Kun Zhang

Analysis of the Stress and Displacement Distribution of Inferior Tibiofibular Syndesmosis Injuries Repaired with Screw Fixation: A Finite Element Study

Background Studies of syndesmosis injuries have concentrated on cadaver models. However, they are unable to obtain exact data regarding the stress and displacement distribution of various tissues, and it is difficult to compare models. We investigated the biomechanical effects of inferior tibiofibular syndesmosis injuries (ITSIs) and screw fixation on the ankle using the finite element (FE) method. Methodology/Principal Findings A three-dimensional model of a healthy ankle complex was developed using computed tomography (CT) images. We established models of an ITSI and of screw fixation at the plane 2.5 cm above and parallel to the tibiotalar joint surface of the injured syndesmosis. Simulated loads were applied under three conditions: neutral position with single-foot standing and internal and external rotation of the ankle. ITSI reduced contact forces between the talus and fibula, helped periarticular ankle ligaments withstand more load-resisting movement, and increased the magnitude of displacement at the lower extreme of the tibia and fibula. ITSI fixation with a syndesmotic screw reduced contact forces in all joints, decreased the magnitude of displacement at the lower extreme of the tibia and fibula, and increased crural interosseous membrane stress. Conclusions/significance Severe syndesmosis injuries cause stress and displacement distribution of the ankle to change multidirectional ankle instability and should be treated by internal fixation. Though the transverse syndesmotic screw effectively stabilizes syndesmotic diastasis, it also changes stress distribution around the ankle and decreases the joints range of motion (ROM). Therefore, fixation should not be performed for a long period of time because it is not physiologically suitable for the ankle joint.

Overexpression of HMGB1 A-box reduced IL-1β-induced MMP expression and the production of inflammatory mediators in human chondrocytes

The pro-inflammatory cytokine interleukin-1 beta (IL-1β) plays a crucial role in the pathogenesis of osteoarthritis (OA) by stimulating several mediators that contribute to cartilage degradation. The aim of this study was to investigate the effects and mechanism of high mobility group box 1 (HMGB1) inhibitors HMGB1 A-box on the expression of matrix metalloproteinase (MMP) and the production of inflammatory mediators in human osteoarthritis chondrocytes after activation by IL-1β. We found that the overexpression of HMGB1 A-box significantly decreased the IL-1β-stimulated the production of MMP-1, MMP-3 and MMP-9, and also reduced the elevated levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) associated with the inhibition of prostaglandin E2 (PGE2) and nitric oxide (NO) production in IL-1β-stimulated chondrocytes. In addition, overexpression of the HMGB1 A-box significantly inhibited the up-regulation of ADAMTS-4, ADAMTS-5 and HMGB1 caused by IL-1β in chondrocytes. Moreover, the overexpression of HMGB1 A-box markedly suppressed the IL-1β-mediated activation of the Toll-like receptor 4 (TRL4)/NF-κB pathway. Our observations indicated that the HMGB1 A-box can play a protective role by suppressing the IL-1β-induced expression of MMPs and that the production of inflammatory mediators in chondrocytes was associated with suppression of the HMGB1/TLR4/NF-κB pathway. In conclusion, HMGB1 A-box relieves the development of OA that may be associated with regulating the HMGB1/TLR4/NF-κB pathway.

Surgical treatment of acetabulum top compression fracture with sea gull sign.

To investigate surgical procedures and their efficacy for acetabulum top compression fractures with sea gull sign.

Effects of inferior tibiofibular syndesmosis injury and screw stabilization on motion of the ankle: a finite element study

AbstractPurposenTraditional studies of syndesmosis injury and screw stabilization have been conducted in cadaveric models, which cannot yield sufficient and exact biomechanical data about the interior of the ankle. The purpose of this study was to evaluate the effects of inferior tibiofibular syndesmosis injury (ITSI) and screw stabilization on the motion of the ankle with finite element analysis.MethodsnThree-dimensional models of the ankle complex were created with CT images of a volunteer’s right ankle in three states: normal, post-ITSI, and stabilization with a screw 2.5xa0cm above (parallel to) the ankle. Simulated loads were applied under three conditions: neutral position with single foot standing, internal rotation, and external rotation of the ankle.ResultsCompared with the normal state, ITSI increased the relative displacement between the lower extremes of the tibia and fibula in the anteroposterior and mediolateral directions and the angular motion of the tibia, fibula, and talus at internal and external rotations (ERs). However, when stabilized with syndesmotic screws, the range of motion (ROM) and all these parameters significantly decreased.ConclusionITSI can lead to internal and ER instability of the ankle joint. Screw stabilization is effective in controlling the instability, but may reduce markedly the ROM of the ankle joint. Through this study, it can be proposed that the screws should be removed once the healing is gained in order to restore normal function of the ankle joint as soon as possible.

