Pro-CRISPR PcrIIC1-associated Cas9 system for enhanced bacterial immunity.

The CRISPR system is an adaptive immune system found in prokaryotes that defends host cells against the invasion of foreign DNA1. As part of the ongoing struggle between phages and the bacterial immune system, the CRISPR system has evolved into various types, each with distinct functionalities2. Type II Cas9 is the most extensively studied of these systems and has diverse subtypes. It remains uncertain whether members of this family can evolve additional mechanisms to counter viral invasions3,4. Here we identify 2,062 complete Cas9 loci, predict the structures of their associated proteins and reveal three structural growth trajectories for type II-C Cas9. We found that novel associated genes (NAGs) tended to be present within the loci of larger II-C Cas9s. Further investigation revealed that CbCas9 from Chryseobacterium species contains a novel ß-REC2 domain, and forms a heterotetrameric complex with an NAG-encoded CRISPR-Cas-system-promoting (pro-CRISPR) protein of II-C Cas9 (PcrIIC1). The CbCas9-PcrIIC1 complex exhibits enhanced DNA binding and cleavage activity, broader compatibility for protospacer adjacent motif sequences, increased tolerance for mismatches and improved anti-phage immunity, compared with stand-alone CbCas9. Overall, our work sheds light on the diversity and 'growth evolutionary' trajectories of II-C Cas9 proteins at the structural level, and identifies many NAGs-such as PcrIIC1, which serves as a pro-CRISPR factor to enhance CRISPR-mediated immunity.

Thousands of conductance levels in memristors integrated on CMOS.

Neural networks based on memristive devices1-3 have the ability to improve throughput and energy efficiency for machine learning4,5 and artificial intelligence6, especially in edge applications7-21. Because training a neural network model from scratch is costly in terms of hardware resources, time and energy, it is impractical to do it individually on billions of memristive neural networks distributed at the edge. A practical approach would be to download the synaptic weights obtained from the cloud training and program them directly into memristors for the commercialization of edge applications. Some post-tuning in memristor conductance could be done afterwards or during applications to adapt to specific situations. Therefore, in neural network applications, memristors require high-precision programmability to guarantee uniform and accurate performance across a large number of memristive networks22-28. This requires many distinguishable conductance levels on each memristive device, not only laboratory-made devices but also devices fabricated in factories. Analog memristors with many conductance states also benefit other applications, such as neural network training, scientific computing and even 'mortal computing'25,29,30. Here we report 2,048 conductance levels achieved with memristors in fully integrated chips with 256 × 256 memristor arrays monolithically integrated on complementary metal-oxide-semiconductor (CMOS) circuits in a commercial foundry. We have identified the underlying physics that previously limited the number of conductance levels that could be achieved in memristors and developed electrical operation protocols to avoid such limitations. These results provide insights into the fundamental understanding of the microscopic picture of memristive switching as well as approaches to enable high-precision memristors for various applications. Fig. 1 HIGH-PRECISION MEMRISTOR FOR NEUROMORPHIC COMPUTING.: a, Proposed scheme of the large-scale application of memristive neural networks for edge computing. Neural network training is performed in the cloud. The obtained weights are downloaded and accurately programmed into a massive number of memristor arrays distributed at the edge, which imposes high-precision requirements on memristive devices. b, An eight-inch wafer with memristors fabricated by a commercial semiconductor manufacturer. c, High-resolution transmission electron microscopy image of the cross-section view of a memristor. Pt and Ta serve as the bottom electrode (BE) and top electrode (TE), respectively. Scale bars, 1 µm and 100 nm (inset). d, Magnification of the memristor material stack. Scale bar, 5 nm. e, As-programmed (blue) and after-denoising (red) currents of a memristor are read by a constant voltage (0.2 V). The denoising process eliminated the large-amplitude RTN observed in the as-programmed state (see Methods). f, Magnification of three nearest-neighbour states after denoising. The current of each state was read by a constant voltage (0.2 V). No large-amplitude RTN was observed, and all of the states can be clearly distinguished. g, An individual memristor on the chip was tuned into 2,048 resistance levels by high-resolution off-chip driving circuitry, and each resistance level was read by a d.c. voltage sweeping from 0 to 0.2 V. The target resistance was set from 50 µS to 4,144 µS with a 2-µS interval between neighbouring levels. All readings at 0.2 V are less than 1 µS from the target conductance. Bottom inset, magnification of the resistance levels. Top inset, experimental results of an entire 256 × 256 array programmed by its 6-bit on-chip circuitry into 64 32 × 32 blocks, and each block is programmed into one of the 64 conductance levels. Each of the 256 × 256 memristors has been previously switched over one million cycles, demonstrating the high endurance and robustness of the devices.

