| Objective Anterior cruciate ligament is an important part of the knee. With the development of sport utilities and transportation industries, the ACL injury was more and more common. Arthroscopic ligament reconstruction is currently the gold standard for treatment of its injury. Select reconstruction materials has been an important factor affecting prognosis. Based on the traditional choice of autograft and allograft, recently the surgical procedure using auto-allo-graft as materials has been appeared. The objective of this research was to provide a theoretical basis for the clinical using of auto-allo-graft, through investigating the histological process of the healing of tendonbone interface, compared with autograft, allograft and auto-allo-graft.Methods 45 healthy adult New Zealand rabbits were involved, and divided into autoallo-graft, allograft and autograft group in average. The tendon harvested from extensori digitorum longi(EDL) tendon of auto-allo-graft group rabbits' left knees and allograft group rabbits' bilateral knees rinsed clean with physiological saline before put them into the cryopreserved tubes of 15% dimethyl sulfoxide(DMSO) solution. Firstly,placed the tubes in ordinary refrigerator(4?) after 30 min in deep cryogenic refrigerator(-20?) 30 min, lastly in-80? for 2 weeks. The tubes, took out after 2weeks, put in the water bath box(37?) to thaw quickly, then took the tendon in physiological saline containing gentamicin. A double strand of EDL combined random were transplanted to reconstract the anterior cruciate ligament(ACL) on the right knee joint of the allograft and auto-allo-graft group, while their own ACL was resected. The autograft group, harvested their bilateral EDL to reconstract the ACL after double strand woven. At 3, 8 and 12 weeks postoperatively, random executed 5 rabbits in each group respectively, took the right knee joints, placed in 10% formalin solution. After48 hours, using bone saw to make the femoral and tibial tunnel of the graft into thin bone blocks, then put into 10% nitric acid solution to decalcify for 3 days, at last made them into paraffin section. Using hemaetoxylin-eosin(HE) staining and Toluidine Blue staining to observe the healing of the bone-tendon interface in each time point after reconstruction and count the new cartilage cells through the IPP software.Results At the 3th week postoperatively, the tendon-bone interface in each group showed obviously tissue necrosis, a small amount of inflammatory cells infiltration and disordered arrangement of collagen fibers. At 8th week, three groups tendon-bone interface were seen a lot of new tissue cells, collagen fibers longitudinally tend to be more orderly and toluidine blue staining negative material not observed. At 12 th week,the collagen fibers hyperplasia in great quantities, in the tendon-bone interface appeared typical 4 layer structure. The collagen fibers of autograft group were arranged more orderly and the 4 layer of the tendon-bone interface were more clearly.There was a tidemark line between fibrocartilage and mineralized fibrocartilage, but allograft and auto-allo-graft group could not be seen. Through toluidine blue staining under the microscope postoperatively, the number of cartilage cells in the tendon-bone interface was autograft group>auto-allo-graft group>allograft group.Conclusion At the same time point after ACL reconstruction, the healing of tendonbone interface of autograft was the best, and auto-allo-graft was between autograft and allograft, and the process of the histological healing was good. The result was to provide a theoretical basis for the clinical using of auto-allo-graft to reconstruct the injury ACL. |
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