Finite element analysis of the stability of Mason type Ⅲ radial head fracture fixed with three cross-bridge headless compression screw and locking plate / 中国骨伤

OBJECTIVE@#To compare the biomechanical stability of three cross-bridge headless compression screws and locking plates in the fixation of Mason type Ⅲ radial head fractures by finite element method.@*METHODS@#Using reverse modeling technology, the radial CT data and internal fixation data of a healthy 25-year-old male were imported into the relevant software. Three-dimensional finite element model of 3 cross-bridge headless compression screws and locking plates for MasonⅢ radial head fractures were established, and the radial head was loaded with 100 N axial loading. The maximum displacement, maximum Von Mises stress and stress distribution of the two groups were compared.@*RESULTS@#The maximum displacements of the three cross-bridge screws group and locking plate group were 0.069 mm and 0.087 mm respectively, and the Von Mises stress peaks were 18.59 MPa and 31.85 MPa respectively. The stress distribution of the three screws group was more uniform.@*CONCLUSION@#Both internal fixation methods can provide good fixation effect. CoMPared with the locking plate fixation method, the 3 cross-bridge headless compression screws fixation is more stable and the stress distribution is more uniform.

Activation of nuclear factor kappaB signaling pathway in human osteoblasts responses to Staphylococcus aureus in vitro / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate whether S. aureus could activate NF-κB signaling pathway in human osteoblasts.</p><p><b>METHODS</b>Immunoblot and electrophoretic mobility shift assay were used to detect the degradation of I-κBα and activation of NF-κB in human osteoblasts following infection with S.aureus, respectively, and there were investigated the activated state of NF-κB signaling pathway in human osteoblasts. In addition, enzyme-linked immunosorbent assay was used to measure the secretion of IL-6 in culture supernatants, which was represented as one of important cytokines in osteomyelitis, and an inhibitor of NF-κB, SN50, which was added to human osteoblasts culture prior to 1 hour at 50 µmol/L before the infection of S.aureus, was used to determine whether S.aureus-activated NF-κB signaling pathway regulates IL-6 secretion of human osteoblasts.</p><p><b>RESULTS</b>S.aureus could induce the degradation of I-κBα (I-κBα(15 min)/I-κBα(0 min) = 0.409 ± 0.245 and I-κBα(30 min)/I-κBα(0 min) = 0.061 ± 0.010) and activation of NF-κB in human osteoblasts in a time and dose-dependent manner following infection. In addition, the secretion of IL-6 in the supernatants of human osteoblasts ((2.17 ± 0.11) µg/L) was suppressed by 50 µmol/L SN50 compared to without the addition of SN50 ((3.58 ± 0.31) µg/L) (F = 174.25, P < 0.05).</p><p><b>CONCLUSIONS</b>S.aureus could activate NF-κB signaling pathway in human osteoblasts, which could regulate cytokines secretions of human osteoblasts.</p>