Pierrynowski M R, Smith S B
School of Rehabilitation Science, McMaster University, Hamilton, Ontario, Canada.
Foot Ankle Int. 1996 Jul;17(7):406-12. doi: 10.1177/107110079601700709.
Clinicians often fabricate foot orthotic devices at the subtalar joint neutral position (STNP) to mimic the position of the rear foot during midstance. However, rear foot motion during gait, relative to the resting standing foot position, not the STNP, is often reported in the literature. The motion of the rear foot relative to a valid estimate of the STNP is unknown. In this study, six experienced foot care specialists manually placed the rear part of the feet of nine subjects at the STNP seven or eight times to obtain a valid estimate of each subject's STNP. The worst-case mean and 95% confidence interval of the STNP estimate for any one subject was 0.0 degree +/- 0.7 degree. These nine subjects then walked on a motor-driven treadmill, set at 0.89 meters/sec, and three-dimensional estimates of each subject's rear foot inversion/eversion motion were obtained, then averaged over 6 to 26 strides. For most subjects, the rear foot was always everted during stance with mean and standard deviation maximal eversion (7.2 degrees +/- 1.2 degrees) occurring at 44% of the total gait cycle. The inversion/eversion orientation during swing was characterized by 1 degree to 2 degrees of eversion, with a small amount of inversion in early swing. These findings have implications for the fabrication of foot orthoses, since the rear foot is rarely near the STNP during stance.
临床医生常常在距下关节中立位（STNP）制作足部矫形器，以模拟站立中期后足的位置。然而，文献中经常报道的是步态期间后足相对于静息站立足部位置的运动，而非相对于STNP的运动。后足相对于STNP有效估计值的运动尚不清楚。在本研究中，六位经验丰富的足部护理专家将九名受试者足部的后部手动放置在STNP位置七到八次，以获得每位受试者STNP的有效估计值。任何一名受试者STNP估计值的最坏情况平均值及95%置信区间为0.0度±0.7度。然后，这九名受试者在设定速度为0.89米/秒的电动跑步机上行走，获得每位受试者后足内翻/外翻运动的三维估计值，并在6至26步中进行平均。对于大多数受试者，在站立期间后足始终处于外翻状态，最大外翻的平均值和标准差（7.2度±1.2度）出现在整个步态周期的44%。摆动期间的内翻/外翻方向的特征是外翻1度至2度，在摆动早期有少量内翻。这些发现对足部矫形器的制作具有启示意义，因为在站立期间后足很少接近STNP。
