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

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Presentation on theme: "The Effect of Tensile Strength Loss on Collagen Organization in Anterior Cruciate Ligament Grafts Post-Reconstruction Surgery Team LEGS."— Presentation transcript:

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

2 ACL Injuries

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

4 ACL Allograft

5 Patellar Tendon Graft

6 Hamstring Graft

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

8 Uniqueness of Project o 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 Continuous passive knee motion emulator

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

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

12 Collagen Crimping

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

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

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

16 Pre-Test Imaging o PLM  Crimp angle  Crimp arc-length  Crimp base length o OCT  Crimp period

17 CPM mts.com o 200N o 1500 cycles

18 Post-Test Imaging o OCT  Crimp period o PLM  Crimp angle  Crimp arc-length  Crimp base length

19 Acknowledgments o Dr. Adam Hsieh o Hyunchul Kim o Dr. Yu Chen o Thomas Harrod o Rebecca Thomas o 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 o 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), o 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), o 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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