| Purposes1.To evaluate the feasibility of different animal models of rotator cuff injury for exploring the effect of autologous osteochondral joint periosteum on tendon-bone healing of rotator cuff injury,in order to select the most suitable animal model.2.To evaluate and compare the effect of different interventions on tendon-bone healing of rotator cuff injury by autologous osteochondral joint periosteum,autologous osteochondral,autologous periosteum and simple suture at overall,histological and biomechanical levels.Methods1.Select animal models: dissect and observe the rotator cuff morphology of mice,rats and rabbits to select suitable rotator cuff injury models;measure the non-weight-bearing area of the knee joint and the proximal medial tibial area of different animals to assess their feasibility;make acute and chronic rotator cuff injury models and compare their repair differences.2.To construct a model of acute supraspinatus tendon injury in rabbits: find the stopping point of supraspinatus tendon,sharply cut the tendon from the attachment point of supraspinatus tendon at the greater tuberosity of the humerus,and remove the cortical bone layer and polish it to the cancellous bone layer.3.Graft extraction and surgical protocol: The osteochondral column was prepared with a hollow drill in the non-weight-bearing area of the non-identical knee joint,and the osteochondral membrane was prepared and marked on the proximal medial side of the non-identical tibia.In the control group,the supraspinatus tendon repair was performed;in the osteochondral group,the osteochondral column was grafted to the supraspinatus tendon stop and the supraspinatus tendon repair was performed;in the periosteal group,the periosteum was sutured to the supraspinatus tendon stop and the supraspinatus tendon repair was performed;in the osteochondral combined with periosteum group,the osteochondral column and periosteum were grafted to the supraspinatus tendon stop and the supraspinatus tendon repair was performed.4.Efficacy assessment: The animals and the humeral-supraspinatus tendon complex were observed postoperatively at 4W,8W and 12W（activity,tendon-bone healing and infection）,stained（HE staining,Masson staining,red-solid green staining）and biomechanically measured（supraspinatus tendon cross-sectional area,maximum tensile strength,stiffness）.Results1.Results of animal model experiments:（1）The rotator cuff structure of mice is significantly smaller than that of rats and rabbits,which makes it difficult to operate and not suitable for surgical intervention;the rotator cuff structure of rats is larger than that of mice,which makes surgical intervention feasible,but its structure is smaller than that of rabbits,and the subacromial muscle is the supraspinatus muscle rather than tendon tissue;（2）The supraspinatus tendon is located in a shallow attachment point with a large area and width,which makes it more suitable for surgical The area of the non-weight-bearing area of the distal femur and proximal tibia of the rabbit knee is larger,and the osteochondral column and periosteum are more feasible to take;（3）the retraction of the injured supraspinatus tendon increases over time,making surgery more difficult and prone to failure,so an acute injury model is preferred.2.Histological results:（1）At 4W after surgery,HE staining showed that the tendon-bone gap was larger in all groups,and a large number of inflammatory cells were seen in the tendon-bone gap,and the tendon-bone gap in the autologous osteochondral joint periosteum group was smaller than that in the other groups;Masson staining showed that a small number of collagen fibers were produced in each group,and the arrangement was disorganized;fuchsin-fixed green staining showed that more chondrocytes were produced in the osteochondral joint periosteum group,but not in the other groups.（2）At 8W after surgery,HE staining showed that the tendon-bone gap was smaller in each group than before,and the tendon-bone gap was smaller in each experimental group than in the control group,and local chondrocyte production was seen in the experimental group.（3）12W after surgery,HE staining showed that the control group had loose and disordered Sharpey fibres at the tendon-bone interface,while the experimental groups showed tidal lines and dense Sharpey fibres,with the osteochondral joint periosteum group showing a typical tendon-bone migration structure;Masson staining showed that the collagen fibres in each group were produced more and arranged more neatly than before In the osteochondral joint periosteum group,the collagen fibres were arranged in a directional manner and the structure was more complete;the chondrocyte production in each group increased compared to the previous one,and the osteochondral joint periosteum group had the largest area of heterostaining and produced the most cartilage.3.Biomechanical results: The cross-sectional area,maximum tensile strength and stiffness of supraspinatus tendon in each group tended to increase over time,and there was no significant difference in the cross-sectional area and stiffness of supraspinatus tendon in each group at 4W after surgery.Conclusions1.The rabbit acute supraspinatus tendon injury model can be used as a suitable animal model for autologous osteochondral combined with periosteal intervention.2.Autologous osteochondral joint periosteal grafting can effectively promote the regeneration of fibrocartilage at the tendon-bone union of rotator cuff,thus facilitating tendon-bone healing,which is an effective treatment strategy for tendon-bone healing of rotator cuff injury. |
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