Combination of pedCAT® for 3D Imaging in Standing Position With Pedography Shows No Statistical Correlation of Bone Position With Force/Pressure Distribution


      pedCAT® (CurveBeam, Warrington, PA) is a technology for 3-dimensional (3D) imaging with full weightbearing that has been proved to exactly visualize the 3D bone position. For the present study, a customized pedography sensor (Pliance; Novel, Munich, Germany) was inserted into the pedCAT®. The aim of our study was to analyze the correlation of the bone position and force/pressure distribution. A prospective consecutive study of 50 patients was performed, starting July 28, 2014. All patients underwent a pedCAT® scan and simultaneous pedography with full weightbearing in the standing position. The following parameters were measured on the pedCAT® image for the right foot by 3 different investigators 3 times: lateral talo-first metatarsal angle, calcaneal pitch angle, and minimum height of the fifth metatarsal base, second to fifth metatarsal heads, and medial sesamoid. From the pedography data, the following parameters were defined using the standardized software algorithm: midfoot contact area, maximum force of midfoot, maximum force of midfoot lateral, maximum force of entire foot, and maximum pressure of first to fifth metatarsal. The values of the corresponding pedCAT® and pedographic parameters were correlated (Pearson). The intra- and interobserver reliability of the pedCAT® measurements were sufficient (analysis of variance, p > .8 for each, power >0.8). No sufficient correlation was found between the pedCAT® and pedographic parameters (r < 0.05 or r > −0.38).3D bone position did not correlate with the force and pressure distribution under the foot sole during simultaneous pedCAT® scanning and pedography. Thus, the bone positions measured with pedCAT® do not allow conclusions about the force and pressure distribution. However, the static pedographic parameters also do not allow conclusions about the 3D bone position and force/pressure distribution are important parameters for diagnostics, planning, and follow-up examinations in foot and ankle surgery.

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