| Over 50,000 patients per year in the USA undergo surgical reconstruction of the ACL. There is a wide range of procedures in which the ACL has been replaced by autografts, allografts, xenografts or synthetics with variable success rates but not necessarily with normal functional restoration. Tissue engineering, an emerging field that uses combinations of resorbable scaffolds, cells and cell signals to regenerate damaged tissue, is being investigated for the regeneration of the ACL at our laboratory. Collagen fiber scaffolds have been shown to induce neoligament formation, have good biocompatibility and initial strength; however, premature resorption of the scaffold may lead to graft failure before complete regeneration.;In this thesis, we investigated the feasibility of using resorbable synthetic polymer fibers for the scaffold construct. Fibers of collagen, tyrosine-derived poly(amino-acids) and poly(L-lactic acid) were processed and characterized. Fibers that showed the most promising biocompatibility, strength retention and degradation profiles from the tyrosine-derived poly(amino-acids) and poly(L-, lactic acid) were selected for evaluation in a rabbit ACL reconstruction model previously established at our laboratory.;Unloaded in vitro characterization of the fibers were not predictable of the results found in the in vivo reconstruction model. The dynamic loading experiments suggested that loading and environment can decrease strength retention even in the absence of polymer degradation, although effects were more pronounced in vivo. Further optimization of mechanical properties of synthetic resorbable polymer fibers is necessary. In addition, a model to characterize and evaluate the fibers under loading conditions needs to be developed.;Synthetic resorbable fiber scaffolds had better mechanical survival than UV crosslinked collagen fiber scaffolds in the ACL reconstruction model. However, they did not induce tissue ingrowth. Cell seeding prior to implantation and the use of growth factors need to be explored for enhancing tissue ingrowth into the synthetic resorbable fiber scaffolds. |
