الفهرس 
ContentsOnly 14 pages are availabe for public view
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Abstract
A randomized controlled study was performed on 18 male donkeys where SDFT tenetomy and tenorrhaphy was performed leaving a cm full thickness gap to investigate the role of platelet rich fibrin and chitosan on the healing of the severed SDFT. According to the bioscaffolds, animals were randomly divided into 3 groups (6 each) : Control group, (tendon gap was left for healing without addition of biomaterials), PRF group, and PRF/Chitosan group. The healing capacity of the severed tendons between the groups was evaluated by ultrasonographic examination at 2 weeks interval till 3months and by clinical, gross and histopathological examination on the 45th and the 90th day postoperative. Ultrasonographic examination of repaired SDFT in PRF and PRF/Ch groups showed early and nearly restoring of the ultrasonographic picture of the normal SDFT versus abnormal ultrasonographic picture with irregular shaped scar tissue in the control group. Additionally, the clinical examination revealed normal clinical index scores in PRF and PRF/Ch groups where neither swelling, nor pain and lameness with a comfortable attitude was observed compared to the control group. Additionally, histopathological findings confirmed regeneration of the SDFT of the PRF group which revealed healing of tendon tissue with nearly well-organized collagen bundles and lower inflammatory cell infiltration and neovascularization at the end of study compared to the control group. Moreover, the PRF/Ch group showed a significant well-organized normal collagen bundle with few inflammatory cells and neovascularization compared to the PRF group. Conclusion: Healing of a cm gap tenorrhaphy in control group is characterized by abnormal thick scar tissue formation with marked adhesion, inflammation and accompanied with severe lameness and pain. The use of PRF in gap tenorrhaphy stimulates tendon regeneration and restores the normal tendon histo-architecture and biomechanical function. The addition of chitosan to PRF clots potentiates its effect and greatly enhances and accelerates SDFT regeneration expressed by better and faster reduction in SDFT thickness, lower peritendinous adhesion, lower intratendinous edema, lower inflammation, better fiber arrangements score and better total histological score.