The adaptor protein 14-3-3zeta modulates intestinal immunity and aging in Drosophila.

The proteins that coordinate the complex transcriptional networks of aging have not been completely documented. Protein 14-3-3zeta is an adaptor protein that coordinates signaling and transcription factor networks, but its function in aging is not fully understood. Here, we showed that the protein expression of 14-3-3zeta gradually increased during aging. High levels of 14-3-3zeta led to shortened lifespan and imbalance of intestinal immune homeostasis in Drosophila, but the decrease in 14-3-3zeta protein levels by RNAi was able to significantly promote the longevity and intestinal immune homeostasis of fruit flies. Importantly, we demonstrate that adult-onset administration of TIC10, a compound that reduces the aging-related AKT and extracellular signal-regulated kinase (ERK) signaling pathways, rescues the shortened lifespan of 14-3-3zeta-overexpressing flies. This finding suggests that 14-3-3zeta plays a critical role in regulating the aging process. Our study elucidates the role of 14-3-3zeta in natural aging and provides the rationale for subsequent 14-3-3zeta-based antiaging research.

High-Throughput CRISPR/Cas9 Mutagenesis Streamlines Trait Gene Identification in Maize.

Maize (Zea mays) is one of the most important crops in the world. However, few agronomically important maize genes have been cloned and used for trait improvement, due to its complex genome and genetic architecture. Here, we integrated multiplexed CRISPR/Cas9-based high-throughput targeted mutagenesis with genetic mapping and genomic approaches to successfully target 743 candidate genes corresponding to traits relevant for agronomy and nutrition. After low-cost barcode-based deep sequencing, 412 edited sequences covering 118 genes were precisely identified from individuals showing clear phenotypic changes. The profiles of the associated gene-editing events were similar to those identified in human cell lines and consequently are predictable using an existing algorithm originally designed for human studies. We observed unexpected but frequent homology-directed repair through endogenous templates that was likely caused by spatial contact between distinct chromosomes. Based on the characterization and interpretation of gene function from several examples, we demonstrate that the integration of forward and reverse genetics via a targeted mutagenesis library promises rapid validation of important agronomic genes for crops with complex genomes. Beyond specific findings, this study also guides further optimization of high-throughput CRISPR experiments in plants.

Low-Light Image Enhancement Based on Constraint Low-Rank Approximation Retinex Model.

Images captured in a low-light environment are strongly influenced by noise and low contrast, which is detrimental to tasks such as image recognition and object detection. Retinex-based approaches have been continuously explored for low-light enhancement. Nevertheless, Retinex decomposition is a highly ill-posed problem. The estimation of the decomposed components should be combined with proper constraints. Meanwhile, the noise mixed in the low-light image causes unpleasant visual effects. To address these problems, we propose a Constraint Low-Rank Approximation Retinex model (CLAR). In this model, two exponential relative total variation constraints were imposed to ensure that the illumination is piece-wise smooth and that the reflectance component is piece-wise continuous. In addition, the low-rank prior was introduced to suppress the noise in the reflectance component. With a tailored separated alternating direction method of multipliers (ADMM) algorithm, the illumination and reflectance components were updated accurately. Experimental results on several public datasets verify the effectiveness of the proposed model subjectively and objectively.

14-3-3 epsilon is an intracellular component of TNFR2 receptor complex and its activation protects against osteoarthritis.

