| Objective: Articular cartilage injury was a common clinical knee disease. Sports injuries, obesity, and age were important factors in the occurrence and progression of it. However, since there were no blood vessels and nerves in the cartilage, it was difficult to recover once the injury happened. After the cartilage was injured, the injury would aggravate by the following ways, on the one hand, the lack of adequate stress of the tibiofemoral joint made the injured area not be allocated appropriate force and absorb nutrients normally, leading to stress redistribution, cell function decreased, on the other hand: mucin glycan escaped from the tissue, resulting in changes in cartilage stiffness, increasing the risk of cartilage damage, and these risks would happen in normal articular bearing activities. Because the biomechanical properties of the cartilage obviously were depended on its composition and normal ultrastructure, the biomechanical measurement was an intuitive reflection of the mechanical properties of the degree of the cartilage repair. Therefore, compared with the histology characteristics of cartilage, the recovery of its biomechanical properties was also very important The treatment of articular cartilage injury could be divided into two categories based on whether repairing the cartilage or not currently. First: oral medicine could block the inflammatory progress to ease the pain, it had little effect on cartilage repair. Second: Cartilage could be repaired in many ways: cartilage, periosteal transplantation techniques and gene therapy were proven to promote cartilage regeneration, but the complexity and high cost of the operation made them difficult to carry out in clinic extensively; in clinical work, microfracture technique and platelet-rich plasma stimulated the bonemarrow mesenchymal stem cells differentiate into cartilage cells and repaired cartilage defects ultimately, or promoted healing of injured tissues by cell activation and proliferation through the concentration of growth factors. But at present, a lot of research had focused on the histological observation of cartilage damage of a single or combined treatment. Microfracture technology and platelet rich plasma can provided seed cells and growth factors similar with tissue engineering, the operation was simple, convenient extraction and the combined treatment of cartilage damage with these two methods were convenient for clinical operation. This study was designed to compare biomechanical changes of the repaired cartilage of full-thickness defect in different methods and to explore the effect of microfracture technology combined with platelet-rich plasma for treatment of articular cartilage defects, and to provide a theoretical basis and guidance for clinic.Methods:A total of 20 male New Zealand white rabbits were random divide into four groups, and there were 5 in each group(A, B, C and D). Vein blood was drawn in the rabbit ears in B, D groups and platelet-rich plasma was prepared by centrifugated twice. The blood cell analyzer was used for PRP platelet count, and activated by calcium chloride and bovine thrombin. Left knee joints were left as blank control. Full-thickness cartilage defect models were manufactured in the weight-bearing area of the medial femoral condyle of the knee. Group A: make full-thickness cartilage defect model, no treatment for the cartilage defects; Group B: make full-thickness cartilage defect model, activated platelet-rich plasma was injected into the knee; Group C: make full-thickness cartilage defect model, processing microfracture surgery in cartilage defect area; Group D: make full-thickness cartilage defect model, processing microfracture surgery in cartilage defect area and injecting activated platelet-rich plasma into the knee. After 12 weeks, all rabbits were executed in each group, five left randomly selected knee and all right knee were used for general observation and biomechanical experiments in use of prescale pressure-sensitive paper by measuring the articular surface contactarea and pressure.Results: 1 General observation: after 12 weeks, A group: Cartilage defect was only filled by a thin layer of fibrous scar with dark red surface, the cartilage defects was obvious and the boundary between the defect area and normal cartilage was clearly visible; Group B: there was grey cartilage tissue in the cartilage defect area, but it was uneven, and there was clear boundaries between repaired area and surrounding normal cartilage; Group C: there was flat grey cartilage tissue in the cartilage defect area, but its surface is rough, and there was clear boundaries between repaired area and surrounding normal cartilage; D Group: there was flat white cartilage tissue in the cartilage defect area, its surface is smooth and glossy, there were fuzzy boundaries between repaired area and surrounding normal cartilage their colour and lustre were similar. 2 Biomechanics, after twelve weeks, the difference between the contact area and pressure of the medial and lateral sides of the right tibiofemoral joint of group A and group B,C,D and the control group was statistically significant(P<0.05), the difference between the contact area of the medial and lateral sides of the right tibiofemoral joint of group B,C and group D, the control group was statistically significant(P<0.05), the difference between the pressure of the medial and lateral sides of the right tibiofemoral joint of group B,C and group D, the control group was not statistically significant(P>0.05), the difference between the contact area and pressure of the medial and lateral sides of the right tibiofemoral joint of group D and the control group was not statistically significant(P>0.05).Conclusion: Microfracture technique, platelet-rich plasma, or a combination of both could promote full-thickness cartilage defects repair. A combination of microfracture technique, platelet-rich plasma acquireed better histological and biomechanical properties and Integrity at 12 weeks. Microfracture technique combined with platelet-rich plasma is an effective method for the treatment offull-thickness cartilage defects and maintain its biomechanical properties. |
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