Foot kinematics in patients with two patterns of pathological plantar hyperkeratosis

Twenty-seven subjects with planter pathological hyperkeratosis were recruited into one of two groups. Group 1 displayed pathological plantar hyperkeratosis only under metatarsal heads 2, 3 and 4 (n = 14). Group 2 displayed pathological plantar hyperkeratosis only under the 1st and 5th metatarsal heads (n = 13). Foot kinematics were measured using reflective markers on the leg, heel, midfoot, first metatarsal and hallux.The kinematic data failed to identify distinct differences between these two groups of subjects, however there were several subtle (generally <3°) differences in kinematic data between these groups. Group 1 displayed a less everted heel, a less abducted heel and a more plantarflexed heel compared to group 2, which is contrary to the Root paradigm.There was some evidence of small differences between planter pathological hyperkeratosis groups. Nevertheless, there was too much similarity between the kinematic data displayed in each group to classify them as distinct foot types as the current clinical paradigm proposes.Clinical diagnosis and orthotic management of mechanically related foot disorders is founded on a the generally accepted Root et al [1,2] paradigm of foot function. This paradigm was developed in response to a clinical need for a conceptual framework to classify and explain foot pathologies. Despite a lack of kinematic data supporting such concepts, 'mobile' and 'rigid' foot types are central to the paradigm. The belief is that the mobile foot type is characterised by a more everted heel and a lower medial arch profile compared to the rigid foot type. The assumed differences in foot kinematics between the mobile and rigid foot types are associated with similarly distinct patterns of load distribution under the forefoot. For the mobile foot type pressure is primarily located under the second and third metatarsal heads. This is said to be a consequence of medial distribution of load under the forefoot due to rearfoot eversion and dorsiflexion