Biomechanical Study Of Platelet-rich Plasma On The Repair Of Articular Cartilage Injury In The Rabbit

Objective: Knee cartilage injury can lead to knee joint cartilage obviousdegeneration, that will affect the function of knee joint seriously, thus affectthe quality of life. Although the treatment of osteoarthritis is numerous, but thearticular cartilage regeneration is weak. If you can repair the damagedcartilage will avoid joint degeneration. Cartilage injury caused thebiomechanical properties of the tibiofemoral joint abnormalities is one of theleading causes of knee joint degeneration. Micro fracture drilling operation iscurrently the most widely used operation mode. But the operation method forinvasive method, and postoperative recovery need long-term brake, preventthe new fiber cartilage loss. In recent years, many scholars have lots ofresearches in injection of platelet-rich plasma (PRP)to the knee joint afterarticular cartilage injury.The PRP include a variety of growth factors on theproliferation of chondrocyte and synthesis of extracellular matrix plays apromoting role. The repair of damaged articular cartilage of the effect ofdifferent methods was reported inconsistently. But for the biomechanical studyon the repair of articular cartilage injury with PRP is rarely reported.Thisstudy using the rabbit autologous PRP to repair the damage to the medialtibiofemoral articular cartilage.Then taking about the biomechanicscharacteristics change of the knee joint, and provides a theoretical basis andguidance for clinical.After using the rabbit autologous PRP to repair the damage to the medialtibiofemoral articular cartilage of knee joint, we measure the contact area andthe contact pressure to compare the changes in biomechanical between theexperimental group and the control group.Methods: We randomly selected18healthy New Zealand white rabbitsas experimental objects, draw the blood In each rabbit central ear artery. Thenhave blood centrifugation, remove the lower red cell and upper excess plasma, put in the refrigerator. With operation cause the cartilage of the knee jointinjury model of rabbit femur after anesthesia, the size of2mm by3mm, thethickness is about0.3mm, and the prepared0.5mlPRP was injected into theright knee with the addition of thrombin and calcium gluconate,then suturedthe knee. The left knee as control group, causing cartilage injury of knee jointand injection of saline. No braking measures when the rabbit awoke.6rabbitswere killed respectively. in1weeks,3weeks,5weeks after operation,observation of cartilage changes, amputation of frozen spare. Anotherrandomly selected6healthy New Zealand rabbits were used in the experiment,after knee operation, cause cartilage injury model6as cartilage injury group,the intact knee6as intact group, amputation of frozen spare. Thaw the48cases of knee joint of rabbit one day before the experiment at rommtemperature, removal the meniscus and excess soft tissue, cut off the anteriorand the posterior cruciate ligament, fixed on the biomechanical testingmachine, with the speed of5mm/min, the maximum50N stress, used thePrescale pressure sensitive paper test knee medial and lateral articular contactpressure and contact area, calculate the joint contact area by using Auto CADsoftware segment of irregular figure area measurement, joint contactpressure using the Fuji Corp pressure reader to read.Results: The general observation of the postoperative1,3weeks, thePRP team could visible cartilage tissue, slightly rough surface, the defect areaborder does not disappear;5weeks after injection of PRP damaged cartilagecartilage tissue repair, cartilage surface was smooth and shiny, defect areaboundary disappear. The control group after1weeks, no significant cartilagerepair, after3,5weeks is still visible cartilage defect, defect edge hyperplasia,mild osteophyte formation, cartilage degeneration.Biomechanical testing showed that cartilage defect group and intactgroup compared with medial tibiofemoral joint contact area increases, thelateral is reduced, there is significant difference (P<0.05); and the contactpressure was not statistically difference with medial(P>0.05), there weresignificant differences in the lateral (P<0.05). Injection of PRP group compared with the complete knee joint in the tibiofemoral joint, medial andlateral contact area after5weeks, no significant difference (P>0.05); thecontact pressure in the tibiofemoral joint, after3and5weeks, no significantdifference (P>0.05). Injection of NS group compared with intact group in thetibiofemoral joint, medial and lateral contact area after1,3,5weeks werestatistically significant differences (P<0.05), and5weeks after operation themedial and lateral contact area were significant differences (P<0.05); the NSgroup and intact group compared statistically significant differences in themedial and lateral tibiofemoral joint contact pressure after5weeks(P<0.05),and medial contact pressure is larger than the lateral contact pressure(P<0.05).Conclusion: First, the tibiofemoral joint medial cartilage injury increasesthe contact area, the biomechanical characteristics of knee joint will changeunder high pressure, activities such as long time after failing to take effectivemeasures to repair, the formation of irreversible injury of knee jointbiomechanics will come true after5weeks, the original balance will be broken,degeneration aggravating; Second, the knee articular cartilage injury usingPRP can repair damaged cartilage, new cartilage tissue close to the normalcartilage tissue in biomechanical properties in5weeks.