Effect of the Prefabricated Plantar Insoles to Control Pronation Measured With Foot Posture Index

Nowadays several treatments have been described to treat pronation foot posture, althought these ones heven´t proved objetively the improvement and progression of foot deformity like "Foot Posture Index" does,. Foot pronation during walking is a physiological movement at the beginning of stance phase. It is a needed mechanism which allows the lower limb muscles to support the reaction forces from the ground and to give the forefoot wider range of movement . When there is pronation movement in weight bearing of subtalar joint, the calcaneus does a movement of eversión while talus does a plantarflexion and movement of aduction .The movement is raised due to the paralelism of midfoot joints and the forefoot is forced to compensate the rearfoot position, gettting into dorsiflexion and abduction which leads to a flattening of the medial arch. it is known pronation or flatfoot. Pronation movement is a pathology when it happens during the second part of the stance phase, the 25% at the beginning or when deformity is abnormal provoking an excessive rearfoot eversion with flattenig of the medial arch which will lead to a lower limb misalignment . This doesn´t allow the foot to be a rigid part needed to propulsion phase, so muscles must work excessively to give balance. The pronated foot etiology can be congenital or laxity or due to triceps sural shortening, or functional etiology like varus forefoot, metatarsus aductus or tibial posterior insufficiency. There are some secundary painful pathologies which are the most frequent reason of podiatric appointment.. Plantar fascitis is one of the pathologies, and adquired deformities like Hallux Abductus Valgus, Hallux Límitus/Rigidus and other lower limb deformities like medial compatiment ostheoartritis of knee or patellofemoral syndrome.

Pronated foot can be defined like a foot that has rearfoot eversion and medial protusion of the head of talus, forefoot abduction, flatted medial arch and joint movement greater. This shows a flat foot aspect, depending on the grades of pronation deformity that pacient presents. Both situations are linked and their behaviour are functionally similar.

Attending on consequences and the pathologies derivated of this deformity there are some treatments to stop it and avoid structural alterations of leg and foot. For instance, hallux abductus Valgus, the pathological pronation is the first ray´s extrinsic ethilogic factor, both frequency and capacity to produce pathology.

The compensation of pathological pronation of rearfoot is important to control the deformity evolution. Is commonly accepted by podiatric scientific community that control of pronation can avoid the deformity progression when it is presented (or this progression was slower) and avoid when it wasn´t present yet. Foot Posture Index is a clinical diagnostics tool compounds by 6 criteria that allow to asses reliability the weightbearing foot posture. It is a inexpensive and simple method that doesn´t imply risks to people.