Metatarsalgias and pronated foot or peritalar destabilisation syndrome?

Abstract

Pathological subtalar pronation is often referred as a biomechanical event in the pathogenesis of metatarsalgias due to destabilisation of the structures distal to the subtalar, especially when its pathological set persists during the take-off stage. The skin, the subcutaneous tissue, the metatarsal heads, the metatarsophalangeal joints, the toes and the intermetatarsal neurovascular bundles are all involved. If, however, account is taken of the fact that the normal arrangement of the subtalar joint is established by the talus, the ligaments and tendons and the suprasegmental attitude of the limb, that the subtalar and talonavicular form the so-called “coxa pedis” or peritalar joint, and that this makes a better contribution than the subtalar to the mechanism in the opening and closing of the foot's kinetic chain (talus a bone of the leg when the chain is closed, enarthrodial “coxa pedis”), it is evident that the subtalar, in the absence of any intrinsic disorder, pronates secondarily to other mechanisms to be described in each particular case. In conclusions, one can hardly speak of biomechanical metatarsalgias solely in terms of pronation of the subtalar and if we wish to call them syndromes, it is more correct to say they are the outcome of peritalar destabilisation. The term “peritalar destabilisation syndrome” offers a better access to the biomechanical event underlying global derangement of the foot and forefoot. It also corresponds to intrinsic “coxa pedis” disorders, such as recently acquired degenerative glenopathy, and obviously to the extrinsic causes of the destabilisation (skeletal, ligament, neuromuscular alterations, suprasegmental disarrangements, etc.).