OBJECTIVES: Osteoarthritis (OA) is the most common joint disease; however, the indeterminate nature of mechanisms by which OA develops has restrained advancement of therapeutic targets. TNF signalling has been implicated in the pathogenesis of OA. TNFR1 primarily mediates inflammation, whereas emerging evidences demonstrate that TNFR2 plays an anti-inflammatory and protective role in several diseases and conditions. This study aims to decipher TNFR2 signalling in chondrocytes and OA. METHODS: Biochemical copurification and proteomics screen were performed to isolate the intracellular cofactors of TNFR2 complex. Bulk and single cell RNA-seq were employed to determine 14-3-3 epsilon (14-3-3ε) expression in human normal and OA cartilage. Transcription factor activity screen was used to isolate the transcription factors downstream of TNFR2/14-3-3ε. Various cell-based assays and genetically modified mice with naturally occurring and surgically induced OA were performed to examine the importance of this pathway in chondrocytes and OA. RESULTS: Signalling molecule 14-3-3ε was identified as an intracellular component of TNFR2 complexes in chondrocytes in response to progranulin (PGRN), a growth factor known to protect against OA primarily through activating TNFR2. 14-3-3ε was downregulated in OA and its deficiency deteriorated OA. 14-3-3ε was required for PGRN regulation of chondrocyte metabolism. In addition, both global and chondrocyte-specific deletion of 14-3-3ε largely abolished PGRN's therapeutic effects against OA. Furthermore, PGRN/TNFR2/14-3-3ε signalled through activating extracellular signal-regulated kinase (ERK)-dependent Elk-1 while suppressing nuclear factor kappa B (NF-κB) in chondrocytes. CONCLUSIONS: This study identifies 14-3-3ε as an inducible component of TNFR2 receptor complex in response to PGRN in chondrocytes and presents a previously unrecognised TNFR2 pathway in the pathogenesis of OA.

ALK7 Promotes Vascular Smooth Muscle Cells Phenotypic Modulation by Negative Regulating PPARγ Expression.

As a receptor for transforming growth factor-ß, nodal and activin, activin receptor-like kinase 7 (ALK7) previously acts as a suppressor of tumorigenesis and metastasis, which has emerged to play a key role in cardiovascular diseases. However, the potential effect and molecular mechanism of ALK7 on vascular smooth muscle cells' (VSMCs) phenotypic modulation have not been investigated. Using cultured mouse VSMCs with platelet-derived growth factor-BB administration, we observed that ALK7 showed a significantly increased expression in VSMCs accompanied by decreased VSMCs differentiation marker genes. Loss-of-function study demonstrated that ALK7 knockdown inhibited platelet-derived growth factor-BB-induced VSMCs phenotypic modulation characterized by increased VSMCs differentiation markers, reduced proliferation, and migration of VSMCs. Such above effects were reversed by ALK7 overexpression. Notably, we noticed that ALK7 silencing dramatically enhanced PPARγ expression, which was required for the attenuated effect of ALK7 knockdown on VSMCs phenotypic modulation. Collected, we identified that ALK7 acted as a novel and positive regulator for VSMCs phenotypic modulation partially through inactivation of PPARγ, which suggested that neutralization of ALK7 might act as a promising therapeutic strategy of intimal hyperplasia.

Long noncoding RNAs C2dat1 enhances vascular smooth muscle cell proliferation and migration by targeting MiR-34a-5p.

Deregulated proliferation of vascular smooth muscle cells (VSMCs) is one common phenomenon of atherosclerosis progression. Long noncoding RNAs (lncRNAs) are one group of noncoding RNAs that play essential roles in many cell biological processes, including cell development, growth, and migration. However, the role of a novel calcium/calmodulin-dependent protein kinase type II subunit delta (CAMK2D)-associated lncRNA, CAMK2D-associated transcript 1 (C2dat1), in VSMCs is still uncovered. In this study, we showed that the expression level of C2dat1 was higher in coronary artery disease (CAD) tissues than in normal arterial tissues and the C2dat1 expression level was upregulated in the proliferating VSMC after being treated with PDGF-bb or TNF-α. In addition, we indicated that overexpression of C2dat1 promoted VSMC growth and enhanced proliferating cell nuclear antigen (PCNA) expression in VSMC. Moreover, ectopic expression of C2dat1 increased VSMC migration. Furthermore, we showed that elevated expression of C2dat1 suppressed microRNA-34a (miR-34a) expression and promoted sirtuin 1 (SIRT1) expression, which was a direct target gene of miR-34a. We demonstrated that the expression level of miR-34a was lower in CAD tissues than in normal arterial tissues and the expression of miR-34a was negatively correlated with C2dat1 expression. Restored expression of C2dat1 increased VSMC proliferation and migration through promoting SIRT1 expression. These data suggested that lncRNA C2dat1 might be a potential therapeutic target to promote VSMC growth and migration in CAD.

