Arno Frigg, Roman Frigg, Martin Wiewiorski, Jennifer Goldoni, Monika Horisberger
Orthopedic Department, University of Basel, Basel, Switzerland.
Department of Philosophy, Logic and Scientific Method, London School of Economics, London, UK.
J Foot Ankle Res. 2016 Dec 1;9:47. doi: 10.1186/s13047-016-0177-y. eCollection 2016.
Pedobarography offers dynamic information about the foot, but the interpretation of its large data is challenging. In a prior study it was shown that attention can be restricted to pedobarographic midfoot load data. We aim to verify this observation in ankle osteoarthritic and contralateral feet.
We assessed both feet of 120 patients with end-stage ankle osteoarthritis (OA) and 35 healthy volunteers with AOFAS-score and dynamic pedobarography in barefoot condition. We introduce a new parameter, the Relative Midfoot Index (RMI), representing the depth of the midfoot weighted by the maximal force (MF) in the hindfoot and forefoot. Main outcome measures were the RMI, MF and contact times in the hindfoot, midfoot and forefoot. Ankle OA, contralateral and healthy feet were compared with ANOVA.
The RMI was significantly smaller in OA feet (0.65 ± 0.19) and contralateral feet (0.69 ± 0.15) than in healthy feet (0.84 ± 0.08, 0.0001). There was no significant difference between OA and contralateral feet. The RMI showed a correlation of 0.48 with the AOFAS score. Contralateral and OA feet were significantly different from healthy feet ( 0.001) in all parameters except the hindfoot MF. An RMI <0.8 showed a positive predictive value of 80% and sensitivity of 78% for being unhealthy.
The RMI assists the interpretation of pedobarographic parameters and provides a user-friendly indicator for unhealthy foot conditions with a cut-off value of 0.8. The contralateral feet of ankle OA patients differed significantly from healthy feet and are therefore not suitable as control group. Level of Evidence: 3 case control study.
足底压力测量法可提供有关足部的动态信息，但其大量数据的解读具有挑战性。在先前的一项研究中表明，可以将注意力限制在足底压力测量的中足负荷数据上。我们旨在在踝骨关节炎患者及其对侧足部中验证这一观察结果。
我们评估了120例终末期踝骨关节炎（OA）患者的双足以及35名健康志愿者的双足，采用美国足与踝关节协会（AOFAS）评分和在赤足条件下的动态足底压力测量法。我们引入了一个新参数，相对中足指数（RMI），它代表中足深度，由后足和前足的最大力（MF）加权得出。主要观察指标为RMI、MF以及后足、中足和前足的接触时间。采用方差分析比较踝OA、对侧足部和健康足部。
OA患足（0.65±0.19）和对侧足部（0.69±0.15）的RMI显著小于健康足部（0.84±0.08，P<0.0001）。OA患足和对侧足部之间无显著差异。RMI与AOFAS评分的相关性为0.48。除后足MF外，对侧足部和OA患足在所有参数上与健康足部均有显著差异（P<0.001）。RMI<0.8对足部不健康的阳性预测值为80%，敏感性为78%。
RMI有助于解读足底压力测量参数，并为不健康的足部状况提供了一个截止值为0.8的用户友好型指标。踝OA患者的对侧足部与健康足部有显著差异，因此不适合作为对照组。证据级别：3级病例对照研究。
