| Objective To explore the healing of tendon-bone interface of anterior cruciate ligament(ACL)reconstruction with LARS new type hollow ligament combined with autologous tendon in experimental animals.The results of histopathology,imaging and biomechanics were observed to analyze the healing of the reconstructed ligament after operation,so as to provide a solid experimental data and theoretical support basis for clinical reconstruction of ACL after injury with this kind of transplantation.Methods Thirty-two adult New Zealand white rabbits,aged 3 months,weighing 3-3.5 kg,half male and half female,were randomly divided into two groups,16 in the experimental group and 16 in the control group.All experimental animals were used to make ACL injury models by cutting off the right ACL body with a sharp knife.The experimental group used LARS new hollow artificial ligament combined with autologous tendon to reconstruct ACL.The autologous tendon used the ipsilateral extensor digitorum longus tendon.The control group used LARS artificial ligament only to reconstruct ACL.The anterior cruciate ligament(ACL)was reconstructed in both groups by compression and fixation with 304 stainless steel screw with 2.5mm diameter.The limbs were not fixed and moved freely after operation.During the maintenance of animal models,attention should be paid to the prevention of infection and single cage feeding.Eight rats were randomly selected from the experimental group and the control group at 3 and 6 months after operation,and were killed.Microcomputed tomography(Micro-CT)was performed first.Immediately after CT scan,4 samples were randomly selected for histopathological analysis,and the remaining 4 samples were biomechanically tested.Statistical analysis was made on the experimental data obtained by three different detection methods to evaluate tendon and bone healing comprehensively.Results During the experiment,one rabbit in the experimental group died of uncontrolled infection after operation,one in the control group died of uncontrolled infection,and one died of diarrhea due to digestive system diseases.The dead animal models were supplemented in time.The results of biomechanical test showed that the ultimate tensile strength and stiffness of ACL reconstructed in the experimental group at 3 and 6 months after operation were not significantly different from those of the control group(P > 0.05).Micro-CT three-dimensional reconstruction showed that there was no significant difference in bone volume fraction(BVF)between the experimental group and the control group at 3 months,but there was significant difference in BVF between the experimental group and the control group at 6 months(P < 0.05).Histopathological results showed that the autograft underwent a self-remodeling process wrapped in thehollow ligament,and gradually established a fibrous connection between the artificial ligament interface and the bone tunnel interface.The fibrous tissue in the experimental group was denser than that in the control group at 3 and 6 months.Conclusion 1.LARS hollow artificial ligament combined with autogenous tendon can also provide strong tensile strength of ACL compared with ACL reconstruction using artificial ligament alone,and there is no significant difference between them.2.The tendon-bone interface of ACL reconstructed by LARS hollow artificial ligament combined with autogenous tendon can form indirect healing of fibers.3.Using LARS hollow artificial ligament combined with autogenous tendon to reconstruct ACL can better prevent the widening of bone tunnel than using LARS artificial ligament alone. |
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