Search

Magnesium (Mg) is a promising biodegradable metal for orthopedic applications, and plasma electrolytic oxidation (PEO) has been widely studied as a corrosion protection coating on Mg-based implants. However, the porous structures and easily formed cracks in fluid are disadvantageous for long-term corrosion protection. In this study, a SiO

Background Traditional tension band wiring and plate fixation represent the commonest methods for treating olecranon fractures. However, there is no agreement on which method provides the best outcome. The aim of this retrospective study is to compare the outcomes of tension band wiring (TBW) and plate fixation (PF) for treating displaced olecranon fractures. This is the first study to use propensity score matching analysis to compare treatment methods for olecranon fracture. Method A total of 107 patients aged between 18 and 85 had acute isolated and displaced olecranon fractures. The patients were divided into either TBW (n = 49) or PF (n = 58) groups. To conduct propensity score matching for the treatment method (TBW versus PF), 58 patients were analyzed by logistic regression (29 patients in each group). Various demographic and treatment-related variables were examined and analyzed to determine their correlation. Results Functional effects between two groups are similar (in terms of Mayo Elbow Performance Score (MEPS), the patients’ range of elbow motion (ROM) and forearm rotation (RFR), the time return to work (RTW)). The total adverse events rate and metalwork removal events rate are higher in TBW than that in PF. After propensity score matching analysis, similar primary treatment efficacy (indicated by MEPS> 90) in 2 groups and more primary adverse events (indicated by metalwork removal) were perceived in TBW than that in PF. Logistic regression analysis revealed that fracture type was an independent factor that affected the efficacy of a treatment (regression coefficient = − 1.24 , indicating that fracture severity was inversely proportional to the efficacy of a treatment for olecranon fracture. Furthermore, logistic regression analysis demonstrated that the treatment method was an independent factor that affected metalwork removal of olecranon fracture (regression coefficient 2.38 > 0, OR = 10.77, P , indicating that the risk of metalwork removal in the TBW Group was 10.77 times that in the PF Group. Conclusion When initially discussing the surgical approach with patients, physicians should fully weigh the possibility that TBW may lead to a second surgery due to the higher risk of internal fixation removal and that TBW won’t yield better functional outcomes than PF .

Aseptic loosening is the main factor that leads to the failure of orthopedic implants. Enhancing the early osteointegration of a bone implant can lower the risk of aseptic loosening. Here, a Li-doped surface was constructed on a Ti surface via plasma electrolytic oxidation (PEO) to improve osteointegration. The prepared Li-doped PEO coating showed a porous morphology and the sustained release of Li ions.

The response of immune systems is crucial to the success of biomedical implants in vivo and in particular, orthopedic implants must possess appropriate immunomodulatory functions to allow sufficient osteointegration. In this work, lithium (Li) is incorporated into titanium (Ti) implants by plasma electrolytic oxidation to realize slow and sustained release of Li ions. In vitro cellular behaviors of mice bone marrow derived macrophages (BMDMs), including gene expression, cytokine secretion, and surface marker analysis suggest that a low dose of Li incorporation could enhance the recruitment of BMDMs, restrict pro-inflammatory polarization (M1 phenotype), and promote anti-inflammatory polarization (M2 phenotype). The in vivo air pouch implantation model is constructed to simulate the microenvironment associated with aseptic loosening and the histology results confirm that a small dose of Li could relieve inflammatory reactions surrounding the implants. Moreover, compared to the Li-free group, the macrophage-conditioned culture medium (MCM) from Li-doped samples is more beneficial for the osteogenic differentiation of the mouse embryo cell line (C3H10T1/2) and angiogenesis of human umbilical vein endothelial cells (HUVECs), which is further confirmed by better osteointegration ability in the bone implantation model of Li-incorporating Ti implants. Furthermore, the molecular mechanism study discloses that osteoimmunomodulatory activity of Li-incorporating Ti implants is achieved by regulating the cascade molecules in the PI3K/AKT signalling pathway. This work reveals that favorable immune-modulated osteogenesis and osseointegration of bone implants can be realized by the incorporation of Li which broadens the strategy to develop the next generation of immunomodulatory biomaterials.

Background: Traditional tension band wiring and plate fixation represent the most common methods for treating olecranon fractures. However, there is no agreement as to which method provides the best outcome. The aim of this retrospective study was to compare the outcomes of tension band wiring (TBW) and plate fixation (PF) for treating displaced olecranon fractures. This is the first study to use propensity score matching analysis to compare treatment methods for olecranon fracture.Method: A total of 107 patients aged between 18 and 85 years old had acute isolated and displaced olecranon fractures. The patients were divided into either TBW (n=49) or PF (n=58) groups. To conduct propensity score matching for the treatment method (TBW versus PF), 58 patients were analyzed by logistic regression (29 patients in each group). Various demographic and treatment-related variables were examined and analyzed to determine their correlation. Results: Functional effects between two groups are similar( in terms of Mayo Elbow Performance Score (MEPS), the patients’ range of elbow motion (ROM) and forearm rotation (RFR), the time return to work (RTW)). The total adverse events rate and metalwork removal events rate are higher in TBW than that in PF. After propensity score matching analysis, the similar primary treatment efficacy (indicated by excellent MEPS) and higher primary adverse events rate ( indicated by metalwork removal) were perceived in TBW than that in PF. Logistic regression analysis revealed that fracture type was an independent factor that affected the efficacy of a treatment (regression coefficient=-1.24 0, OR = 10.77, P < 0.01), indicating that the risk of metalwork removal in the TBW Group was 10.77 times that in the PF Group.Conclusion: The results indicated that plate fixation should be the first choice of treatment method for olecranon fractures, especially in younger patients with higher quality of life requirements.Trial regislation: The study was not registered in the clinical trial registration center, because it was a retrospective case-control study, which was an observational study with no intervention measures.Level of evidence: Level III; Retrospective Cohort Comparison; Treatment Study

