Portable soft tissue indentor for use in clinical settings

The authors have designed, built, and tested a portable indentor device that allows them to determine force/displacement (F/D) measurements on the plantar foot in the clinic. The results collected with this device will be used for applications in modeling the foot and for orthotic fabrication. The indentor system consists of a load cell mounted on a three-dimensional measurement device (Metrecom). The output of the load cell and the Metrecom are recorded and analyzed by software running on a notebook computer. The distance calibration of the Metrecom gave an average error=0.34 mm (SD=0.66). The force calibration of the load cell resulted in an average error=0.022 N (SD=0.049). The device was linear and accurate for measuring force per unit displacement. The indentor device also was tested on three orthotic materials, with obtained values similar to those measured using a Materials Testing System. Initial tests on subject have shown acceptable repeatability and sensitivity to identify differences in F/D curves between subjects.