Author :Frank Heuer, Mark Sommers, John B. Reid III, Michael Bottlang

1. ESTIMATION OF CARTILAGE THICKNESS FROM JOINT SURFACE SCANS:COMPARATIVE ANALYSIS OF COMPUTATIONAL METHODS Author :Frank Heuer, Mark Sommers, John B. Reid III, Michael Bottlang Source :BED-Vol. 50, 2001 Bioengineering Conference ASME 2001 Speaker : Ren-LI Shen Advisor : Ku-Yaw Chang

2. Outline • Introduction • Materials and methods • Result • Discussion

3. Introduction • Cartilage thickness and volume • characterize normal joints • delineate joint degenerative disease • Compute cartilage thickness and volume from high-resolution joint geometry scans • three distinct algorithms

4. Outline • Introduction • Materials and methods • Result • Discussion

5. Materials and methods • Joint of a human cadaveric talus • obtained a laser displacement sensor • scanning of a 31-mm x 34-mm region of interest • over 40,000 digitized surface points • Talar joint surface • intact articular cartilage (Atc) • subchondral bone surface (Atb)

6. Materials and methods

7. Materials and methods • Use PV-Wave to compute cartilage thickness from Atc and Atb in three distinct approaches • a) vertical distance • b) proximity method • c) normal distance

8. Materials and methods • In addition to quantifying variances • closest approximation of the true cartilage thickness • utilized a cylindrical object with two specific radii • 25.52-mm on one side • 27.46-mm on the other

9. Materials and methods

10. Materials and methods • Defined thickness T=1.94-mm • idealized constant cartilage thickness distribution

11. Outline • Introduction • Materials and methods • Result • Discussion

12. Result • Cartilage thickness variances • depicted as a grey-scale image

13. Result

14. Result

15. Outline • Introduction • Materials and methods • Result • Discussion

16. Discussion • The other two methods • based on magnetic resonance imaging • based on stereophotogrammetry

17. End