THE RELATIONSHIP OF STATIC FOOT STRUCTURE TO DYNAMIC FOOT FUNCTION

Many theories have been advanced concerning the relationship between s tructure and function in the human foot, yet few of these theories hav e been subjected to quantitative examination. In this study, foot stru cture was characterized by 27 measurements taken from standardized lat eral and dorsi-plantar weight-bearing plain radiographs of 50 healthy adult subjects. Regional plantar pressure distribution data collected from the same feet were chosen as the functional measures. A stepwise regression analysis was performed to (1) explore what portion of the v ariance in peak plantar pressure during walking can be explained by th e radiographic measurements, and (2) identify structural characteristi cs of the foot which are significant predictors of peak plantar pressu re under the heel and the first metatarsal head (MTH1). Most of the ra diographic measurements were highly reliable. However, only 31 and 38% of the variance in peak plantar pressure at the heel and MTH1, respec tively, could be explained using multiple regression analyses with the radiographic measurements as independent variables. Among the structu ral predictors that were identified, soft tissue thickness (e.g. calca neus or sesamoid heights), and arch-related measurements were the stro ngest predictors of plantar pressure under both the heel and the first metatarsal head. We conclude that, in normal subjects, only about 35% of the variance in dynamic plantar pressure can be explained by the m easurements of foot structure derived from radiographs. This implies t hat the dynamics of gait are likely to exert the major influence on pl antar pressure during walking. (C) 1997 Elsevier Science Ltd.