In conclusion, the present study firstly addressed the relationship between graft incorporation and peri-graft bone quality and quantity after ACL reconstruction in a rabbit model. The findings suggested that the non-invasive measurement of peri-graft bone would be useful to predict graft incorporation. Peri-graft bone loss was region-specific after surgery, which might be associated with stress shielding in the specific region after tunnel creation. The use of Brushite CPC might be a promising way to augment peri-graft bone and enhance graft incorporation. (Abstract shortened by UMI.) / In the fourth part, brushite CPC was successfully applied to augment the peri-tendon bone volume and connectivity. It was revealed under mechanical testing that the ultimate strength and stiffness of graft fixation in bone tunnel on experimental side was higher than that of the control by 117% and 102% respectively at 6 weeks, postoperatively (p<0.05 for both). The use of brushite CPC caused a paradigm shift in failure mode from intra-tunnel to intra-articular portion at 12 weeks postoperatively (p=0.013). / Keywords. anterior cruciate ligament reconstruction, bone mass, microarchitecture, tendon-to-bone healing, graft incorporation, brushite calcium phosphate cement / The first part of this thesis compared the histological characteristics of T-B healing interface tissue in femoral and tibial tunnels following ACL reconstruction in rabbits. Results revealed that less cartilaginous interface tissue was formed in tibial tunnel than in femoral tunnel. Such cartilaginous tissue was gradually mineralized during reestablishment of a direct T-B integration. T-B healing in tibial tunnel was inferior to that in femoral tunnel. The disparity of T-B healing in various osseous milieus suggested the potential association in between. / The second part of this original work further explored the numeric relationship between the strength of T-B attachment and peri-graft bone mass and connectivity. Results of Micro-computed tomography (micro-CT) showed that peri-graft bone mass and connectivity was significantly lower on tibial side than those on femoral side. It was found under biomechanical evaluation that grafted tendon was prone to be pulled out from tibial tunnel with the bone attachment; the weakest point of the complexes shifted from the healing interface at time zero to peri-graft bone at week 6 after operation. With reverse of peri-graft bone at week 12 postoperatively, the weakest point shifted to intra-osseous tendinous portion. The stiffness of graft fixation correlated with peri-graft BV/TV (r2=0.68, p=0.001) and connectivity (r2=0.47, p=0.013) at week 6 after operation. / The third part addressed the changes of peri-graft bone in spatial and temporal manners using high resoluation multiple-slice peripheral quantitative computed tomography (pQCT) and micro-CT. Under pQCT evaluation, a decrease in BMD was present in specific regions, medial region of femoral tunnel by 26% and posterior and lateral regions of tibial tunnel by 22% and 42%, respectively at week 12 postoperatively than the baseline (p<0.05 for all). It was accompanied by a decrease in trabecular number and increase in trabecular spacing, the shift of plate-like to rod-like trabeculae and loss of anisotropy under micro-CT evaluation. It was echoed by histological findings showing increased osteoclastic activities and poor T-B healing in these specific regions. The postoperative bone loss and associated poor T-B healing was region-specific. / by Wen, Chunyi. / Adviser: Kai-ming Chan. / Source: Dissertation Abstracts International, Volume: 71-01, Section: B, page: 0217. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 148-168). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese.
| Identifer | oai:union.ndltd.org:cuhk.edu.hk/oai:cuhk-dr:cuhk_344360 |
| Date | January 2009 |
| Contributors | Wen, Chunyi., Chinese University of Hong Kong Graduate School. Division of Orthopaedics & Traumatology. |
| Source Sets | The Chinese University of Hong Kong |
| Language | English, Chinese |
| Detected Language | English |
| Type | Text, theses |
| Format | electronic resource, microform, microfiche, 1 online resource (xx, 168 leaves : ill.) |
| Rights | Use of this resource is governed by the terms and conditions of the Creative Commons “Attribution-NonCommercial-NoDerivatives 4.0 International” License (http://creativecommons.org/licenses/by-nc-nd/4.0/) |
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