Title : Development of a clinically useful multi-segment kinetic foot model
Abstract:
Traditionally, gait analysis studies record the foot as a single rigid segment, leaving movements and loads within the foot undetected. In addition, very few data of multi-segment foot kinetics have been represented in the literature due to measurement and equipment limitations. As a result, this study aims to develop a novel multi-segment kinetic foot model that is clinically feasible and enables both kinematic and kinetic analysis of large patient groups.
The multi-segment foot model divides the foot into four functional segments: the hindfoot, midfoot, forefoot and hallux. An X-Z-Y-Cardan angle rotation convention was used to determine intersegmental dorsi/plantar flexion, inversion/eversion, and internal/external rotation. Joint moments, joint powers and medio-longitudinal arch (MLA) height/length ratio were also measured. Ten healthy adults and four HTO patients were tested with an optical motion capture system as they walked barefoot in their self-selected speeds. Repeatability of joint motions was calculated using coefficients of multiple correlation. Outcome measures were compared with other multi-segment foot models found in the biomechanics literature to assess validity.
This novel multi-segment foot model showed strong test-retest and within-subject reliability (R>0.7) for most joint motions (24/27) in healthy adults. The model was sensitive enough to detect abnormal foot motions, including lower MLA, increased hallux abduction, in patient gait compared to the normal cohort. This novel model has been shown to be a clinically useful tool for research and assessment on clinical populations. This model is currently being used on knee OA patients before and after HTO to explore how foot dynamics may change in response to knee alignment correction.
