The Research Of Anterior Cruciate Ligament Reconstruction In Rabbits Using Autogenous Tendon Combined With Allogeneic Tendon

Objective:To investigate the biomechanical change and histological rejection after ACL reconstruction in the rabbits using autogenous tendon combined with allogeneic tendon versus autogenous tendon.Methods:Twenty-four healthy female adult New Zealand white rabbits,weighting 2.2～3.0kg, ACL in rabbits was cuted and removed completely to build a anterior cruciate ligament reconstruction model,One-side knee joint reconstructed with autogenous-allogeneic tendon was selected randomly as the test, and the other joint reconstructed with autogenous tendon folded double was served as the control at the same time.At 3,6 and 10 weeks after operation,models (8 animals) were harvested randomly in deep general anesthesia, five of them do biomechanical test,the other 3 were to observe the gross observation, histological determination at the differet period of ACL reconstruction in rabbits.Results:① At the third weeks of ACL reconstruction in rabbits,there was a clear boundary between autogenous tendon and allogeneic tendon in the text group.The unioned grafts were infiltrated by small inflammatory cells, the cells of reconstructed grafts disappeared and showed necrosis,the peripheral of grafts in the group covered litter synovial tissue、fibroblasts and new blood vessels,which were growing from the edge to the center.The tendon-bone interface was connected loosely with granulation tissue,can observe less new blood vessels.The grafts in the control group exhibited mild loose or disfiguration,their boundary was clear, the peripheral of grafts in the group covered litter synovial tissue and fibroblasts,no less blood vessels grow into.② At the sixth weeks of reconstruction,the unioned grafts were covered by the synovial tissue and the infiltrative inflammatory cells disappeared,the synovial tissue inside was significant,e hyperplastic cells and new blood vessels remarkably trended to the center.The tendon-bone interface was connected tightly,the number of newborn bones was large and their arrangement was relatively regular,. The Sharpey’s fiber was seen between the tendon graft and the bone tunnel,which was similar to normal tendon-bone interface.The number of fibroblasts in the control group increase rapidly and the center of grafts was still in a few cell state.Partial bone formation was seen between the tendon graft and the bone tunnel in the control group, with disorderly arrangement, and there were many collagen fibrous joints between the tendon graft and the bone tunnel.③At the tenth weeks of reconstruction.the inflammatory cells of grafts disappeared, with contact surface fusion,the peripheral and central of grafts in the text group had a number of flbroblasts formation,the tendon-bone interface appear Sharpey’s fiber formation,and some chondrocytes.The contact surface between grafts in the control group mostly disappeared,with a litter gap.A large number of fibroblasts appeared in the peripheral of grafts,and fibroblasts also appeared in the center.The tendon-bone interface was connected tightly,the number of newborn bones was large and their arrangement was relatively disorder,the Sharpey’s fiber was seen between the tendon graft and the bone tunnel.④ 3、6 and 10 weeks after operation, the pullout or pull and break loads of the experimental group were 36.406 N/cm,42.802 N/cm,71.51 N/cm respectively, and those of the control group were 25.616 N/cm,31.044 N/cm,61.608 N/cm respectively. There was significant difference between the two groups (P<0.05).Conclusions:Conpared with anterior cruciate ligament reconstruction in rabbits using autogenous tendon,the use of autogenous tendon combined with allogeneic tendon may promote graft maturation rate and the strength of graft,shorten the time of osteogenesis between the tendon graft and the bone tunnel, improve healing strength.