| Objective: To observe the healing process between anterior horn of medial meniscus and bone after transtibial pull-out surgical technique(TP),and the role of platelet-rich plasma(PRP)in the healing process of anterior horn of meniscus and bone wall in rabbits.Methods: Seventy New Zealand rabbits were used as the normal group,and seven rabbits were used as the normal group to compare the difference in maximum tensile rupture strength of the anterior root of the medial meniscus in double lambs.The remaining experimental animals were randomly divided into three groups.They were medial meniscus anterior horn tear group(group A),medial meniscus anterior horn rupture + surgery group(group B),and medial meniscus anterior angle tear+surgery + PRP group(group C).There were 21 rabbits in each group.Three rabbits,nine rabbits and nine rabbits were sacrificed in each group at 4 weeks(4w),8 weeks(8w)and 12 weeks(12w)respectively after surgery.Three rabbits were selected for each group at each time point for gross observation and histological staining.The remaining 6 rabbits at 8w and 12 w respectively were used in biomechanical experiments to detect the maximum tensile rupture strength of the meniscus anterior horn.Results:(1)Preparation and activation of PRP: The platelet concertration in PRP was about 4.57 times that of whole blood.Compared with PRP before activation,the concertrations of rabbit platelet-derived growth factor(PDGF)and transforming growth factor ?1(TGF-?1)in activated platelet-rich gel(PRG)were significantly increased,which were 2.46 times and 4.15 times respectively.(2)Gross observation: After cutting the anterior horn of the meniscus in group A,the position of the meniscus at each time point has a slight outward movement,and the color of the articular cartilage surface is red.At the 4 weeks after surgery,the color and morphology of meniscus meniscus in group B and group C gradually returned to normal.(3)Histological staining observation: HE staining and Masson staining showed that in group A,inflammatory cell infiltration was observed at the anterior horn of the broken meniscus,and the collagen fibers were disorderly arranged.In group B,the fibroblasts at the junction of the meniscus anterior horn and the bone tunnel began to increase at 4w after TP.At 8w,the collagen fibers increased and arranged neatly.At 12 w,bone-like tissue appeared in the bone tunnel,and the collagen fibers that connect the anterior horn and the bone wall of the meniscus are denser.The histological appearance of group C animals with PRP in the bone marrow tract was similar to that of group B,but the healing rate was significantly accelerated.(4)Biomechanical results showed that there was no significant difference in the maximum tensile rupture strength between the medial meniscus of the left knee and the right knee of normal rabbits.Compared with the A group at the same time,the maximum tensile rupture strength of group B and group C increased significantly after 8weeks and 12 weeks,and the strength of group B and group C was 1.46 times and 2.07 times of group A after 8weeks(P<0.01).At 12 w postoperatively,the maximum tensile rupture strength of group B and group C was 2.10 times and 2.72 times of group A(P<0.01).At 8w after operation,the maximum tensile rupture strength of the medial meniscus in group C increased significantly,which was 41.58% higher than that in group B(P<0.05).At 12 w after surgery,the maximum tensile rupture strength of group C increased compared with group B,but there was no significant difference.In group C,at 8w and 12 w after surgery,the meniscus intensity reached 25.14% and 38.31% of normal meniscus intensity.There was no significant difference in the maximum tensile rupture strength of meniscus in group A between 8w and 12 w after surgery.With the prolongation of postoperative time,the mechanical strength of 12 w both in group B and group C showed greater than the intensity of the 8w,which increased by 65.97% and 52.4%(P<0.01).Conclusions: The medial meniscus anterior horn injury can be repaired by the transtibial pull-out surgical technique.Autologous platelet-rich plasma added to the bone marrow can promote early healing of the meniscus and bone after surgery. |
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