The purpose of this study was to clarify the effect of the use of plantar foot orthoses on the cooperative kinematic patterns of the hindfoot and lower leg in patients with CAI.
Six patients with CAI were included in the study.
The task was a 10-m straight line walk with a stride length of 60 cm and a cadence of 110 steps/min. A three-dimensional motion analyzer and a floor reaction force meter were used.
Heel wedges, medial longitudinal arch pads, and metatarsal pads were applied directly to the plantar foot.
Data were normalized to 100% for one gait cycle and averaged over 5 cycles. The data employed were lower limb joint angles and lower limb joint moments. Among the joint angles, the hindfoot angle inward/outward was calculated as the angle of the hindfoot to the lower leg on the forehead plane, and the lower leg angle of internal/external rotation was calculated as the angle of the lower leg to the hindfoot on the horizontal plane.
To evaluate the kinetic chain of the hindfoot and lower leg from the obtained angle data, an angle-angle diagram was created from the hindfoot and lower leg angles, and the angle between the plotted values was calculated. Then, we classified the subjects into four coordinated kinematic patterns based on the magnitude of the angles.
For statistical analysis, we compared the lower limb joint angles and joint moments of the two groups before and after the use of insoles. A chi-square test was performed for differences in the coordinated movement patterns. SPSS 12.0 was used for statistical processing, and the significance level was set at 5%.
There were no significant differences in joint angles and joint moments during walking between the two groups.
In terms of the coordinated movement patterns, the hindfoot inward rotation and lower leg internal rotation patterns were more common after using the insoles during 0 to 20% of the gait cycle than in the normal group. The hindfoot external rotation/external rotation patterns were more frequent after using the insoles for 20-30% of the gait cycle.
In CAI cases, it has been reported that the load shifts outward, resulting in the appearance of rearfoot inward and lower leg outward rotation, or compensatory rearfoot outward and lower leg inward rotation. It was found that the use of insoles can cause internal rotation of the lower leg while inhibiting excessive external rotation of the hindfoot.
The results of this study suggest that insole therapy for gait in CAI cases can change the coordinated movement pattern.
gait
modified vector coding technique
