Foot function and normal coronal plane range-of-motion at the ankle-joint-complex

Abstract

An investigation was carried out into normal coronal plane range-of-motion at the ankle-joint-complex. To facilitate this, an accurate and reliable measurement rig was designed. The range of motion at the ankle joint complex was measured in one hundred subjects of both sexes (mean age 24.6, range 18-49) by applying a torque of 4Nm to an axis which deviated medially by 16 degrees. The results showed a mean equilibrium position of 19.5 degrees inverted, a mean total range of motion from the equilibrium position of 66.15 degrees, and a mean total inversion value from horizontal of 64.4 degrees. Three further experiments were carried out. The purpose of these was to examine diurnal variation in range of motion (n = 7), to examine the effect of rig axis position on the range of motion (n = 15), and to look for any difference in ankle joint complex range of motion in those patients with symptoms proximal to the ankle, and those with symptoms distal to the ankle (n = 20). Significant differences in measurement for each variable at each time interval for all subjects were observed, and significant differences in range of motion were found for each measurement, apart from inversion, when movement around different axis orientations were compared. Similar inversion values are due to the difference m equilibrium position between an axis bisecting the foot and an axis which deviates by 16 degrees medially, and a comparison of inversion values from horizontal show a mean difference of 27 degrees. No significant difference m range of motion was found in a comparison study of patients with symptoms distal and proximal to the ankle joint complex. The findings of this study have important implications both for clinical practice in the field of foot and ankle treatment, and for further research into ranges of motion at the ankle joint complex.