Isolated medial collateral ligament (MCL) injuries occur frequently (95,000 per year in the US) and heal with conservative treatment. Long-term clinical outcome is generally excellent because the structural properties of the Femur-MCL-Tibia complex (FMTC) naturally return to normal especially the stiffness. However, the quality of the healing ligament, as described by its histomorphological appearance, as well as biochemical, mechanical, and viscoelastic properties, remain poor [37, 70, 108, 109, 116]. Functional tissue engineering techniques such as the use of extracellular matrix (ECM) bioscaffolds have shown promise in improving healing of soft tissues after injury. In particular, small intestine submucosa (SIS) is especially attractive due to its chemoattractant properties, organized fiber alignment, and natural concentration of growth factors [9, 13, 48]. The objective of this thesis is to use SIS to improve MCL healing in a clinically relevant injury model.
Sixteen New Zealand white rabbits were subjected to a mop-end tear (Weiss et al. 1991) in order to simulate a clinically relevant injury, which included damage to the ligament insertion sites, over-stretching of collagen fibers, and a frayed appearance of the torn ligament ends. After 12 weeks of healing, seven rabbits per group were euthanized and subjected to a well-established biomechanical testing protocol [111], including a load to failure test. The remaining rabbits (n=2 per group) were evaluated histologically.
It was found that SIS treatment resulted in a marked improvement for the tangent modulus of the healing MCL midsubstance over non-treatment (404 ±120 MPa vs. 273 ± 91 MPa, respectively, p<0.05). However, this difference did not translate into a change in the measured structural properties of the FMTC. Nearly half of the specimens in each treatment group failed at the tibial insertion, this indicates asynchronous healing between the ligament insertion and midsubstance.
In conclusion, these results confirm SIS enhances the quality of the healing MCL. SIS positively effects the local healing response of an MCL regardless of injury model. This work provides a basis to explore the effect of applying SIS to ligaments which do not heal well naturally, such as the anterior cruciate ligament.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-06182007-144935 |
| Date | 25 September 2007 |
| Creators | Papas, Noah Peter |
| Contributors | Steven D. Abramowitch, Ph.D, Savio L-Y. Woo, Ph.D., D.Sc. (hon.), Steven Badylak, D.V.M., M.D., Ph.D. |
| Publisher | University of Pittsburgh |
| Source Sets | University of Pittsburgh |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.pitt.edu/ETD/available/etd-06182007-144935/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Pittsburgh or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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