Comparison of different internal fixation implants in the treatment of talar neck fractures: A finite element analysis.

OBJECTIVES: This study aimed to analyze the biomechanics of cannulated screws (CS) with or without a lateral locking plate (LLP) in talar neck fractures through a finite element analysis. PATIENTS AND METHODS: The computed tomography image of the talus from a healthy volunteer (adult male) was used to reconstruct a three-dimensional talar model. The method for fixing talar neck fractures with CS and an LLP was planned using computer-aided design software. Afterward, the three-dimensional models of comminuted talar neck fractures were used to simulate fixation with anteroposterior parallel dual CS, single CS+LLP, and dual CS+LLP. Finally, finite element analysis was carried out to compare the outcomes of dual CS+LLP to those of single CS+LLP and to those of using dual CS alone. The displacement and von Mises stress values of the three groups with different internal fixation were analyzed. RESULTS: For a simple talar neck fracture, the lowest amount of displacement was obtained with CS+LLP (0.407 mm), while dual CS (0.459 mm) showed the highest amount of total displacement; the lowest amount of peak stresses was obtained with CS+LLP (5.38 MPa), while dual CS (8.749 MPa) showed the highest amount of total peak stresses. For a comminuted talar neck fracture, the lowest amount of displacement was obtained with CS+LLP (0.398 mm), while dual CS (0.408 mm) showed the highest amount of total displacement; the lowest amount of peak stresses was obtained with CS+LLP (129.9 MPa), while dual CS (205.9 MPa) showed the highest amount of peak stresses. CONCLUSION: Compared to the other two groups, the dual CS+LLP group had better biomechanics properties in the displacement and stress peak of the talus and implant. Thus, the use of dual CS+LLP fixation is recommended for the surgical treatment of comminuted talar neck fractures.

Rare pattern of Maisonneuve fracture: A case report.

BACKGROUND: Maisonneuve fracture is a special type of ankle fracture that consists of proximal fibular fracture, a lesion of the inferior tibiofibular syndesmotic complex (interosseous ligament, anterior inferior tibiofibular ligament and posterior inferior tibiofibular ligament), and injury of the medial structure of the ankle (deltoid ligament tear or medial malleolar fracture). The accepted mechanism of Maisonneuve fracture is pronation external rotation according to the Lauge-Hansen classification. In this paper, we report a rare pattern of Maisonneuve fracture, which has the characteristics of both pronation external rotation ankle fracture and supination adduction ankle fracture. CASE SUMMARY: A 31-year-old female patient accidentally sprained her right ankle while walking 5 d before hospitalization in our hospital. The patient was initially missed in other hospitals and later rediagnosed in our outpatient department. Full-length radiographs of the lower leg revealed proximal fibula fracture, inferior tibiofibular joint separation, and medial malleolar fracture involving the posterior malleolus, which was also revealed on computed tomography scans. Magnetic resonance imaging revealed rupture of the anterior inferior tibiofibular ligament and anterior talofibular ligament. We diagnosed a rare pattern of Maisonneuve fracture with proximal fibular fracture, inferior tibiofibular joint separation, medial malleolar fracture and ruptures of the anterior inferior tibiofibular ligament and anterior talofibular ligament. The patient underwent open reduction and internal fixation in our hospital. A 6-mo postoperative follow-up confirmed a good clinical outcome. CONCLUSION: To our knowledge, this rare pattern of Maisonneuve fracture has not been previously described. The possible mechanism of injury is supination adduction combined with pronation external rotation. Careful analysis of the injury mechanism of Maisonneuve fracture is of great clinical significance and can better guide clinical treatment.

Correlation of CT Values and Bone Mineral Density in Elderly Chinese Patients with Proximal Humeral Fractures.

