Experimental Study On A Novel PU/N-HA+PA66 Composite Material For Repair Articular Cartilage Defects

Objective : To evaluate the effect of repair with PU/n-HA+PA66 biological composite material on articular cartilage and subchondral bone.Methods :Twenty healthy adult dogs were used for the models of articular cartilage defects by perforating on the knee joint,with 6mm diameter and 12mm depth.Three materials were offered by the Analytical and Testing Center of Sichuan University,its specification was wafer,diameter 6 mm,height 12 mm.Twenty dog models were at random divided into 4 groups:porous PU/n-HA+PA66 implant group, compact PU/n-HA+PA66 implant group, n-HA+PA66 implant group and blank control group. The macroscopic, histological evaluation were performed at 4,12,24 weeks postoperatively. The interfaces of biomaterial implants with articular cartilage were observed by scanning electron microscope.Results:1. At 12 weeks after weeks after implantation, the bone tissue were found growing into lower layer materials; at 24 weeks after weeks after implantation, the bone tissue which were obviously more than at 12 weeks after weeks after implantation were found in the mesh of the lower layer materials n-HA+PA66, and the n-HA+PA66 scaffold were combined closely with the bone tissue surrounding the n-HA+PA66 scaffold, the n-HA+PA66 scaffold and the bone were fused absolutely.2. At 12 weeks after the implantation of the porous PU/n-HA+PA66, the upper layer of the scaffold porous PU were combined closely with the articular cartilage surrounding it, and the surface of the articular was smooth, and the articular cartilage surrounding the porous PU were not degeneration obviously; there is a gap between the compact PU and the cartilage surrounding it, the articular cartilage surrounding the compact PU were degeneration. At 24 weeks after implantation of the porous PU/n-HA+PA66, the upper layer of the scaffold porous PU were combined more closely with the articular cartilage surrounding it than at 12 weeks after implantation, and some cartilage grown from the articular cartilage surrounding the scaffold porous PU to the surface of the the scaffold porous PU; there is still a gap between the compact PU and the cartilage surrounding it, and the articular cartilage surrounding the compact PU were degeneration(the cartilage became thinner and the color of it turned white).3. The histological score of the in the group implanted by the porous PU/n-HA+PA66 were higher than that in the compact PU/n-HA+PA66,the n-HA+PA66 groups and the control groups (10.71±1.13 vs.5.41±0.67,3.69±0.48,4.01±0.39,P < 0.05)。4. At 24 weeks after the implantation of the porous PU/n-HA+PA66 and the compact PU/n-HA+PA66, the porous PU were more closelier connected with surrounding articular cartilage than the compact PU, and the articular cartilage surrounding the compact PU degenerated obviously under scanning electron microscope.Conclusion : The new type biological composite materials PU/n-HA+PA66 have good function for replacing articular cartilage and subchondral bone and have good biocompatibility and biological mechanical properties. So it has potential application value in clinical works.