What is the pathology of flat feet?
We usually speak of flat feet when there is a decrease in the height of the longitudinal arch of the sole of the foot. In general it is accompanied by an outward deviation of the heel (what we call talo valgus) and for this reason it is usually called flat-valgus foot.
In children there are basically two types of flatfoot, the flexible flatfoot and the rigid flatfoot.
The flexible flatfoot is characterized as a foot with a normal skeletal structure but with a lot of flexibility in its joints. Therefore, when the child stands up and supports his weight, the bridge sinks and the heel deviates outwards. However, when we make the child stand on tiptoe, the bridge reappears and the heel is corrected inwards. This is the most common type of foot in children and is considered a normal situation during the first years of life.
Rigid flat feet are characterized by abnormal joints between the bones of the foot. This results in a deformity with a lower longitudinal arch height and a valgus deviation of the heel. When the child stands on tiptoe, the posture of the foot does not change because the mobility is blocked by the union between the bones. This situation is definitive and does not change with age.
At what age does it usually manifest itself?
Most children under 5 years of age usually have flexible flat feet. In addition, during the first two years of life there is usually an accumulation of fatty tissue in the area of the longitudinal arch that increases the appearance of flat feet. Normally the height of the longitudinal arch increases progressively during the first years of life, by the age of 10 years it presents a normal foot appearance and in adolescence it is completely formed.
However, there is a wide range of normal longitudinal arch height. In general, girls tend to have a somewhat more pronounced arch than boys. And in fact, up to 20% of the population never develop a clear longitudinal arch and have painless, functional, flexible flat feet throughout life. Therefore, we now consider the flexible flatfoot as a variant of normality.
However, a very pronounced flexible flatfoot causes difficulties with footwear, rubbing on the inner side and even pain during physical activities. This symptomatology usually appears after the age of 10 and especially in adolescence, because the mechanical load on the foot increases due to the greater weight of the body and the fact that they normally do more physical activity.
Rigid flat feet due to abnormal bony unions do not improve during growth and from the age of 10 years onwards can cause discomfort, often in the peroneal tendons (behind the fibula in the ankle) as they contract when trying to move joints that are rigid due to the bony union. In addition, this bony union hinders the ability of the foot to adapt to the irregularities of the terrain and patients often have repeated ankle sprains. Therefore, a child with recurrent sprains should be checked for bony alterations in the foot.
How do I know if my child has flat feet?
The examination is very simple. You should stand behind the child and observe how he/she supports his/her feet. If you notice the absence of longitudinal arch and a heel that is very deviated outwards, you have a flat-valgus foot.
Then you should tell him to stand on tiptoe. If, when doing so, the longitudinal arch appears and the heel corrects itself and turns inward, it is a flexible flat foot that should not be a cause for concern. If, when standing on tiptoe, there is no longitudinal arch and the heel is not corrected, it is probably a rigid flat foot and you should consult your pediatric orthopedist.
Do flat feet have a solution and what is the surgical treatment?
In general, we consider that flexible flat feet do not require treatment. The use of insoles has been shown to be ineffective in causing an increase in the longitudinal arch, but its effect is the opposite, given that by increasing the rigidity of the sole of the shoe, it hinders the stimulus of development of the internal musculature of the foot and its use is associated with persistent flatfoot. In general, it is recommended to perform activities that develop the intrinsic internal musculature of the foot, such as walking on tiptoe, walking on the sand at the beach or walking at home barefoot (or with non-slip socks).
In cases of very accentuated flexible flatfoot, with pain or difficulty with footwear, there are several reconstructive surgical options. The simplest is to place a rigid support between the talus and calcaneus bones that prevents longitudinal arch collapse and heel valgus deformity. This support is usually maintained for a couple of years and then removed. In very severe cases there are other more complex reconstructive techniques.
In cases of rigid flatfoot with few symptoms, rehabilitation treatment that reverses the contracture of the peroneal musculature is usually sufficient. If there are very repeated sprains or pain that does not subside with rehabilitation treatment, surgery for resection of the anomalous bony joint should be considered.