Mechanical and Finite Element Analysis of an Innovative Orthopedic Implant Designed to Increase the Weight Carrying Ability of the Femur and Reduce Frictional Forces on an Amputee's Stump.

Publisher: Oxford University Press Country of Publication: England NLM ID: 2984771R Publication Model: Print Cited Medium: Internet ISSN: 1930-613X (Electronic) Linking ISSN: 00264075 NLM ISO Abbreviation: Mil Med Subsets: MEDLINE

Publication: 2018- : Oxford : Oxford University Press
Original Publication: Washington, D.C. : Association of Military Surgeons, United States, 1955-

Femur/*physiology ; Prostheses and Implants/*standards ; Weight-Bearing/*physiology; Amputation Stumps/physiopathology ; Biomechanical Phenomena ; Femur/physiopathology ; Finite Element Analysis ; Friction ; Humans ; Prosthesis Design/methods ; Prosthesis Design/standards

This study was designed to test the hypothesis that: "A properly designed implant that harnesses the principle of the incompressibility of fluids can improve the weight carrying ability of an amputee's residual femur and reduce the frictional forces at the stump external socket interface." The hypothesis was tested both mechanically on an Amputee Simulation Device (ASD) and through Finite Element Analysis (FEA) modeling software. With the implant attached to the femur, the FEA and ASD demonstrated that the femur carried 90% and 93% respectively of the force of walking. Without the implant, the FEA model and ASD femur carried only 35% and 77%, respectively, of the force of walking. Statistical calculations reveal three (3) degrees of separation (99% probability of non-random significant difference) between with and without implant data points. FEA modeling demonstrates that the normal contact forces and shear forces are pushed the distal weight-bearing area of the amputee stump, relieving the lateral stump of frictional forces. The ASD mechanical and FEA modeling data validate each other with both systems supporting the hypotheses with confidence intervals of three degrees of separation between with implant and without implant models.
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Keywords: Finite Element Analysis (FEA); Fluid Incompressibility; Normal Contact Forces (NCF); O/I output Input rations; Shear and Stress force; Von Mises forces

Date Created: 20190323 Date Completed: 20190715 Latest Revision: 20190715

20240105

10.1093/milmed/usy382

30901446