| Objective: To explore the histological and biomechanical effects of tendon repair tension of different sizes on rotator cuff injury repair in rabbits,so as to provide certain experimental basis for the treatment of rotator cuff injury and postoperative rehabilitation.Methods: Forty New Zealand white rabbits were randomly numbered and divided into four groups: control group,normal tension group,low tension group and high tension group.Among them,7 rabbits were selected as the control group and the remaining 33 as the experimental group and were divided into three groups: normal tension group,low tension group and high tension group.Bilateral shoulder joint experiments were carried out in the three groups of experimental rabbits.The rotator cuff fracture model was established and the tendon repair tension of different sizes was treated.In the first step,bilateral supraspinatus tendon detachment was performed on the experimental rabbits,resulting in acute rotator cuff tear.Acute resection of the detached supraspinatus tendon at the free end of 0.5cm and 1.0cm was performed in the low-tension group and the high-tension group,respectively.In the second step,the tendons of the three groups of experimental rabbits were pulled back to the original insertion point,and the tension was measured and recorded with a specific tension meter.The third step was to suture and fix the tendon in situ insertion(bone tunnelling method + improvedmason-allen technology),and establish a rabbit rotator cuff model with different repair tension.In the control group,5 rabbits were examined by mechanics and 2 were observed by tissue structure,which were used as normal controls.The normal tension group,the low tension group and the high tension group were randomly selected from 2 rabbits for tissue observation at the end of 2,4 and 8 weeks after surgery,respectively.The remaining 5 rabbits in each group were examined by biomechanics at the end of 8 weeks after surgery.Results: The experimental rabbits included in the results were all successfully sampled after surgery,with good wound healing and no adverse reactions such as exudation and infection.(1)Histological observation results: 2 weeks after the operation,the fractures at the sutures of suprapasal tendon insertion in the normal tension group,the low tension group and the high tension group were all visible,and the interface of the tendon and bone was filled with granulation tissue and inflammatory cells,among which a small number of fibroblasts were occasionally seen in the low tension group and the normal tension group.Four weeks after the operation,the inflammatory response of the tendon and bone specimens in the normal tension group,the high tension group and the low tension group was reduced.The gap at the suture junction of tendon and bone interface decreased,and the gap was slightly more obvious in the high-tension group,with more granulation tissue growingin.Hyperplasia of chondrocytes was observed in the low-tension group and the normal tension group.A small number of fibroblasts grew and part of uncalcified fibrous cartilage grew into the tendon.Penetration of tendon and bone tissue in both groups was predominant in the low-tension group.At 8 weeks after the operation,the tendon and bone junctions in the normal tension group,the high tension group and the low tension group were all denser than before;no obvious chondrocytes and fibroblasts were seen in the high tension group compared with the low tension group and the normal tension group,and the tendon and bone interfaces were connected by fibrous scar tissue.Chondrocytes and fibroblasts were formed in the low tension group and the normal tension group,while dense Sharpey fibers were formed in the low tension group and the normal tension group,which were arranged in a neat and consistent manner and preliminarily formed a new subganglionic stop,which was more obvious in the low tension group than in the normal tension group.(2)Biomechanical test results: The tendon repair tension in the surgery group increased significantly with the increase in the length of the excised tendon,and the difference was statistically significant(P <0.05).At 8 weeks after the operation,pairwise comparison showed that the maximum load of normal tension group,high tension group and low tension group was lower than that of the control group,and the difference was statistically significant(P < 0.05).The maximum load of thelow-tension group was greater than that of the high-tension group,with statistically significant difference(P < 0.05).Conclusion: In acute rotator cuff injury in rabbits,low repair tension may promote the healing of the rotator cuff tendon-bone interface to some extent. |
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