Isolated Decompression for Transverse Sacral Fractures with Cauda Equina Syndrome.

BACKGROUND The purpose of this study was to evaluate the clinical outcomes of isolated decompression for patients with transverse sacral fractures and cauda equina syndrome, which have been rarely reported before. MATERIAL AND METHODS Twelve neurological impaired patients with transverse sacral fracture from January 2010 to March 2017 treated in our institution were evaluated. All patients went through isolated decompression and were followed for a minimum of 12 months. Fracture causes, classifications, associated injury, radiologic results, clinical outcomes using the Majeed index, and neurological outcomes using the Gibbons criteria were evaluated. RESULTS Motor vehicle accidents and falling injuries were the major causes of trauma. The average time from trauma to surgery was 89.8 days. Eleven patients underwent laminectomy with no more than 3 segments resected and 1 patient had S1-S4 excised. Three patients with fracture involving the lumbopelvic joint had L5 laminectomy. All patients achieved bony union, with 7 patients (63.6%) showing satisfactory pelvic outcome. Average Gibbons scores improved from 2.8 to 1.9 at 18-month average follow-up, but most patients were left with residual pain. No surgical-related complications were seen in any patients. CONCLUSIONS Isolated decompression can be considered for patients who present a stable sacrum with non-displaced fracture or an old fracture that shows fracture healing. Favorable pelvic outcomes and neurological recovery, along with acceptable stability, can be acquired.

Management and outcome of pelvic fracture associated with vaginal injuries: a retrospective study of 25 cases.

BACKGROUND: Pelvic ring fractures associated with vaginal injuries were rarely reported due to low incidence. The displaced segments of pelvic ring may increase the risk of vaginal injury. The aim of this retrospective study was to evaluate the correlation between pelvic fracture and vaginal injury. METHODS: We conducted a retrospective review of 25 patients with pelvic fractures associated with vaginal injury treated at our institution. The medical records of these patients were collected and 24 patients were followed-up for 10-36 months. RESULTS: All patients suffered anterior pelvic ring fracture. Young-Burgess fracture classification and compromised pubic symphysis were related to severity of vaginal injury. Gauze packing was done in 6 patients and 18 patients received surgical repair. Infection occurred in 6 patients, among them 4 were due to delayed diagnosis. Factors associated with pelvic outcome were age, urethral injury, and infection. Four patients suffered pain in sexual intercourse but no influence factor found correlated to sexual function. CONCLUSION: VS type pelvic fracture and compromised pubic symphysis were related to higher severity of vaginal injury. Disruption of anterior ring and an unstable pelvic ring caused by forces on coronary and axial plane may increase the risk of vaginal injury. TRIAL REGISTRATION: ChiCTR1900020540 . Registered 28 January 2019. Retrospectively registered. TRIAL REGISTRY: Chinese Clinical Trial Registry.

External fixation-assisted reduction for the treatment of neglected hip dislocations with limb length discrepancy: a retrospective study of 13 cases.

BACKGROUND: The purpose of this study was to evaluate a new method for treating neglected hip dislocation with limb length discrepancy by using external fixation-assisted pre-reduction. METHODS: Thirteen patients admitted between January 2010 to February 2018 with a mean duration from injury to surgery of 5.0 ± 2.1 months and an average preoperative leg-length discrepancy of 7.7 ± 2.3 cm were enrolled in this study. The dislocation and associated acetabular fracture type, clinical outcomes and residual limb length discrepancy were evaluated. RESULTS: All patients had posterior dislocations, and nine patients presented with acetabular fractures and were followed-up for at least 12 months. The average traction duration of external fixators was 28.8 ± 8.0 days and all patients received second-stage open reduction and internal fixation. Six patients showed residual limb length discrepancy within 2 cm. Patients showed significant improvement in hip function and pain relief. Complications including avascular femoral head necrosis and osteoarthritis occurred in three patients. CONCLUSION: Effective correction of limb length discrepancy and improved function were observed in patients with neglected hip dislocations and limb equality using traction by external fixation combined with second-stage open reduction. Further follow-up is required to determine long-term outcomes.

14-3-3 Proteins Are on the Crossroads of Cancer, Aging, and Age-Related Neurodegenerative Disease.

