02404nas a2200229 4500000000100000008004100001653001600042653002200058653001400080653002500094653006800119653004800187100001200235700001800247700001300265700001500278245014000293300001200433490000700445520170800452022001402160 2017 d10aProsthetics10aProsthetic design10aOrthotics10aDeveloping countries10aComputer Aided Designing-Computer Aided Manufacturing (CAD-CAM)10aBiomechanics of prosthetic/orthotic devices1 aPaul SK1 aVijayakumar R1 aMathew L1 aSivarasu S00aFinite element model-based evaluation of tissue stress variations to fabricate corrective orthosis in feet with neutral subtalar joint. a157-1630 v413 a

BACKGROUND: The subtalar joint position during static stance is a crucial determinant of the peak plantar pressures and forms ideal reference point for any intervention in foot-related problems for leprosy-affected patients.

OBJECTIVES: The study pursued the hypothesis through a three-dimensional model that stress will be minimal in the distal joints of the foot when the subtalar joint is in neutral static stance position.

STUDY DESIGN: Finite element model.

METHODS: The computed tomography images of the feet for five patients suffering from Hansen's disease having no muscle weakness and joint restriction were acquired. The gray intensities corresponding to the bones of the foot from the computed tomography images were three-dimensionally reconstructed. The three-dimensional model of the human foot, incorporating the realistic geometry, and the material properties of the hard tissues were then analyzed using a finite element solver for the stress distribution on bones of the foot.

RESULTS: The results demonstrate that the position of the calcaneum in the static stance position does contribute to the varying stress in the foot.

CONCLUSION: The stresses in the bones of the foot are minimal while the subtalar is in neutral position; this position will be suitable for foot orthotic fabrication.

CLINICAL RELEVANCE: The clinicians, therapists, and podiatrists having less engineering skills can quickly assess the patient and get optimal results on the stress associated with the joints of the foot.

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