Subtalar neutral position as an offset for a kinematic model of the foot during walking
- 作者：Jeff R. Houck ; Josh M. Tome ; Deborah A. Nawoczenski
- 关键词：Foot ; Kinematics ; Subtalar neutral ; Gait
- 刊名：Gait and Posture
- 出版年：2008
- 期刊代码：106_09666362
- 类别：med
- 出版时间：July 2008
- 卷：28
- 期：1
- 页码：29-37
- 文件大小：550 K
摘要
The lack of a common reference position when defining foot postures may underestimate the ability to differentiate foot function in subjects with pathology. The effect of using the subtalar neutral (STN) position as an offset for both rearfoot and forefoot through comparison of the kinematic walking patterns of subjects classified as normal (n = 7) and abnormally pronated (n = 14) foot postures was completed. An Optotrak™ Motion Analysis System (Northern Digital, Inc.) integrated with Motion Monitor Software™ (Innovative Sports, Inc.) was used to track three-dimensional movement of the leg, rearfoot and first metatarsal segments. Intrarater reliability of positioning the foot into STN using clinical guidelines was determined for a single rater for 21 subjects. Walking data were subsequently compared before and after an offset was applied to the rearfoot and first metatarsal segments. Repeated measures of foot positioning found the STN position to be highly repeatable (intraclass correlation coefficients > 0.9), with peak errors ranging from 1.9° to 4.3°. Utilizing STN as the offset resulted in a significant increase in rearfoot eversion (p = 0.019) during early stance, and greater first metatarsal dorsiflexion (p < 0.007) across stance in the pronated foot groups that was not observed prior to applying the offset. When applied to subjects with differing foot postures, the selection of a common reference position that is both clinically appropriate and reliable may distinguish kinematic patterns during walking that are consistent with theories of abnormal pronation.