14-3-3 proteins are a family of conserved regulatory adaptor molecules which are expressed in all eukaryotic cells. These proteins participate in a variety of intracellular processes by recognizing specific phosphorylation motifs and interacting with hundreds of target proteins. Also, 14-3-3 proteins act as molecular chaperones, preventing the aggregation of unfolded proteins under conditions of cellular stress. Furthermore, 14-3-3 proteins have been shown to have similar expression patterns in tumors, aging, and neurodegenerative diseases. Therefore, we put forward the idea that the adaptor activity and chaperone-like activity of 14-3-3 proteins might play a substantial role in the above-mentioned conditions. Interestingly, 14-3-3 proteins are considered to be standing at the crossroads of cancer, aging, and age-related neurodegenerative diseases. There are great possibilities to improve the above-mentioned diseases and conditions through intervention in the activity of the 14-3-3 protein family.

Clinical significance of three-dimensional skeleton-arterial model in the management of delayed reconstruction of acetabular fractures.

BACKGROUND: Delayed reconstruction of acetabular fractures remains a challenging task for orthopedists because of malunion, fracture line absorption, and scar formation. Accurate osteotomy, interfragmentary release, and proper adaptation of plates are keys to successful surgery. Prevention of superior gluteal artery (SGA) injury induced by cleaning of the osteotylus and reduction of the sciatic notch is also important. Therefore, sufficient preoperative planning is essential. However, traditional planning methods do not readily provide direct visual and tactile feedback to surgeons. Rapid prototyping (RP) models have provided new opportunities in the preoperative planning of delayed reconstruction of acetabular fractures. We hypothesized that a three-dimensional (3D) skeleton-arterial model would improve both preoperative planning in the management of fractures and arteries and intraoperative assistance during delayed reconstruction of complex acetabular fractures. METHODS: Eight patients were enrolled in this study. Data on the skeleton and arteries were obtained from computed tomography and angiography scans and used to produce RP models. Preoperative surgical planning and intraoperative assistance were performed using these models as references. RESULTS: All 3D skeleton-arterial models were extremely accurate. Reduction and fixation were performed programmatically and smoothly, and management of the SGA was reliably executed according to a thorough preoperative plan. The mean surgical time and intraoperative blood loss were 224.4 min and 1250 ml, respectively. Among the eight patients, four underwent anatomic reduction and five had excellent functional outcomes at the final follow-up. No significant complications occurred. CONCLUSIONS: This 3D skeleton-arterial model is helpful for orthopedists in preoperative planning and intraoperative assistance.

Salvage of Iatrogenic Sciatic Nerve Injury Caused by Operatively Treated Acetabular Fractures: Two Cases and Literature Review.

BACKGROUND: While sciatic nerve injury has been described as a complication of acetabular fractures, iatrogenic nerve injury remains sparsely reported. This study aims to assess iatrogenic sciatic nerve injuries occurring during acetabular fracture surgery, tracking their neurological recovery and clinical outcomes, and investigating any correlation between recovery and the severity of neurologic injury to facilitate physicians in providing prediction of prognosis. CASE PRESENTATION: We present two cases of male patients, aged 56 and 22, who developed sciatic palsy due to iatrogenic nerve injury during acetabular fracture surgery. Iatrogenic sciatic nerve injury resulted from operatively treated acetabular fractures. Surgical exploration, involving internal fixation removal and nerve decompression, successfully alleviated symptoms in both cases postoperatively. At the latest follow-up, one patient achieved full recovery with excellent function, while the other exhibited residual deficits at the L5/S1 root level along with minimal pain. CONCLUSION: Sciatic nerve injury likely stemmed from reduction techniques and internal fixation procedures for the posterior column, particularly when performed with the hip flexed, thereby placing tension on the sciatic nerve. Our case reports underscore the significance of liberal utilization of electrophysiologic examinations and intraoperative monitoring for the prediction of prognosis. Surgical exploration, encompassing internal fixation removal and nerve decompression, represents an effective intervention for resolving sciatic palsy, encompassing both sensory neuropathy and motor symptoms.

P2/O3 Biphasic Cathode Material through Magnesium Substitution for Sodium-Ion Batteries.

