BACKGROUND: Metal implants have been extensively applied in joint arthoplasty, but the stress shielding effect caused by its high elastic modulus results in a series of complications, such as bone resorption, bone atrophy and prosthesis loosening. Carbon fiber-reinforced polyetheretherketone (CF-PEEK) composites are anisotropic and exhibit more advantages used for prosthesis due to its low elastic modulus and high intensity.OBJECTIVE: To investigate the blood compatibility of CF-PEEK composites, and compare the biomechanical properties after arthroplasty between CF-PEEK composites and Co-Cr-Mo used for femoral head prosthesis. METHODS: (1) The blood compatibility of CF-PEEK composites was evaluated through hemolysis test. (2) Femoral samples from eight fresh cadavers were collected and randomly divided into two groups, followed by subjected to CF-PEEK and Co-Cr-Mo prosthesis replacement, respectively. The displacement between the prosthesis and bone was measured under loading 200, 400, 600, 800 and 1000 N, and the torsional strength after arthroplasty was detected.RESULTS AND CONCLUSION: (1) The hemolysis rate of the CF-PEEK composites was 3.23% < 5%, which was in line with the national standards for biological evaluation of medical devices. (2) The micromovement in distal prosthesis was significantly less than that of proximal prosthesis under different loads in both two groups (P < 0.05). (3) The torsion angle under different loads in the CF-PEEK group was significantly less than that in the Co-Cr-Mo group (P < 0.05), and the torsion stiffness in the CF-PEEK group was significantly higher than that in the Co-Cr-Mo group (P < 0.05). (4) To conclude,the CF-PEEK composites possess good blood compatibility and stability, which can be used as a prosthesis material.

Objective To observe the effect of platelet rich plasma(PRP)combined with core decompression on the steroid-induced avascular necrosis of the femoral head(SANFH)and on MMP/TIM in rabbits.Methods A total of 42 New Zealand white rabbits were used in this study,and were randomly divided into 3 groups(decompression,combination and control groups,each n=14). The rabbit model of SANFH was established by i.m. injecting prednisolone acetate in the decompression group and combination group. The improved Landesberg method was used to make the platelet rich plasma. The decompression group received core decompression treatment while the combination group received PRP combined with core decompression for bone repair. X-ray photography of the hip joint of the two groups were taken at 2,6 and 10 weeks after the surgery,and the Lane-Sandhu X-ray scores and new bone area ratio were compared. Venous blood samples of the 3 groups were collected and the bilateral femoral heads were taken for further examination. The left femoral heads were used for histopathological observation and the right ones were used to determine the expression of the mRNA of MMP-2,MMP-9, TIMP-1, and TIMP-2. Results The levels of MMP-2 and MMP-9 in the decompression group were higher than that in the combination group and control group after surgery. The levels of TIMP-1 and TIMP-2 in the decompression group were significantly lower than the combination group and control group(P < 0.05). The IL-6 level and the rate of empty bone lacunae in the decompression group were significantly higher than the combination group and control group(P < 0.05), and that of the combination group was higher than the control group(P < 0.05). The combination group had a better joint imaging and histopathological evaluation than the decompression group after surgery. Conclusions Our findings demonstrate that PRP combined with core decompression can exert a positive effect on the MMP/TIMP and bone tissue repair in the treatment of steroid-induced avascular necrosis of the femoral head in rabbits.

Objective To investigate the effect of tetrandrine(Tet)on injury of primary human articular chondro-cytes induced by interleukin-1β(IL-1β).Methods Human articular chondrocytes were divided into control group,IL-1β group,hypoxia inducible factor(HIF-1α)inhibitor group[2-methoxyestradiol(2-ME2)group],Tet groups containing low,medium and high concentrations.Each group has six replicated samples.MTT assay was used to de-tect the viability of cells;cell apoptosis was detected by flow cytometry;the level of inflammatory related factors like tumor necrosis factor-α(TNF-α),matrix metalloproteinase 3(MMP-3),inducible nitric oxide synthase(iNOS),cyclooxygenase-2(COX-2)and the activity of antioxidant factors like super oxide dismutase(SOD)and glutathione peroxides(GPx)in cells were detected by ELISA;Western blot was used to detect the expression of HIF-1α and VEGF in cells.Results Compared with the control group,the apoptosis rate,level of TNF-α,MMP-3,iNOS,COX-2 and the protein expression of HIF-1α and VEGF in IL-1β group all increased,the cell survival rate and the activity of SOD and GPx significantly decreased(P＜0.05);compared with IL-1β group,the apoptosis rate,the level of TNF-α,MMP-3,iNOS,COX-2 and the protein expression of HIF-1α and VEGF in 2-ME2 group and Tet groups with low,medium,and high concentration significanthy decreased(P＜0.05).The cell survival rate and the activity of SOD and GPx significantly increased(P＜0.05).Conclusions Tetrandrine attenuates IL-1β-in-duced injury of human articular chondrocytes.