OBJECTIVE: To investigate the correlation between computed tomography (CT) values and bone mineral density (BMD) in elderly Chinese patients with proximal humeral fractures. METHODS: This was a single-center retrospective study involving 166 elderly patients with proximal humeral fractures between January and June 2015 in our hospital. Following the inclusion and exclusion criteria, 89 patients were finally enrolled in this study. The spiral CT scanning was performed on these patients, and the CT images were obtained by using MIMICS software. The CT values in axial, coronal, and sagittal images of healthy proximal humeri were measured using a circular region of interest (ROI) by Image J. The bone mineral density (BMD) of the lumbar spine and femoral neck was measured using dual-energy X-ray absorptiometry (DXA). Spearman rank correlation methods were used for analysis of the association between the proximal humerus average CT value (CTMean ) and the lumbar spine as well as femoral neck BMD in patients with proximal humeral fractures, or osteoporotic patients. RESULTS: Among the included 89 patients, there were 26 males and 63 females, 69% and 84% of whom were diagnosed with osteoporosis, respectively. The lumbar spine and femoral neck BMD and the CTMean of the proximal humerus were higher in males than females with proximal humeral fractures (P < 0.05). This gender difference was also found in the osteoporotic patient population (P < 0.05). The Spearman rank correlation method showed that the lumbar spine and femoral neck BMD was closely related to the proximal humeral CTMean in males (r = 0.877, P = 0.000; r = 0.832, P = 0.000; respectively) and females (r = 0.806, P = 0.000; r = 0.616, P = 0.000; respectively) with proximal humeral fractures, as well as osteoporotic male (r = 0.745, P = 0.000; r = 0.575, P = 0.000; respectively) and female (r = 0.613, P = 0.000; r = 0.629, P = 0.000; respectively) patients. CONCLUSIONS: The CT value of the proximal humerus is a rapid and accurate method by which bone quality can be assessed in elderly patients with proximal humeral fractures. Moreover, the CT value of the proximal humerus is an alternative measurement of BMD that can guide surgeons in selecting the appropriate internal fixation material.

Population genetic analysis of the Plasmodium falciparum erythrocyte binding antigen-175 (EBA-175) gene in Equatorial Guinea.

BACKGROUND: Plasmodium falciparum erythrocyte binding antigen-175 (PfEBA-175) is a candidate antigen for a blood-stage malaria vaccine, while various polymorphisms and dimorphism have prevented to development of effective vaccines based on this gene. This study aimed to investigate the dimorphism of PfEBA-175 on both the Bioko Island and continent of Equatorial Guinea, as well as the genetic polymorphism and natural selection of global PfEBA-175. METHODS: The allelic dimorphism of PfEBA-175 region II of 297 bloods samples from Equatorial Guinea in 2018 and 2019 were investigated by nested polymerase chain reaction and sequencing. Polymorphic characteristics and the effect of natural selection were analyzed using MEGA 7.0, DnaSP 6.0 and PopART programs. Protein function prediction of new amino acid mutation sites was performed using PolyPhen-2 and Foldx program. RESULTS: Both Bioko Island and Bata district populations, the frequency of the F-fragment was higher than that of the C-fragment of PfEBA-175 gene. The PfEBA-175 of Bioko Island and Bata district isolates showed a high degree of genetic variability and heterogeneity, with π values of 0.00407 & 0.00411 and Hd values of 0.958 & 0.976 for nucleotide diversity, respectively. The values of Tajima's D of PfEBA-175 on Bata district and Bioko Island were 0.56395 and - 0.27018, respectively. Globally, PfEBA-175 isolates from Asia were more diverse than those from Africa and South America, and genetic differentiation quantified by the fixation index between Asian and South American countries populations was significant (FST > 0.15, P < 0.05). A total of 310 global isolates clustered in 92 haplotypes, and only one cluster contained isolates from three continents. The mutations A34T, K109E, D278Y, K301N, L305V and D329N were predicted as probably damaging. CONCLUSIONS: This study demonstrated that the dimorphism of F-fragment PfEBA-175 was remarkably predominant in the study area. The distribution patterns and genetic diversity of PfEBA-175 in Equatorial Guinea isolates were similar another region isolates. And the levels of recombination events suggested that natural selection and intragenic recombination might be the main drivers of genetic diversity in global PfEBA-175. These results have important reference value for the development of blood-stage malaria vaccine based on this antigen.

