we call it over-pronation. Normally you can see the Achilles Tendon run straight down the leg into the heel. If the foot is over-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.Foot Pronation

Causes

There are many biomechanical issues that can contribute to excessive pronation, including weak foot intrinsic muscles, limited ankle dorsiflexion mobility and calf flexibility, weak ankle invertor muscles (e.g. posterior tibialis), weak forefoot evertor muscles (peroneus longus), poor hip strength and control, Anterior pelvic tilting, heel InversionIn a person who overpronates, the heel bone goes into an everted position meaning that it turns out away from the midline of the body. The opposite motion of eversion is inversion. Inversion is a motion that needs to be controlled to prevent the foot from excessively pronating.

Symptoms

Overpronation can lead to injuries and pain in the foot, ankle, knee, or hip. Overpronation puts extra stress on all the bones in the feet. The repeated stress on the knees, shins, thighs, and pelvis puts additional stress on the muscles, tendons, and ligaments of the lower leg. This can put the knee, hip, and back out of alignment, and it can become very painful.

Diagnosis

If you have flat feet or low arches, chances are you overpronate. Although not always the case, the lower your arches the greater the overpronate. Stand on a hard surface (in front of a mirror if you need to) and look at your feet, flat feet or low arches are easy to spot. If your feet look flatter than a pancake, have a look at your ankles and see if they seem collapsed or straight. If they are, you're overpronating.Over-Pronation

Non Surgical Treatment

Adequate footwear can often help with conditions related to flat feet and high arches. Certified Pedorthists recommend selecting shoes featuring heel counters that make the heel of the shoe stronger to help resist or reduce excessive rearfoot motions. The heel counter is the hard piece in the back of the shoe that controls the foot?s motion from side-to-side. You can quickly test the effectiveness of a shoe?s heel counter by placing the shoe in the palm of your hand and putting your thumb in the mid-portion of the heel, trying to bend the back of the shoe. A heel counter that does not bend very much will provide superior motion control. Appropriate midsole density, the firmer the density, the more it will resist motion (important for a foot that overpronates or is pes planus), and the softer the density, the more it will shock absorb (important for a cavus foot with poor shock absorption) Wide base of support through the midfoot, to provide more support under a foot that is overpronated or the middle of the foot is collapsed inward.

Surgical Treatment

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.

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