Minimally invasive stabilisation of posterior pelvic ring instabilities with pedicle screws connected to a transverse rod

PurposeThe goal was to evaluate the clinical outcomes, quality of reduction and complications of pelvic fractures treated by minimally invasive stabilisation of posterior pelvic ring instabilities with pedicle screws connected to a transverse rod.MethodsRetrospective analysis of prospectively collected data in a consecutive patient series with pelvic fractures treated by minimally invasive stabilisation of posterior pelvic ring instabilities with pedicle screws between January 2010 and January 2016. The functional outcomes evaluated by Majeed scores, and fracture reduction results were evaluated using the Tornetta and Matta standard. As well as recording the duration of the surgical procedure, intraoperative blood loss, the times of intra-operative fluoroscopy and complications.ResultsA total of 29 patients (15 men and 14 women; age range, 21–72xa0years; mean, 40.8xa0years) could be followed-up after an average of 38.2u2009±u200921.3xa0months (range, 12-84xa0months). According to the AO/OTA classification, there were 24 patients with B2 injury and five patients with C1 injury of the pelvic ring. For the sacral fractures, according to Denis classification, four cases were zone I fractures and 25 cases were zone II fractures. The duration of the surgical procedure, intra-operative blood loss and the times of intra-operative fluoroscopic of the posterior-ring surgical procedure was 28.2u2009±u20094.6xa0minutes (range, 20–38xa0minutes), 46.7u2009±u20094.9xa0ml (range, 39–56xa0ml), and 13.1u2009±u20091.6xa0seconds (range, 10–17xa0seconds) respectively. Posterior-ring fracture reduction was excellent in 11 patients and 15 were good, three cases were fair; the excellent and good rate was 89.7% (26/29). At the final follow-up, the function result was rated as excellent in ten cases, good in 16, fair in three, and poor in zero cases; the excellent and good rate was 89.7% (26/29). There was no incision infection, intra-operative neurovascular injury, pedicle screw loose or breakage, and non-union of the posterior arch did not occur. Two patients requested removal of the fixator: one patient with breakage of the anterior pelvic ring internal fixator, and the pedicle screw was also taken out in the same operative session; another one with moderate pain on the posterior pelvic ring.ConclusionsMinimally invasive stabilisation of posterior-pelvic-ring instabilities with pedicle screw connected to a transverse rod may be a good alternative to sacroiliac screw fixation because it is quick, safe and associated with a good functional outcome; thus being a useful option in patients who do not qualify for sacroiliac screw fixation.

Molecular characterization of metastatic osteosarcoma: Differentially expressed genes, transcription factors and microRNAs

The present study aimed to understand the molecular mechanisms underlying osteosarcoma metastasis. Microarray dataset GSE49003 was downloaded from the Gene Expression Omnibus database and used for analysis. Raw expression data were preprocessed using the preprocessCore, impute and aggregate packages in R. Differentially expressed genes (DEGs) between metastatic and non‑metastatic osteosarcoma cell lines were screened using the limma package following exclusion of DEGs with a higher significance in intra‑groups compared with inter‑groups using the genefilter package. Enrichment analysis was performed on DEGs using TargetMine, followed by identification of transcription factors (TFs) and microRNAs (miRNAs). Regulatory networks were constructed using Cytoscape software. A total of 248 upregulated and 208 downregulated genes were obtained. The upregulated genes were significantly enriched in the following pathways: Downregulation of transforming growth factor β (TGF‑β) receptor signaling and TGF‑β receptor signaling activates SMADs; these upregulated genes included protein phosphatase 1, regulatory subunit 15A, transforming growth factor, β receptor II and ubiquitin carboxyl‑terminal hydrolase L5. In addition, some upregulated genes were enriched in lung cancer disease ontology, including epidermal growth factor receptor (EGFR), insulin‑like growth factor 2 mRNA binding protein 3 (IGF2BP3), runt‑related transcription factor 3 (RUNX3) and secreted frizzled‑related protein 1 (SFRP1). Conversely, the downregulated genes were significantly enriched in extracellular matrix‑associated pathways or functions, such as collagen, type XII, α 1; collagen, type I, α 1; collagen, type IV, α 1; and collagen, type V, α 1. In addition, some downregulated genes were significantly enriched in the TGF‑β signaling pathway, including bone morphogenetic protein 4, inhibitor of DNA binding 3 and SMAD family member 6. A total of 10 TFs and 84 miRNAs (e.g. miR-21-5p) were deemed to be associated with DEGs. In conclusion, DEGs enriched in the downregulation of TGF‑β receptor signaling, TGF‑β receptor signaling activates SMADs and TGF‑β signaling pathways, as well as the extracellular matrix may be implicated in the progression of osteosarcoma metastasis. Dysregulated EGFR, IGF2BP3, RUNX3 and SFRP1 may contribute to the metastasis of osteosarcoma to the lungs. In addition, screened TFs and miR-21-5p may be associated with metastasis via target genes.