Pathoanatomy and Injury Mechanism of Typical Maisonneuve Fracture.

OBJECTIVE: Maisonneuve fracture is a special type of injury which are rare in clinic. The manifestation of such fractures is variable. The aim of this study is to describe the pathoanatomical features of typical Maisonneuve fracture on the basis of radiographs, computed tomography (CT) scans, magnetic resonance imaging (MRI), and intraoperative exploration findings, and to investigate the injury mechanism of this variety. METHODS: The data of 41 patients with Maisonneuve fracture from April 2014 to September 2019 were retrospectively analyzed. There were 32 males and nine females, the average age was 37.9 years (range, 18 to 61 years), the fractures occurred on the left side in 20 patients and on the right side in 21 patients. The cause of injuries were traffic accident in five patients, sprain injury in 20 patients, and falling injury from height in 16 patients. All patients underwent posteroanterior and lateral X-ray examinations of the ankle and calf. CT scan of the ankle was performed in 38 patients, including three-dimensional reconstruction in 33 patients. MRI examination of the ankle and calf was performed in 28 and five patients, respectively. Forty patients were treated with open reduction and internal fixation. The features of proximal fibular fracture, injuries of the medial and posterior structures of the ankle, injuries of the anterior inferior tibiofibular ligament and the interosseous membrane were recorded and analyzed. RESULTS: Forty-one patients had proximal one-third fractures of the fibula including six patients with fracture involving the fibular neck, 30 with proximal one-third fractures of the fibular shaft, and five with proximal-medial one-third junction fracture of the fibular shaft. Thirty-five patients (35/41, 85.37%) with injury of posterior structures, 34 patients had posterior malleolar fracture (34/41, 82.93%), and one patient had posterior inferior tibiofibular ligament rupture (1/41, 2.44%). There were 20 patients with type I fracture, four patients with type II fracture, and 10 patients with type III fracture according to the Haraguchi classification of posterior malleolus fracture. The fracture of the medial malleolus was in 30 patients (30/41, 73.17%), rupture of the deltoid ligament was in 10 patients (10/41, 24.39%), and medial structures intact were in one patient (1/41, 2.44%). All 41 patients had injury of the anterior inferior tibiofibular ligament. CONCLUSIONS: Maisonneuve fracture is characterized by fractures of the proximal fibula and the complete rupture of the anterior inferior tibiofibular ligament. Pronation-external rotation is the main injury mechanism. The manifestations of typical Maisonneuve fracture including that the fibular fracture located in proximal one-third diaphysis and the fracture line was from anterosuperior to posteroinferior.

Genetic polymorphism of Plasmodium falciparum circumsporozoite protein on Bioko Island, Equatorial Guinea and global comparative analysis.

BACKGROUND: Plasmodium falciparum circumsporozoite protein (PfCSP) is a potential malaria vaccine candidate, but various polymorphisms of the pfcsp gene among global P. falciparum population become the major barrier to the effectiveness of vaccines. This study aimed to investigate the genetic polymorphisms and natural selection of pfcsp in Bioko and the comparison among global P. falciparum population. METHODS: From January 2011 to December 2018, 148 blood samples were collected from P. falciparum infected Bioko patients and 96 monoclonal sequences of them were successfully acquired and analysed with 2200 global pfcsp sequences mined from MalariaGEN Pf3k Database and NCBI. RESULTS: In Bioko, the N-terminus of pfcsp showed limited genetic variations and the numbers of repetitive sequences (NANP/NVDP) were mainly found as 40 (35%) and 41 (34%) in central region. Most polymorphic characters were found in Th2R/Th3R region, where natural selection (p > 0.05) and recombination occurred. The overall pattern of Bioko pfcsp gene had no obvious deviation from African mainland pfcsp (Fst = 0.00878, p < 0.05). The comparative analysis of Bioko and global pfcsp displayed the various mutation patterns and obvious geographic differentiation among populations from four continents (p < 0.05). The global pfcsp C-terminal sequences were clustered into 138 different haplotypes (H_1 to H_138). Only 3.35% of sequences matched 3D7 strain haplotype (H_1). CONCLUSIONS: The genetic polymorphism phenomena of pfcsp were found universal in Bioko and global isolates and the majority mutations located at T cell epitopes. Global genetic polymorphism and geographical characteristics were recommended to be considered for future improvement of malaria vaccine design.

