There may be stretching of the plantar calcaneonavicular ligament (spring ligament) and the tibialis posterior tendon. Pes planus results in flattening of the medial longitudinal arch (MLA), with secondary effects including medial navicular prominence, hind foot eversion, secondary hallux valgus and crowding of the lesser toes. The elasticity of these arches makes walking and running more efficient in terms of energy consumption, as well as dissipating much of the force incurred in locomotion before it reaches the more proximal lower limb.
The cuboid, navicular and three cuneiform bones help form the two longitudinal arches and single transverse arch of each foot (Figure 1). The foot can be sub-divided into the hindfoot, midfoot and forefoot. There are 26 bones and 33 joints in the human foot and ankle, controlled and stabilised by multiple muscles, tendons and ligaments. The foot is the complex ‘terminal organ’ of weight bearing and locomotion. The goal is not usually to permanently reverse the changes in the foot and ankle, but rather to help limit progression of the deformity and reduce the rate of chronic, secondary complications up the kinetic chain. 2,6,7 However, there is increasing evidence that non-surgical interventions, such as orthoses and physiotherapy, may be beneficial for certain groups of children.
Paediatric flat foot (pes planus) treatment is a somewhat controversial topic, with a lack of clarity in the literature regarding which children require treatment, as well as the efficacy of intervention. 1 Flexible flat feet can be part of an otherwise normal developmental profile, and foot arches usually develop with age however, there is a wide range of normal variation. Flat feet are relatively common in childhood, affecting up to 14% of children.