P2-type Fe-Mn-based oxides offer excellent discharge specific capacity and are as affordable as typical layered oxide cathode materials for sodium-ion batteries (SIBs). After Cu modification, though they can improve the cycling performance and air stability, the discharge specific capacity will be reduced. Considering the complementary nature of biphasic phases in electrochemistry, hybridizing P2/O3 hybrid phases can enhance both the storage performance of the battery and specific capacity. Herein, a hybrid phase composite with high capacity and good cycle performance is deliberately designed and successfully prepared by controlling the amount of Mg doping in the layered oxide. It has been found that the introduction of Mg can activate anion redox in the oxide layer, resulting in a significant increase in the specific discharge capacity of the material. Meanwhile, the dual-phase structure can produce an interlocking effect, thus effectively alleviating structure strain. The degradation of cycling performance caused by structural damage during the high-voltage charging and discharging process is clearly mitigated. The results show that the specific discharge capacity of Na0.67Cu0.2Mg0.1Fe0.2Mn0.5O2 is as high as 212.0 mAh g-1 at 0.1C rate and 186.2 mAh g-1 at 0.2C rate. After 80 cycles, the capacity can still maintain 88.1%. Moreover, the capacity and cycle performance as well as the stability can still remain stable even in the high-voltage window. Therefore, this work offers an insightful exploration for the development of composite cathode materials for SIBs.

Programming memristor arrays with arbitrarily high precision for analog computing.

In-memory computing represents an effective method for modeling complex physical systems that are typically challenging for conventional computing architectures but has been hindered by issues such as reading noise and writing variability that restrict scalability, accuracy, and precision in high-performance computations. We propose and demonstrate a circuit architecture and programming protocol that converts the analog computing result to digital at the last step and enables low-precision analog devices to perform high-precision computing. We use a weighted sum of multiple devices to represent one number, in which subsequently programmed devices are used to compensate for preceding programming errors. With a memristor system-on-chip, we experimentally demonstrate high-precision solutions for multiple scientific computing tasks while maintaining a substantial power efficiency advantage over conventional digital approaches.

Hardware implementation of memristor-based artificial neural networks.

Artificial Intelligence (AI) is currently experiencing a bloom driven by deep learning (DL) techniques, which rely on networks of connected simple computing units operating in parallel. The low communication bandwidth between memory and processing units in conventional von Neumann machines does not support the requirements of emerging applications that rely extensively on large sets of data. More recent computing paradigms, such as high parallelization and near-memory computing, help alleviate the data communication bottleneck to some extent, but paradigm- shifting concepts are required. Memristors, a novel beyond-complementary metal-oxide-semiconductor (CMOS) technology, are a promising choice for memory devices due to their unique intrinsic device-level properties, enabling both storing and computing with a small, massively-parallel footprint at low power. Theoretically, this directly translates to a major boost in energy efficiency and computational throughput, but various practical challenges remain. In this work we review the latest efforts for achieving hardware-based memristive artificial neural networks (ANNs), describing with detail the working principia of each block and the different design alternatives with their own advantages and disadvantages, as well as the tools required for accurate estimation of performance metrics. Ultimately, we aim to provide a comprehensive protocol of the materials and methods involved in memristive neural networks to those aiming to start working in this field and the experts looking for a holistic approach.

Trans-olecranon fracture posterior dislocation: a novel type of elbow injury.