Tranexamic acid reduces hidden blood loss in the treatment of intertrochanteric fractures with PFNA: a single-center randomized controlled trial

BackgroundHidden blood loss is a major concern for patients undergoing hip surgery for intertrochanteric fracture. The objective of this study was to investigate whether tranexamic acid (TXA) could reduce postoperative hidden blood loss in patients undergoing hip surgery for intertrochanteric fracture.MethodsA total of 77 patients with intertrochanteric fracture were enrolled in this randomized controlled study. Patients received either 200xa0mL (1xa0g) of TXA (nxa0=xa037) or normal-saline (NS) (nxa0=xa040) i.v. before hip surgery using proximal femoral nail anti-rotation (PFNA). Hemoglobin and hematocrit levels were measured preoperatively and postoperatively at day 1 and 3. Visible and hidden blood loss volumes were calculated at postoperative day 3.ResultsOn postoperative day 3, the transfusion rate was significantly lower in the TXA group compared to the NS group, although mean hemoglobin and hematocrit levels were not significantly different between the two groups. However, the estimated hidden blood loss volume (210.09xa0±xa0202.14xa0mL vs. 359.35xa0±xa0290.12xa0mL; Pxa0<xa00.05) and total blood loss volume (279.35xa0±xa0209.11xa0mL vs. 417.89xa0±xa0289.56xa0mL; Pxa0<xa00.05) were significantly less in the TXA group compared to the NS group, respectively.ConclusionTXA significantly reduced postoperative hidden blood loss in patients with intertrochanteric fracture who underwent PFNA.(Registration number: ChiCTR-INR-16008134).

Bilaterally Primary Cementless Total Hip Arthroplasty for Severe Hip Ankylosis with Ankylosing Spondylitis: Cementless Total Hip Arthroplasty for as

Total hip arthroplasty is a reliable therapeutic intervention in patients with ankylosing spondylitis, in whom the aims of surgery are to reduce pain, restore hip function and improve quality of life. The current study is a retrospective analysis of the clinical and radiographic findings in a consecutive series of patients with hip ankylosis associated with severe ankylosing spondylitis who underwent bilateral primary total hip arthroplasty using non‐cemented components.

Curcumin inhibits hypoxia-induced proliferation and invasion of MG-63 osteosarcoma cells via downregulating Notch1

Curcumin is a biologically active ingredient abundantly present in the ground rhizomes of Curcumaxa0longa with a wide range of bioactive properties, including antitumor effects. Hypoxia is a common characteristic of solid tumors, including osteosarcoma. However, whether curcumin has antitumor effects on osteosarcoma under hypoxic conditions, and its underlying molecular mechanisms, remain unclear. The present study demonstrated that the MG‑63 osteosarcoma cell line exhibited increased proliferation and enhanced invasiveness upon exposure to hypoxic conditions. However, these effects were prevented by curcumin treatment. Further investigation revealed that curcumin may inhibit Notch1 upregulation induced by hypoxia. Overexpression of Notch1 via Notch1 cDNA transfection ameliorated curcumin‑inhibited MG‑63 cell growth under hypoxic conditions. Taken together, these data revealed that curcumin may suppress the growth of osteosarcoma cells in hypoxia via inhibiting Notch1 signaling.

A short buttress plate fixation of posterior column through single ilioinguinal approach for complex acetabular fractures

PurposeThe goal of this study was to evaluate the safety and efficacy of a new technique for posterior column fixation through the standard ilioinguinal approach.MethodsWe conducted a retrospective review involving 33 consecutive patients with complex acetabular fractures treated using a short buttress plate fixation of posterior column through single ilioinguinal approach. Radiographic evaluation was performed using criteria described by Matta. Functional outcome was assessed using modified Postel Merle D’Aubigné score.ResultsBetween 2008 and 2013, 33 adult patients with mean age of 46xa0years and mean follow up of 37.5xa0months were enrolled. Anatomic reduction was obtained in 61xa0% of cases, imperfect reduction in 24xa0% of cases and poor reduction in 15xa0% of cases. The average modified Merle d’Aubigné score was 15: categorized as excellent in seven, good in 18, fair in three, and poor in four. One patient died at 15xa0days because of pulmonary embolism. Four patients sustained temporary lateral femoral cutaneous palsy. At final follow up, two patients had severe post-traumatic arthritis; one of them underwent a total hip arthroplasty at 93xa0months. None of the patients had loss of reduction.ConclusionsA short buttress plate fixation of posterior column through single ilioinguinal approach for complex acetabular fractures is a safe and effective method.