Intraoperative pedography: a validated method for static intraoperative biomechanical assessment.

Background: A new device was developed to perform intraoperative static pedography. The purpose of this study was to validate the introduced method by a comparison with the standard method for dynamic and static pedography.

Methods: A device known as Kraftsimulator Intraoperative Pedographie (KIOP) was developed for intraoperative placement of standardized forces to the sole of the foot. Pedographic measurements were done with a custom-made mat that was inserted into the KIOP (Pliance, Novel Inc., St. Paul, MN, USA). Validation was done in two steps: (1) comparison of standard dynamic pedography walking on a platform, standard static pedography in standing on a platform, and pedography with KIOP in supine position in 30 healthy volunteers, and (2) comparison of static pedography in standing position, pedography with KIOP supine awake, and pedography with KIOP supine with 30 patients under anesthesia. Individuals who had operative procedures at the knee or distal to the knee were excluded. The different measurements were compared (one-way ANOVA, t-test; significance level 0.05).

Results: No significant differences were found among all measurements for the hindfoot compared to midfoot-forefoot force distribution. For the medial compared to lateral force distribution and the 10-region-mapping, significant differences were found when comparing all measurements (steps 1 and 2) and when comparing the measurements of step 1 only. No differences were found for these distributions when comparing the measurements of step 2 alone or when comparing the measurements of step 1 and 2 without the platform measurements of step 1 (dynamic walking pedography and static standing pedography). No significant differences in the force distributions were found in step 2 when comparing subjects without anesthesia, with general anesthesia, and with spinal anesthesia.

Conclusions: The KIOP device allows a valid static intraoperative pedography measurement. No statistically significant force distribution differences were found between standing subjects and anesthetized subjects in the supine position.