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Team LEGS

The Effect of Tensile Strength Loss on Collagen Organization in Anterior Cruciate Ligament Grafts Post-Reconstruction Surgery. Team LEGS. ACL Injuries. http://www.youcanbefit.com/images/ACL%20tear.bmp. ACL Reconstruction.

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Team LEGS

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  1. The Effect of Tensile Strength Loss on Collagen Organization in Anterior Cruciate Ligament Grafts Post-Reconstruction Surgery Team LEGS

  2. ACL Injuries http://www.youcanbefit.com/images/ACL%20tear.bmp

  3. ACL Reconstruction • In 2000, over 2 billion dollars were spent on about 175, 000 ACL reconstructions (Spindler and Wright, 2008) • No consensus among surgeons on the ideal surgical/graft choices, fixation methods, etc. • 3 Common Graft Types

  4. ACL Allograft http://www.aclsolutions.com/images/Seif_what%20is%20ACL.jpg

  5. Patellar Tendon Graft http://www.aclsolutions.com/images/Seif_patellar%20tendon%20graft.jpg

  6. Hamstring Graft http://www.aclsolutions.com/images/Seif_hamstring%20graft.jpg

  7. Previous Studies • Graft degradation – tension loss in the long-run after surgery (Arnold et al., 2005) • Graft tension directly related to laxity of the knee (Friedrich et al., 1998) • Crimping patterns of other tendon and ligaments as related to short term mechanical stress (Franchi et al., 2009)

  8. Uniqueness of Project • This study will analyze: • Three graft types • Performance of grafts under long term mechanical loading • Relation of performance to collagen fiber morphology using Optical Coherence Tomography (OCT)

  9. Passive Knee Motion http://img.alibaba.com/photo/106928473/CONTINUOUS_PASSIVE_MOTION_equipment.jpg Continuous passive knee motion emulator

  10. Research Questions • How does the rate of tension loss differ among commonly used grafts during and after CPM? • How do the differing morphologies of these graft tissues relate to their variable biomechanical performance?

  11. Hypotheses • Different grafts will have different rates of tension loss during CPM • The microstructural organization of collagen is related to the rates of tension loss among the grafts

  12. Collagen Crimping

  13. Methodology Overview • Experimental Set-up • Specimen Preparation • Experimental Groups • Pre-Test Imaging • OCT • PLM • ACL Reconstruction • Tension transducer • CPM • Post-Test Imaging

  14. Experimental Set-Up • 5 pairs of knees • Experimental Groups • Control • Experimental • Specimen Preparation • Harvest grafts • Storage

  15. Pre-Test Imaging • Optical Coherence Tomography (OCT) • “optical ultrasound” • Instant, direct; no sample preparation • Polarized Light Microscopy (PLM) • Transmit visible light through sample • Tissue fixation

  16. Pre-Test Imaging • PLM • Crimp angle • Crimp arc-length • Crimp base length • OCT • Crimp period

  17. CPM • 200N • 1500 cycles mts.com

  18. Post-Test Imaging • OCT • Crimp period • PLM • Crimp angle • Crimp arc-length • Crimp base length

  19. Acknowledgments • Dr. Adam Hsieh • Hyunchul Kim • Dr. Yu Chen • Thomas Harrod • Rebecca Thomas • Courtenay Barrett

  20. Timeline: Successes • Received $1500 from HHMI Undergraduate Research Fellowship • Contacted Maryland State Anatomy Board for specimen • Obtained lab & storage space • Obtained Imaging Equipment • Obtained testing equipment • Contacted orthopedic surgeon • Wrote thesis proposal

  21. Timeline: Sophomore Year • Contact more experts, particularly surgeons • Continue to collect/review relevant literature/articles for final thesis • Apply to more grants (NSF, ACCIAC) • Design team website • Start training for lab techniques: histology, cutting tissue, MTS testing

  22. Timeline: Junior Year • Data collection • Present research/progress at the fall Colloquium • Present poster at the spring Undergraduate Research Day • Develop an outline for the final thesis and complete the first 3 chapters (Introduction, Literature Review, Methodology) • Continue to review literature • Apply to more grants • Submit paper for journal publication if possible • Update website as needed

  23. Timeline: Senior Year • Finish data collection and analysis • Complete senior thesis • Confirm at least 5 experts to sit on the panel of reviewers/discussants • Present and defend team thesis at the Team Thesis Conference • Final updates for website

  24. Timeline: Senior Year • Finish data collection and analysis • Complete senior thesis • Confirm at least 5 experts to sit on the panel of reviewers/discussants • Present and defend team thesis at the Team Thesis Conference

  25. Questions?

  26. References • Arnold, M. R., Lie, D. T. T., Verdonschot, N., de Graaf, R., Amis, A. A., & van Kampen, A. (2005). The remains of anterior cruciate ligament graft tension after cyclic knee motion. American Journal of Sports Medicine, 33(4), 536-542. • Franchi, M., Quaranta, M., Macciocca, M., De Pasquale, V., Ottani, V., & Ruggeri, A. (2009). Structure relates to elastic recoil and functional role in quadriceps tendon and patellar ligament. Micron, 40(3), 370-377. • Friederich, N. F., & O'Brien, W. R. (1998). Anterior cruciate ligament graft tensioning versus knee stability. Knee Surgery, Sports Traumatology, Arthroscopy, 6(1), S38-S42.

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