Progress

1. Progress 2010/3/11 報告學生：陳謀法 指導教授：楊世偉

2. Pre-works before simulation • Calculate the loading of the different cases • Predict to the implant length by the small finite element method

3. How to decide to the loading of the different transfemoral amputees?

4. Mean amputee data High:178cm Total mass:84.3kg Residual limb length:20cm Data analysis Step1:Calibration Step2:Selection of relevant segment of data to analyze Step3:Determination of gait events Parameters Patterns of curves Local extrema Impulse values W.C.C. Lee : Clinical Biomechanics 22 (2007) 665–673

5. Last stance phase Short moment arm Early stance phase W.C.C. Lee : Clinical Biomechanics 30 (2008) 825–833

6. 13% gait cycle FAP = 15%BW FML = -15%BW FL = 120%BW 13% gait cycle MAP = 30 + ∆RL*FML MML = -18 + ∆ RL*FAP ML = 5 13%

7. Hip reaction force • Standing:15%BW • Squatting:100%BW • Standing by single leg:250%BW • Laying:150%BW • Normal walking:700%BW • Fast running:1000%BW • Mass 70kg corresponds to 4.3 times body weight for joint reaction force and abduction M.E. Taylor : Med. Eng. Phys. (1996) Vol. 18. No. 2, pp. 122-133

8. AP-view M.E. Taylor : Med. Eng. Phys. (1996) Vol. 18. No. 2, pp. 122-133

9. Simulation • Finite element analysis • Model(part and material) • Interaction(constrain) • Load(boundary condition)

10. Data analysis • Femur • Micro-brittle • Maximum principle stress • Maximum principle strain • Weibull modulus • Implant • Ductile • Principles of fracture mechanics • Von-Mises stress

11. Principles of implant design • Shape (triangle thread implant) • Single thread • Multiple thread • Hi-Lo type double thread http://www.cpami.gov.tw/

12. Principles of implant design • Diameter • Pilot hole diameter (16mm) • Core diameter (16/0.9=18mm) Cortical bone has an average apparent density of approximately 1.9 g/cm3 Reilly, D.T. and Burstein, A. H. J. Biomechanics , 8, 393-405, 1975

13. Principles of implant design • Triangle thread diameter • σt= Tensile Strength (kg/cm2) • W= Axial load (kg) • d1= Core diameter (cm) 大西清 ,JIS standard drawn method,1955

14. Principles of implant design • Thread number • q= Contact pressure (kgf/cm2) • n= Pitch number • W= Axial load (kg) • d= Major diameter (cm) [range:20.38~21.36mm] • d1= Core diameter (cm)[18mm] 大西清 ,JIS standard drawn method,1955

15. Principles of implant design • Allowable drawing force • Pw= Allowable drawing force(kgf/cm) • ρ= Bone density • d= Major diameter (cm) http://www.cpami.gov.tw/

16. Principles of implant design • Allowable shear force • Pa= Allowable shear force (kgf) • ρ= Bone density • d= Major diameter (cm) • l= Implant length (cm) http://www.cpami.gov.tw/

17. Conclusion • Predict the loading of the different cases by their body weight • Follow the mechanical principal to decide to the implant • Shape • Single thread • Multiple thread • Hi-Lo type double thread • Diameter • Pilot hole diameter (16mm) • Core diameter (18mm) • Major diameter (21mm) • Pitch number (n>1) • Length (l/d=4~10) • Pitch • Coarse thread(2.5mm) • Fine thread (1mm、1.5mm、2mm) • Angle • Coarse thread(60o) • Fine thread(550、58o)

18. Futurework • CreatetheabovementionedimplantbySoildwork • Makethecriteriaandsummaryoffracturetheory • RunthefiniteelementanalysisbyAbaqus