Assessment of rearfoot motion: passive positioning, one-legged standing, gait

Earlier studies that address assessment of the subtalar joint (STJ) by measuring rearfoot motion used a goniometer to evaluate intertester reliability. Few investigations have determined how positions of the rearfoot, assessed manually (passive range of motion) or statically in one-legged standing, compare with those occurring during walking. The purpose of this study was to determine the following: (1) the intertester reliability of positioning the STJ in neutral, maximum inversion, and maximum eversion; (2) the reliability of the rearfoot position during relaxed one-legged standing; and (3) how these positions compare to rearfoot motion during walking. An electrogoniometer attached to the lateral aspect of the lower leg and heel was used to record the position of the rearfoot during testing procedures. Ten healthy volunteers participated. Rearfoot position was recorded during relaxed one-legged standing and during free and fast walking. Additionally, rearfoot position was recorded while each of three physical therapists positioned the STJ in neutral, maximum inversion, and maximum eversion. Intertester reliability for positioning the STJ in neutral, maximum inversion, and maximum eversion yielded intraclass correlation coefficients of 0.76, 0.37, and 0.39, respectively. Reliability of relaxed one-legged standing had an intraclass correlation coefficient of 0.92. The rearfoot position in relaxed one-legged standing and the maximum eversion position occurring during gait were not significantly different. These findings suggest that there is good intertester reliability in positioning the STJ in neutral. Additionally, the rearfoot position in relaxed one-legged standing may be used to approximate the maximum eversion position that occurs during gait.