| Objective: Rotator cuff tear is one of the most common causes of shoulder joint pain.Although great progress has been made in surgical repair technology,the re tear rate after rotator cuff repair and fixation is still very high,but the healing intensity of tendon bone interface is not.It is mainly scar healing,which can not achieve real tendon-bone healing.In order to explore effective methods to promotetendon-bone healing,It is proposed to improve the treatment method of rotator cuff insertion point interface,improve the suture fixation method and combine with tissue engineering scaffolds to better improve the tendon bone healing rate of tendon bone interface after rotator cuff injury,improve the healing strength of tendon bone interface,promote rapid functional recovery and further improve the clinical curative effect.method:128 healthy New Zealand white rabbits weighing 2.4Kg-3.0Kg were randomly divided into four groups: blank group(n=32),normal New Zealand white rabbits without supraspinatus muscle transection;Foot print area freshening repair group(n=32): after the successful modeling of rotator cuff injury,the foot print area of supraspinatus muscle was freshened,the cortical bone on the surface of the interface of supraspinatus tendon was removed with orthopaedic grinding drill,the supraspinatus tendon was repaired with mattress suture with full suture anchor,and the tail end of suture was sutured and fixed through bone canal;Half bone canal repair group in footprint area(n=32): after the successful modeling of rotator cuff injury,the bone tunnel was established in the footprint area of supraspinatus muscle with orthopaedic grinding drill,forming a semi bone tunnel with a length of 10 mm * width 4mm * depth 2mm cube,and the supraspinatus tendon was repaired by mattress suture with full suture anchor,and the tail end of the suture was sutured and fixed through the bone tunnel;In the footprint area,the semi bone tunnel combined stent repairment group(n=32): on the basis of the half bone repair group in the foot print area,after implantation of the full suture anchor,the Graphene oxide(GO)combined with platelet rich plasma(Platelet-rich plasma,PRP)hydrogel stent was added into the semi bone tunnel to promote the repair of 0.5mg/ml.MRI was performed at 4 and 8 weeks after operation to evaluate the healing of supraspinatus tendon bone interface;CT was performed to evaluate the growth of new bone at the tendon bone interface;Biomechanical examination was performed to evaluate the strength of tendon bone healing;The healing of tendon bone interface was evaluated by gross observation and histopathological sections(HE staining and Masson staining).result: Four weeks after operation,no obvious scar tissue,abscess or inflammatory granulation tissue was found in the shoulder joint of each group.The connective tissue around the footprints was slightly disordered,and the tendon bone interface and bone groove filling were basically complete.In the freshening repair group,the muscles around the shoulder joint were slightly atrophied,and the tendon was thinner than the other three groups,There was no significant difference between the half bone canal repair group and the half bone canal combined with stent repair group;At 8 weeks after operation,the tendon bone connection in the footprint area of each group was more compact than that at 4 weeks,the muscles were plump,and the tendon bone interface and the semi bone tunnel were filled completely.Among them,the tendon bone healing was the most compact,the surrounding connective tissue was arranged the most tightly,and the tendon bone interface was fully fused in the semi bone tunnel combined with stent repair group).The CT results at 4 and 8 weeks after operation showed that the semi bone tunnel combined with stent repair group in the footprint area had earlier new bone formation at the edge of the bone bed at the tendon bone insertion point,and the bone density was higher,which was evenly distributed in the whole area of the bone bed.The appearance of new bone was significantly more than that in the other two groups,and the semi bone tunnel repair in the footprint area was better than the fresh repair in the footprint area.):The MRI results at 4 and 8 weeks after operation showed that the supraspinatus tendon in the semi bone tunnel combined with stent repair group was more continuous,regular in shape and uniform in signal of supraspinatus muscle;In terms of biomechanics,at 4 weeks after operation,the limit loads of the blank group,the freshening group of the footprint area,the semi bone tunnel group of the footprint area and the semi bone tunnel combined stent group were 131.51±18.00 N,73.81±7.67 N,75.67±8.95 N and102.05±12.0N respectively,and the stiffness were 11.44±1.18N/mm 、8.10±0.74N/mm 、 8.77±1.15N/mm 、 10.33±1.17N/mm respectively.Among them,the blank group showed the best performance,with statistical difference compared with the comparison of each group(P<0.05).There was statistical difference between the foot print area semi bone canal combined with stent group and the foot print area semi bone canal group(P<0.05).There was no statistical difference between the foot print area fresh group and the foot print area semi bone canal group(P>0.05).At 8 weeks after operation,the limit loads of blank group,fresh footprints group,semi bone tunnel group and semi bone tunnel combined stent group were 139.74±13.98 N,98.36±8.78 N and110.09±11.67 N respectively;132.62±9.78 N,and the stiffness were14.75±1.62N/mm 、 9.85±0.53N/mm 、 11.54±1.42N/mm 、 13.11±1.90N/mm respectively,except that the blank group was significantly improved 4 weeks after operation,The blank group and the semi bone tunnel combined stent group in the footprint area were significantly higher than those in the freshness group and the semiosseous canal group in the footprint area(P<0.05).There was no significant difference between the blank group and the semi bone tunnel combined stent group in the footprint area.The semi bone tunnel group in the footprint area was better than the freshness group in the footprint area(P<0.05),and the semi bone tunnel stent group was better than the experimental group(P<0.05);In terms of histological staining,at 4 and 8 weeks after operation,the blank group and the combined scaffold group of the semi bone tunnel in the footprints were better than the freshening group and the semi bone tunnel group in the footprints,and the semi bone tunnel group in the footprints was better than the freshening group in the footprints.At the same time,collagen fibers with regular arrangement were densely distributed at the tendon bone interface in the semi bone canal scaffold group.The growth of Sharpey fibers and the number of chondrocytes were the most abundant,the morphology was close to normal tendon cells,and the amount of mature bone increased significantly.Conclusion:1.The semi bone tunnel with total stitching anchor double row fixed repair technology can increase the fixation strength,reduce the risk of pull out the anchor,increase the contact area and contact pressure between the rotator cuff tissue and the foot print area,and provide a more reliable attachment part for the hydrogel scaffold,which is conducive to the slow,sustained and precise release of growth factors.2.the semi-bone suture anchor double row fixed repair technology combined with GO-PRP hydrogel scaffold can effectively promote the ability of osteogenesis,cartilage formation and tendon formation at the tendon bone interface,improve the strength and stiffness of the tendon bone transitional zone,improve the biomechanical properties of the tendon bone transitional zone,and promote the healing of the tendon bone interface of rotator cuff injury.In order to lay a theoretical foundation for the rapid rehabilitation of shoulder joint function after rotator cuff injury. |
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