Flat feet

Since children are unlikely to suspect or identify flat feet on their own, it is important for adult caregivers to check on this themselves. Besides visual inspection of feet and of the treadwear pattern on shoe soles, caregivers should notice when a child's gait is abnormal or the child seems to be in pain from walking. Children who complain about calf muscle pains, arch pain, or any other pains around the foot area may be developing or have developed flat feet.

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  Lateral X-ray of a flat foot with C-sign, which is a bony bridge between the talar dome and sustentaculum tali, in combination with a prominent inferior border of the sustentaculum tali. This represents a talocalcaneal coalition, which is an abnormal connection between the talus and calcaneus, and is thought to cause the flat foot deformity in this case.[5]

Training of the feet, utilizing foot gymnastics and going barefoot on varying terrain, can facilitate the formation of arches during childhood, with a developed arch occurring for most by the age of four to six years. Ligament laxity is also among the factors known to be associated with flat feet. One medical study in India with a large sample size of children who had grown up wearing shoes and others going barefoot found that the longitudinal arches of the bare-footers were generally strongest and highest as a group, and that flat feet were less common in children who had grown up wearing sandals or slippers than among those who had worn closed-toe shoes. Focusing on the influence of footwear on the prevalence of pes planus, the cross-sectional study performed on children noted that wearing shoes throughout early childhood can be detrimental to the development of a normal or a high medial longitudinal arch. The vulnerability for flat foot among shoe-wearing children increases if the child has an associated ligament laxity condition. The results of the study suggest that children be encouraged to play barefooted on various surfaces of terrain and that slippers and sandals are less harmful compared to closed-toe shoes. It appeared that closed-toe shoes greatly inhibited the development of the arch of the foot more so than slippers or sandals. This conclusion may be a result of the notion that intrinsic muscle activity of the arch is required to prevent slippers and sandals from falling off the child's foot.[6] In children with few symptoms orthotics are not recommended.[7]

Research has shown that tendon specimens from people who have adult-acquired flat feet show evidence of increased activity of proteolytic enzymes. These enzymes can break down the constituents of the involved tendons and cause the foot arch to fall. In the future, these enzymes may become targets for new drug therapies.[9]

Many medical professionals can diagnose a flat foot by examining the patient standing or just looking at them. On going up onto tip toe the deformity will correct when this is a flexible flat foot in a child with lax joints. Such correction is not seen in adults with a rigid flat foot.

An easy and traditional home diagnosis is the "wet footprint" test, performed by wetting the feet in water and then standing on a smooth, level surface such as smooth concrete or thin cardboard or heavy paper. Usually, the more the sole of the foot that makes contact (leaves a footprint), the flatter the foot. In more extreme cases, known as a kinked flatfoot, the entire inner edge of the footprint may actually bulge outward, where in a normal to high arch this part of the sole of the foot does not make contact with the ground at all.

On plain radiography, flat feet can be diagnosed and graded by several measures, the most important in adults being the talonavicular coverage angle, the calcaneal pitch, and the talar-1st metatarsal angle (Meary's angle).[10] The talonavicular coverage angle is abnormally laterally rotated in flat feet.[10] It is normally up to 7 degrees laterally rotated, so a greater rotation indicates flat feet.[10] Radiographies generally need to be taken on weightbearing feet in order to detect misalignment.[11]

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  Dorsoplantar projectional radiograph of the foot showing the measurement of the talonavicular coverage angle.
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  Weight-bearing lateral X-ray showing the measurement of calcaneal pitch, which is an angle of the calcaneus and the inferior aspect of the foot, with different sources giving different reference points.[12] A calcaneal pitch of less than 17° or 18° indicates flat feet.[10]
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  Same lateral X-ray showing the measurement of Meary's angle, which is the angle between the long axis of the talus and first metatarsal bone.[10] An angle greater than 4° convex downward is considered a flat foot, 15° - 30° moderate flat foot, and greater than 30° severe flat foot.[10]

Most flexible flat feet are asymptomatic, and do not cause pain. In these cases, there is usually no cause for concern. Flat feet were formerly a physical-health reason for service-rejection in many militaries. However, three military studies on asymptomatic adults (see section below), suggest that persons with asymptomatic flat feet are at least as tolerant of foot stress as the population with various grades of arch.

In a study performed to analyze the activation of the tibialis posterior muscle in adults with pes planus, it was noted that the tendon of this muscle may be dysfunctional and lead to disabling weightbearing symptoms associated with acquired flat foot deformity. The results of the study indicated that while barefoot, subjects activated additional lower-leg muscles to complete an exercise that resisted foot adduction. However, when the same subjects performed the exercise while wearing arch supporting orthotics and shoes, the tibialis posterior was selectively activated. Such discoveries suggest that the use of shoes with properly fitting, arch-supporting orthotics will enhance selective activation of the tibialis posterior muscle thus, acting as an adequate treatment for the undesirable symptoms of pes planus.[13]

Rigid flatfoot, a condition where the sole of the foot is rigidly flat even when a person is not standing, often indicates a significant problem in the bones of the affected feet, and can cause pain in about a quarter of those affected.[14][15] Other flatfoot-related conditions, such as various forms of tarsal coalition (two or more bones in the midfoot or hindfoot abnormally joined) or an accessory navicular (extra bone on the inner side of the foot) should be treated promptly, usually by the very early teen years, before a child's bone structure firms up permanently as a young adult. Both tarsal coalition and an accessory navicular can be confirmed by X-ray. Rheumatoid arthritis can destroy tendons in the foot (or both feet) which can cause this condition, and untreated can result in deformity and early onset of osteoarthritis of the joint. Such a condition can cause severe pain and considerably reduced ability to walk, even with orthoses. Ankle fusion is usually recommended.[16]

Treatment of flat feet may also be appropriate if there is associated foot or lower leg pain, or if the condition affects the knees or the lower back. Treatment may include foot gymnastics or other exercises as recommended by a podiatrist or physical therapist. In cases of severe flat feet, orthoses should be used through a gradual process to lessen discomfort. Over several weeks, slightly more material is added to the orthosis to raise the arch. These small changes allow the foot structure to adjust gradually, as well as giving the patient time to acclimatise to the sensation of wearing orthoses. In some cases, surgery can provide lasting relief, and even create an arch where none existed before; it should be considered a last resort, as it is usually very time-consuming and costly.[17] A minimally-invasive surgical intervention involving a small implant is also available. The implant is inserted into the sinus tarsi and prevents the calcaneus and talus from sliding relative to each other. This prevents the sinus tarsi from collapsing and thus prevents the external symptom of the fallen arch from occurring.[18]