Variability of neutral-position casting of the foot.

Neutral-position casting of the foot is used for the manufacture of functional foot orthoses, and an accurate cast is widely assumed to be a prerequisite for a good orthotic device. The primary aim of this study was to determine the variability of casting between inexperienced and experienced clinicians and the variability of one experienced clinician taking multiple casts. Ten inexperienced and ten experienced clinicians took a cast of the right foot of a single subject, and a single experienced clinician took ten casts of the same foot. The frontal plane forefoot-to-rearfoot relationship of each cast was determined, and no difference was found in the mean and variances among the three groups. The range of the forefoot-to-rearfoot relationship across all groups was from 10.0 degrees everted to 6.5 degrees inverted, indicating that there is a wide range in neutral-position casting of the foot. As outcome studies have reported the successful outcomes of functional foot orthoses, this wide variability may not necessarily be a problem.