Clinical Outcomes of the Central Third Patellar Tendon Versus Four-strand Hamstring Tendon Autograft Used for Anterior Cruciate Ligament Reconstruction: A Systematic Review and Subgroup Meta-analysis of Randomized Controlled Trials.

BACKGROUND: The most frequently used auto-grafts for ACL reconstruction (ACLR) are bone-patellar tendon-bone (BPTB) and four-strand hamstring tendon (4S-HT), but significant controversy exists about which graft is better. This study aimed to compare the knee outcomes following ACLR with BPTB and 4S-HT autografts. METHODS: Subgroup meta-analyses were performed basing on available randomised controlled trials (RCTs) according to different follow-up intervals. 23 RCTs were eligible for inclusion, involving 933 participants in each treatment group. RESULTS: Only short-term (≤2 years) knee anteroposterior and rotational stability were significantly poorer with 4S-HT when compared to BPTB autograft, as judged by side-to-side difference on knee laxity (WMD=-0.50, 95%CI -0.81~-0.18, p=0.002) and pivot-shift test (OR=0.58, 95%CI 0.39~0.88, p=0.010), respectively. The IKDC objective grade was evident to be in favour of 4S-HT group in mid-term (3-5 years) follow-up (OR=0.63, 95%CI 0.43~0.92, p=0.017). Several donor-site related complications, including anterior knee pain, pain with kneeling and extension deficit, were more frequent in BPTB autograft group, while lower short-term iskinetic peak flexion torques both at 60°/S (WMD=8.93, 95%CI 7.88~9.99, p<0.001) and 240°/S (WMD=11.63, 95%CI 9.92~13.34, p<0.001) were caused by HT harvesting. CONCLUSION: BPTB was associated with inferior mid- to long-term (>5 years) knee functional outcomes, and increased frequency of donor-site complications. In contrast, only short-term knee laxity was increased for 4S-HT autograft, which is expected to be improved by providing more conservative rehabilitation protocol and aperture fixation methods.

Overexpression of suppressors of cytokine signaling 1 regulate the proliferation and differentiation of rat-derived neural stem cells.

Neural stem cells are a reliable resource in various neural tissue repair and neurodegenerative diseases. Increasing evidence has demonstrated that Suppressor of cytokine signaling proteins (SOCS) was involved in the nervous system development. The universality and diversity of SOCS also suggested their important roles in neurogenesis and nerve regeneration. In this study, we employed a lentiviral vector to investigate the impacts of overexpression SOCS1 on the proliferation and differentiation of rat-derived NSCs. Cells infected with LV-EGFP-SOCS1 showed a prominent increased cell number, diameter, and metabolic activity compared with other groups. Immunofluorescence analysis revealed the proportion of cells positive for microtubule associated protein-2 (MAP2) or myelin basic protein (MBP) was significantly increased in LV-EGFP-SOCS1 group while the proportion of glial fibrillary acidic protein (GFAP)-positive cells in LV-EGFP-SOCS1 group was significantly decreased compare to LV-EGFP and PBS group. Moreover, Western blot results were consistent with immunofluorescence results which indicated that overexpression of SOCS1 could promote neuronal and oligodendrocyte differentiations of NSCs but inhibit astrocyte differentiation of NSCs. In conclusion, our findings provided evidence that SOCS1 could promote the proliferation of NSCs and affect the differentiation of NSCs, providing a potential target for NSCs transplantation strategies.

