Study on the effect of self-made fracture positioning compression guide device for posterior malleolus fracture surgery: Medical prevention.

To evaluate the effectiveness of a self-designed pressure-guided fracture positioning device, a prospective study was conducted in patients with posterior ankle fractures undergoing surgery using the device. Twenty-seven cases of ankle joint fracture with posterior malleolus fracture were treated by surgery. In the process of fixing posterior malleolus fracture, a self-designed fracture positioning compression guide device was used to fix posterior malleolus bone by anterior and posterior approaches. Postoperative CT images were used to assess the fixation position as well as length of the screw and the compression of the fracture. All patients had healed ankle fractures, and the anterior-posterior screws were fixed in the central area of the posterior malleolus. Posterior malleolus fragment displacement was <2 mm. The screw effectively secured the cortex beyond the length of the posterior malleolus cortex by no more than two threads. The good rate of ankle joint function was 85.16%. Compared to traditional surgical techniques, minimally invasive fixation using the self-designed positioning compression guide device has several advantages, including smaller trauma, faster postoperative recovery, and improved patient satisfaction. The device also provides the surgeon with greater control and precision during the surgical procedure, which can contribute to better surgical outcomes.

Strontium-doped gelatin scaffolds promote M2 macrophage switch and angiogenesis through modulating the polarization of neutrophils.

The immune system mediates inflammation, vascularization and the first response to injuries or implanted biomaterials. Although the function of neutrophils in tissue repair has been extensively studied, its complete role in the tissue regeneration of biomaterials, specifically the resolution of inflammation and promotion of angiogenesis, is unclear. Here, we fabricate nanofibrous gelatin scaffolds containing 10% (w/w) strontium-hydroxyapatite (SrHA) via phase-separation methods to investigate Sr-mediated regulation of neutrophil polarization and, subsequently, the effects on angiogenesis and macrophage polarization. Compared with neutrophils cultured on pure gelatin or HA-incorporated gelatin scaffolds, neutrophils on SrHA-incorporated gelatin scaffolds show more N2 polarization in vitro and in vivo and significantly greater production of immunomodulatory and angiogenic factors. The Sr-induced immunomodulatory and proangiogenic functions of neutrophils are mediated through NF-κB pathway downregulation and increased STAT3 phosphorylation. Thus, neutrophils play a vital role in tissue engineering, and Sr-incorporated scaffolds efficiently promote neutrophil polarization to the N2 phenotype, enhancing resolution of inflammation and ultimately promoting angiogenesis and tissue regeneration. Thus, incorporation of neutrophils in analyses of the immune characteristics of scaffolds and the development of immunomodulatory biomaterials that can regulate neutrophils are novel and promising strategies in tissue engineering.

Varisized 3D-Printed Lunate for Kienböck's Disease in Different Stages: Preliminary Results.

OBJECTIVE: To evaluate the feasibility of arthroplasty with varisized three-dimensional(3D) printing lunate prosthesis for the treatment of advanced Kienböck's disease (KD). METHODS: From 2016 November to 2018 September, a retrospective study was performed for the patients of KD in our hospital. Five patients (two males, three females) were included in this study. The mean age of the patients at the time of surgery was 51.6 years (range, 37-64 years). Varisized prosthesis identical to the live model in a ratio of 1:0.85, 1:1, and 1:1.1 were fabricated by 3D printing. All patients (one in Lichtman IIIA stage, two in Lichtman IIIB stage, one in Lichtman IIIC stage, and one in Lichtman IV stage) were treated with lunate excision and 3D printing prosthetic arthroplasty. Visual analog scale score (VAS), the active movement of wrist (extension, flexion) and strength were assessed preoperatively and postoperatively. The Mayo Modified Wrist Score (MMWS), Disabilities of the Arm, Shoulder and Hand (DASH) Score, and patient's satisfaction were evaluated during the follow-up. RESULTS: Prosthesis identical to the live model in a ratio of 1:0.85 or 1:1 were chosen for arthroplasty. The mean operation time (range, 45 to 56 min) was 51.8 ± 4.44 min. Follow-up time ranged from 11 months to 33 months with the mean value of 19.4 months. The mean extension range of the wrist significantly increased from preoperative 44° ± 9.6° to postoperative 60° ± 3.5° (P < 0.05). The mean flexion range of the wrist significantly increased from preoperative 40° ± 10.6° to postoperative 51° ± 6.5° (P < 0.05). The active movement of wrist and strength were improved significantly in all patients. VAS was significantly reduced from 7.3 preoperatively to 0.2 at the follow-up visit (P < 0.05). The mean DASH score was 10 (range, 7.2-14.2), and the mean MMWS was 79 (range, 70-90). There were no incision infection. All patients were satisfied with the treatment. CONCLUSIONS: For patients suffering advanced Kienböck's disease, lunate excision followed by 3D printing prosthetic arthroplasty can reconstruct the anatomical structure of the carpal tunnel, alleviate pain, and improve wrist movement.