We have demonstrated that angiogenesis in acellular nerve allografts (ANAs) can promote neuroregeneration. The present study aimed to investigate the microvascular regeneration pattern of ANAs in Sprague-Dawley (SD) rats.Sixty male SD rats were randomly divided into an autologous group and a rat acellular nerve allograft group (rANA), and 10-mm sciatic nerve defects were induced in these rats. On the 7th, 14th and 21st days after surgery, systemic perfusion with Evans Blue (EB) or lead oxide was performed on the rats through carotid intubation. Samples were then collected for gross observation, and the microvessels in the nerves were reconstructed through microscopic CT scans using MIMICS software. The vascular volume fraction (VF, %) and microvessel growth rate (V, mm/d) in both groups were then measured, and 1 month after surgery, NF-200 staining was performed to observe and compare the growth condition of the axons.Early post-operative perfusion with gelatin/EB showed EB permeation around the acellular nerve. Perfusion with gelatin/lead oxide showed that the blood vessels had grown into the allograft from both ends 7 days after the operation. Fourteen days after the operation, the microvessel growth rate of the autologous group was faster than that of the rANA group (0.39 ± 0.17 mm/d vs. 0.26 ± 0.14 mm/d, p 0.05), and the vascular VF was also higher than that of the rANA group (8.92% ± 1.54% vs. 6.31% ± 1.21%, p 0.05). Twenty-one days after the operation, the blood vessels at both ends of the allograft had connected to form a microvessel network. The growth rate was not significantly different between the two groups; however, the vascular VF of the autologous group was higher than that of the rANA group (12.18% ± 2.27% vs. 9.92% ± 0.84%, p 0.05). One month after the operation, the NF-200 fluorescence (IOD) in the autologous group significantly increased compared with that of the rANA group (540,278 ± 17,424 vs. 473,310 ± 14,636, respectively, p 0.05), suggesting that the results of the repair after nerve injury were significantly better in the autologous group than in the rANA group.Both the autologous nerve and ANAs rely on the permeation of tissue fluids to supply nutrients during the early stage, and microvessel growth mainly starts at both ends of the graft and enters the graft along the long axis. Compared to ANAs, the growth speed of revascularization in autologous nerve grafts was faster, leading to a better outcome in the autologous nerve group.

Vascularization of acellular nerves has been shown to contribute to nerve bridging. In this study, we used a 10-mm sciatic nerve defect model in rats to determine whether cartilage oligomeric matrix protein enhances the vascularization of injured acellular nerves. The rat nerve defects were treated with acellular nerve grafting (control group) alone or acellular nerve grafting combined with intraperitoneal injection of cartilage oligomeric matrix protein (experimental group). As shown through two-dimensional imaging, the vessels began to invade into the acellular nerve graft from both anastomotic ends at day 7 post-operation, and gradually covered the entire graft at day 21. The vascular density, vascular area, and the velocity of revascularization in the experimental group were all higher than those in the control group. These results indicate that cartilage oligomeric matrix protein enhances the vascularization of acellular nerves.

Our group pioneered the study of nerve regeneration in China and has successfully developed human “acellular nerve grafts (ACNGs)”. However, our clinical studies revealed that the effects of ACNGs for long and large nerve defects are far from satisfactory. To improve the efficacy of ACNGs, we combined Cartilage oligomeric matrix protein angiopoietin-1 (COMP-Ang1) with ACNGs in rat sciatic nerve injury models and observed the outcomes via angiographic, morphological, and functional analyses. Co-cultures of endothelial cells (ECs) and dorsal root ganglion neurons (DRGs) were also used to characterize the relationship between neovascularization and nerve regeneration. The results showed significant improvements in early neovascularization, nerve regeneration, and functional outcomes in vivo in the ACNG + COMP-Ang1 group. In vitro, neurite length, and density as well as the expression levels of neurofilament 68 (NF68) and phosphorylated-Tie-2 (p-Tie-2) significantly increased when ECs were co-cultured with DRGs using COMP-Ang1. p-Tie-2 expression dramatically decreased after treatment with a Tie-2 kinase inhibitor (S157701), which consequently decreased the level of NF68. COMP-Ang1 can be concluded to promote early neovascularization followed by brisk nerve regeneration, and the mechanism of this regeneration may involve the modulation of the p-Tie-2 and Tie-2 receptors on ECs. These findings demonstrate that ACNGs can be modified using COMP-Ang1 to improve their efficacy in repairing peripheral nerve defects in clinical trials.