Teeth extraction with endotracheal intubation under general anesthesia in special needs patients-a retrospective analysis / 口腔疾病防治

Objective@#To discuss the demand and security of tooth extraction under general anesthesia with endotracheal intubation for the special needs patients.@*Methods@#From January 2014 to December 2015, the cases of tooth extraction under general anesthesia were collected to analyse the demand and security of tooth extraction with general anesthesia.@*Results@#54 patients were recruited in the study in which 11 were with serious limitation of mouth opening, 10 were with serious cardiovascular disease risk, 2 were with history of epilepsy, 13 were with serious dental phobia, and 18 were incoordination patients. All the operations were performed successfully and safely, and all the scores of post anesthetic discharge scoring system exceeded 9 points. No developed complications were showed in 1 day, 1 week, 1 month follow-up.@*Conclusion @#Tooth extraction under general anesthesia with endotracheal intubation is a safe way for special needs patients.

Three-dimensional Computer-assisted Modeling of Talus Morphology in Chinese Patients.

OBJECTIVE: To provide more accurate reference data for the assessment and treatment of talar injuries by constructing 3-D computer-assisted models of the talus and comparing them with reference data obtained from measurements on cadaver specimens. METHODS: Three-dimensional talus models were constructed from CT data recorded for healthy Chinese volunteers using SuperImage Orthopedics software. Structural variables such as length, width, height and volume of talus were compared using the Fisher least significant difference test to determine the significance of bilateral or sex-specific differences in the study cohort. RESULTS: Measurement data were normally distributed. No significant difference between the left and right talus in either men or women was identified for any measurement (P > 0.05). The bilateral mean volume of the talus in men (37.87 ± 6.69 mm) was significantly larger than that in women (26.95 ± 5.73 mm; P < 0.05). Although the dimensions of most of the structural features and articular surfaces of the talus were significantly larger in men than in women (P < 0.05), no significant differences in the angles of the talar neck and head were observed between men and women in our cohort (P > 0.05). CONCLUSION: Our method of 3-D model construction provided precise measurements of the structural features of the talus. The talar dimensions in our Chinese study cohort differ from those previously reported for people of different ethnic groups. Our models should provide accurate reference data for constructing models based on CT images for the assessment and treatment of talar injuries in Chinese patients.

[Comparison of two different flap designs in removal of impacted wisdom tooth].

PURPOSE: The purpose of this study was to compare the effect of two different flap designs on surgical removal of impacted mandibular third molars. METHODS: Four hundred patients who required removal of impacted mandibular third molars were included in the study. They were divided into group A and group B randomly. Patients in group A received distal incision flap and group B underwent angular incision flap. The effect of flap design on surgical time, incidence of dry socket, pain, swelling and trismus was evaluated postoperatively. Data analysis was carried out with SPSS 13.0 software package. RESULTS: The surgical time was longer in group A than in group B 3 days postoperatively. Facial swelling and trismus were less in group A than in group B 3 days postoperatively. There was no significant difference in two groups 7 days postoperatively. CONCLUSIONS: The distal incision flap design can release facial swelling and trismus in surgical removal of impacted mandibular third molars.

Overexpression of suppressors of cytokine signaling 1 promotes the neuronal differentiation of C17.2 neural stem cells.