Mussel-Inspired Nanostructures Potentiate the Immunomodulatory Properties and Angiogenesis of Mesenchymal Stem Cells.

The therapeutic effects of mesenchymal stem cells (MSCs)-material constructs mainly come from the secretion of trophic factors from MSCs, especially the immunomodulatory and angiogenic cytokines. Recent findings indicate the significance of topographical cues from these materials in modulating paracrine functions of MSCs. Here, we developed functionalized three-dimensional-printed bioceramic (BC) scaffolds with a mussel-inspired surface coating in order to regulate the paracrine function of adipose-derived MSCs (Ad-MSCs). We found that Ad-MSCs cultured on polydopamine-modified BC scaffolds (DOPA-BC) significantly produced more immunomodulatory and pro-angiogenic factors when compared with those cultured on BC scaffolds or microplates. Functional assays, such as endothelial progenitor cells migration, tube formation, and macrophage polarization, were performed to confirm the enhanced paracrine functions of the secreted trophic factors from Ad-MSCs cultured on DOPA-BC scaffolds. Further investigation identified that both focal adhesion kinase- and extracellular signal-related kinase signaling were the required mechano-transduction pathways through which the mussel-inspired surface stimulated the paracrine effect of Ad-MSCs. In a diabetic skin-defect-healing model in rats, conditioned medium received from the Ad-MSCs cultured on DOPA-BC sped wound closure, enhanced vascularization, and promoted macrophage switching from a proinflammatory M1 to a pro-healing and anti-inflammatory M2 phenotype in the wound bed. These results demonstrate that a bio-inspired coating with polydopamine represents an effective method to enhance the paracrine function of MSCs. Our findings illustrate a novel strategy to accelerate tissue regeneration by guiding the paracrine-signaling network.

3D-printed IFN-γ-loading calcium silicate-ß-tricalcium phosphate scaffold sequentially activates M1 and M2 polarization of macrophages to promote vascularization of tissue engineering bone.

To promote vascularization of tissue-engineered bone, IFN-γ polarizing macrophages to M1 was loaded on 5% calcium silicate/ß-tricalcium phosphate (CaSiO3-ß-TCP) scaffolds. IFN-γ and Si released from the scaffold were designed to polarize M1 and M2 macrophages, respectively. ß-TCP, CaSiO3-ß-TCP, and IFN-γ@CaSiO3-ß-TCP were fabricated and biocompatibilities were evaluated. Polarizations of macrophages were detected by flow cytometry. Human umbilical vein endothelial cells with GFP were cultured and induced on Matrigel with conditioned culture medium extracted from culture of macrophages loaded on scaffolds for evaluating angiogenesis. Four weeks after the scaffolds were subcutaneously implanted into C57B1/6, vascularization was evaluated by visual observation, hematoxylin and eosin staining, as well as immunohistochemistry of CD31. The results showed that IFN-γ@CaSiO3-ß-TCP scaffolds released IFN-γ in the early stage (1-3 days) to stimulate macrophages to M1 polarization, followed by release of Si inducing macrophages to M2 polarization while scaffolds degraded. The activation of M1/M2 allows macrophages to secrete more cytokines, including VEGF, CXCL12 and PDGF-BB. The IFN-γ@CaSiO3-ß-TCP scaffolds formed more blood vessels in vitro and in vivo compared to the control groups. The study indicated that the design of tissue-engineered scaffolds with immunomodulatory function utilized host macrophages to increase vascularization of tissue-engineered bone, providing a new strategy for accelerating vascularization and osteogenesis of tissue-engineered scaffolds and showing the potential for treatment of major bone defects. STATEMENT OF SIGNIFICANCE: A 3-D printed immunomodulatory scaffold was designed for repair of massive bone defects. Through the release of interferon γ and silicon ions, the new immunomodulatory scaffold promoted the M1 and M2 polarization of macrophages, boosting angiogenesis. This scaffold provided a new strategy for accelerating vascularization and osteogenesis of tissue-engineered scaffolds and showing the potential for treatment of major bone defects.