BACKGROUND: Based on our experiences, we found that a kind of elbow injury is characterized by an olecranon fracture accompanied by elbow joint posterior dislocation with the proximal radioulnar joint intact. The aim of this study was to better define this kind of severe elbow instability, which has not been previously reported. METHODS: We retrospectively analyzed all patients with olecranon fractures who were treated at our institution from January 2013 to April 2021. Data on these patient demographics, injury characteristics, preoperative and postoperative imaging, surgical management, and outcomes were recorded and analyzed. We also made the inclusion criteria and exclusion criteria. RESULTS: A total of 309 patients were diagnosed olecranon fractures in our institution, and ten patients met the inclusion criteria, 9 males and 1 female, with an average age of 40.6 ± 12.7 years (26-68 years). Eight patients (80%) were comminuted, and two were oblique olecranon fracture. Nine patients (90%) suffered coronoid process fractures, eight fractures were type III, and one was type II. Eight patients (80%) suffered radial head fractures, seven fractures were type II, and one was type III. All patients suffered lateral collateral ligament complex injury. All patients underwent surgical management and were followed up on average for 15.8 ± 3.2 months (12-20 months). The motion of the elbow and functional outcome were evaluated with several methods. The mean arc of the elbow movement was 131.6° ± 6.0° (124°-140°), and the mean arc of the forearm rotation was 158.5° ± 17.8° (128°-180°). Nine patients' functional results according to the Mayo Elbow Performance Score (MEPS) were excellent with a mean score of 96.5 ± 5.3 points (85-100 points), and another was good. The mean score according to the Broberg and Morrey functional rating index was 98.8 ± 2.5 points (92-100 points), nine patients were excellent, and another was good. The mean Disabilities of the Arm, Shoulder, and Hand (DASH) score was 0.75 ± 1.2 points (0-3.3 points). CONCLUSIONS: Trans-olecranon fracture posterior dislocation is a rare injury and has unique characteristics, and it is a kind of complex elbow instability involving the coronoid process and radial head fractures. After bony structure is restored, the repairment of lateral collateral ligament complex is also important to the stability of the elbow joint. Correct understanding of this kind of injury and reasonable treatment plan can achieve good function.

Three-dimensional printing versus traditional surgery for inveterate pelvic and acetabular fractures: A retrospective study of 37 patients.

Treatment of deformed pelvic and acetabular fractures is a considerable challenge for orthopedic surgeons. The aim of this study was to assess the availability of a three-dimensional (3D) printing model used in patients with inveterate pelvic and acetabular fractures by comparing 3D printing technology with conventional surgery. We conducted a retrospective review of patients with inveterate pelvic and acetabular fractures treated in our department between January 2008 and June 2020. The patients were divided into 2 groups according to their willingness. Perioperative data and clinical outcomes were compared to evaluate clinical efficacy. The t-test, Fisher exact test, and multivariable logistic regression analysis were conducted. A P value of .05 or less was considered to be statistically significant (two-tailed). Thirty-seven patients were enrolled in our study. Seventeen patients were divided into the case group treated by 3D printing model-assisted preoperative planning, and 20 patients were divided into the control group treated by conventional surgery. Patients treated with the 3D printing model had significantly shorter operation times, less blood loss, and shorter fluoroscopy times. Patients in the case group also showed better pain relief according to visual analog scale scores. However, the elevations in pelvis and hip joint functional outcomes were similar between the 2 groups, and no significant difference was shown in the radiological result. The usage of 3D printing techniques in patients with inveterate pelvic and acetabular fractures is of great importance in preoperative preparation and optimization of surgery but cannot improve postoperative function compared with conventional treatment.

Management and Outcome of Elderly Patients With Patellar Fracture Treated With Novel Modified Cerclage Wiring.

Introduction: The purpose of this study is to assess the efficacy and security of a fixation method for fixing patellar fractures in elderly patients utilizing modified cerclage wire. Methods: From January 2015 to December 2020, 31 cases (age≥65 years old) of closed patellar fracture were treated by modified cerclage wiring. Patients in these instances ranged in age from 65 to 87 (73.7 ± 7.2 years), with 15 men and 16 women. 4 instances were type 34-C1 (transverse fracture) according to the AO/OTA classification, 27 cases (87%) were comminuted fractures, including 11 cases that were type 34-C2 (3 fragments), and 16 cases that were type 34-C3 (more than 3 fragments). Postoperative problems such as fragment re-displacement, nonunion, internal fixation loosening, infection, and internal fixation rupture were evaluated. The clinical grading systems of Böstman were used to assess the postoperative clinical outcomes. Results: Thirty one patients in all were monitored for 14 to 31 months (22.2 ± 4.5 months). After the procedure, the fracture took 2.5-3.5 months (2.92 ± .25 months) to heal. There were no postoperative issues like infection, dislocation, implant breakage, uncomfortable hardware, or post-traumatic osteoarthritis. According to the clinical grading scales of Böstman, the average score of the final follow-up was 28.6 ± 1.1 (range 26-30). 29 (94%) of the patients had excellent results, whereas just 2 (6%) had good results. The patient's knee flexion activity ranged from 110 to 140°, making for a favorable prognosis. Conclusion: Most patella fractures in the elderly are comminuted. Elderly patients with patellar fractures may be successfully treated with modified cerclage wire, with good results and no noticeable side effects.