To develop a clinically friendly multi-segment kinematic and kinetic foot model and test it on pre-/post-HTO patients with medial knee osteoarthritis and knee varus
Abstract
This study aims to develop a clinically useful multi-segment foot model that will enable the analysis of foot kinematics and kinetics in an optical motion capture laboratory setting. This study will also test the new multi-segment foot model on patients with knee osteoarthritis and varus knee alignment that is corrected by high tibial osteotomy (HTO). 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.