OBJECTIVE: To investigate the role and mechanism of suppressor of cytokine signaling 1 (SOCS1) in the regulation and differentiation of C17.2 neural stem cells (NSCs). METHODS: In this study, lentiviral (LV)-SOCS1-enhanced green fluorescent protein (EGFP) was constructed and transfected into C17.2 NSCs. There were three groups of C17.2 NSCs: LV-SOCS1-EGFP, LV-EGFP, and phosphate-buffered saline (PBS). The expression levels of microtubule-associated protein 2 (MAP2), glial fibrillary acidic protein (GFAP), myelin basic protein (MBP), nestin, and ß-tubulin III in C17.2 NSCs were analyzed by reverse transcription-polymerase chain reaction (RT-PCR), immunocytochemistry, and western blot. In addition, the phosphorylation level of Jaks/Stats family members in C17.2 NSCs were analyzed by western blot. Moreover, the morphological changes of C17.2 NSCs after transfection were observed by light microscopy. RESULTS: The gene expression of MAP2 increased significantly and the gene expression of nestin decreased significantly in C17.2 NSCs transfected with LV-SOCS1-EGFP. Some C17.2 NSCs underwent prominent neuronal morphological changes and expressed ß-tubulin III after LV-SOCS1-EGFP transfection. The number of positive cells for ß-tubulin III immunocytochemical staining and ß-tubulin III protein expression in C17.2 NSCs after LV-SOCS1-EGFP transfection were both more than those after LV-EGFP transfection or PBS treatment. The phosphorylation levels of Jak2 and Stat3 but not Jak3 in C17.2 NSCs were inhibited by SOCS1 overexpression. CONCLUSION: Overexpression of SOCS1 in C17.2 NSCs promotes the generation of neurons, which is likely mediated by the negative feedback inhibition of Jak2 and Stat3. This study is the first to provide evidence that SOCS1 is involved in the regulation of neurogenesis.

Isotopic tracing for calculating the surface density of arginine-glycine-aspartic acid-containing peptide on allogeneic bone.

OBJECTIVE: To investigate the feasibility of determining the surface density of arginine-glycine-aspartic acid (RGD) peptides grafted onto allogeneic bone by an isotopic tracing method involving labeling these peptides with (125) I, evaluating the impact of the input concentration of RGD peptides on surface density and establishing the correlation between surface density and their input concentration. METHODS: A synthetic RGD-containing polypeptide (EPRGDNYR) was labeled with (125) I and its specific radioactivity calculated. Reactive solutions of RGD peptide with radioactive (125) I-RGD as probe with input concentrations of 0.01 mg/mL, 0.10 mg/mL, 0.50 mg/mL, 1.00 mg/mL, 2.00 mg/mL and 4.00 mg/mL were prepared. Using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide as a cross-linking agent, reactions were induced by placing allogeneic bone fragments into reactive solutions of RGD peptide of different input concentrations. On completion of the reactions, the surface densities of RGD peptides grafted onto the allogeneic bone fragments were calculated by evaluating the radioactivity and surface areas of the bone fragments. The impact of input concentration of RGD peptides on surface density was measured and a curve constructed. RESULTS: Measurements by a radiodensity γ-counter showed that the RGD peptides had been labeled successfully with (125) I. The allogeneic bone fragments were radioactive after the reaction, demonstrating that the RGD peptides had been successfully grafted onto their surfaces. It was also found that with increasing input concentration, the surface density increased. CONCLUSION: It was concluded that the surface density of RGD peptides is quantitatively related to their input concentration. With increasing input concentration, the surface density gradually increases to saturation value.

[Prosthetic replacement of condylar head for management of traumatic temporomandibular joint ankylosis].

OBJECTIVE: To preliminarily evaluate the method of using titanium condylar protheses in management of traumatic temporomandibular joint ankylosis. METHODS: Between August 2006 and April 2008, titanium condylar replacement was performed in 5 male patients. Preoperative CT datum of patient was obtained and a resin model was then produced and used as a reference to select a suitable titanium condyle for reconstruction of the joint. In the operation, the bony ankylosis was removed. According to the preoperation planning, the selected prosthesis was inserted and fixed to the distal mandibular segment. The results were assessed by means of examinations and measurements postoperatively and during follow-up. RESULTS: The 5 patients received alloplastic replacement of 6 condyles. Three patients were under follow-up and follow-up time ranged from 8 months to 2 years and 6 months. The mean mouth opening was 30 mm. Two patients had good occlusion and one patient developed a slight open bite. CONCLUSIONS: Prosthetic condylar replacement can provide a choice for management of traumatic temporomandibular joint ankylosis.