Lateral Impact Research Articles

Experimental Investigation on the Response of Elliptical CFT Columns Subjected to Lateral Impact Loading

This study reports an experimental investigation on the impact behavior of elliptical concrete-filled steel tubular (CFT) columns subjected to lateral loading. A total of five CFT columns, including one circular cross-section and four elliptical cross-sections, were tested using a horizontal-impact-testing system. The influences of the impact velocity, the impact times, and the cross-section geometry on the dynamic response of the elliptical CFT columns were analyzed. The experimental results have shown that the specimens withstood the global displacements without the buckling of the steel tubes. The strain rates of the steel tubes in this paper were small. The impact velocity had significant influences on the impact load-time histories and energy absorption. Meanwhile, the impact times had little influence on the impact force and displacement at the same impact velocity. Circular CFT columns have the highest ductility and impact-energy-absorption capacity. Based on the finite element analysis software ABAQUS, the finite element models of the elliptical CFT columns under impact loads were established. The simulation results were in good agreement with the experimental results. Finally, the mechanical mechanism of the elliptical CFT columns under lateral impact was analyzed by the finite element model.

Effect of glenosphere lateralization with and without coracoacromial ligament transection on acromial and scapular spine strain in reverse shoulder arthroplasty.

Small changes in deltoid tension and moment arm due to glenosphere lateralization may be associated with an increase in acromion or scapular spine strain in reverse shoulder arthroplasty (RSA), which can lead to stress fracture. The coracoacromial ligament (CAL) may be protective and lower the strain seen on the acromion or scapular spine. This biomechanical study investigated the impact of glenosphere lateralization and CAL integrity on acromion and scapular spine strain after RSA. Ten cadaveric specimens were tested on a custom dynamic shoulder frame. Acromial and scapular spine strain were measured at 0°, 30°, and 60° of abduction using strain rosettes fixed to the acromion (Levy Type 2) and the scapular spine (Levy Type 3). Specimens were first tested with a standard commercially available RSA implant with zero lateralization and then subsequently with the+3 and+6 lateralizing glenospheres for that implant. The CAL was then cut in each specimen and testing was repeated with the 0,+3, and+6 glenospheres. Maximal strain was recorded at both the acromion and scapular spine and analysis of variance compared strain across various abduction angles and glenospheres with and without CAL transection. In the intact CAL group, maximal strain decreased significantly at the acromion with abduction from 0° to 30° and 0° to 60°, however, at the scapular spine abduction did not significantly impact strain. Maximal strain decreased significantly with increasing abduction from 0 to 30 and 0 to 60 at both the acromion and scapular spine in the cut CAL group. Average strain at the acromion was significantly higher in the cut group (844.7 με) versus the intact group (580.3 με), a difference of 31.3% (P=.0493). Average strain at the scapular spine, did not differ in the cut group (725 με) compared with the intact group (787 με) (P=.3666). There were no statistically significant differences in acromial or scapular spine strain between various levels of glenosphere lateralization in either the cut or intact state. In this biomechanical study, arm abduction decreased acromial and scapular spine strain following RSA. Cutting the CAL significantly increased strain at the acromion, and did not significantly alter strain at the scapular spine for all angles of abduction, differing from prior literature. Glenosphere lateralization did not have a significant effect on strain at the levels studied regardless of CAL status. Continued study of the complexion relationship between surgical and implant factors on strain following RSA is needed.

Quantifying the role of openings in the impact of a dam-break-induced flood on a porous building

It becomes necessary to identify the role of openings in the impact of floods on porous buildings to better set up effective strategies for people security within buildings and implement engineering measures for building safety. In this study, a 3D numerical model is applied to identify the role of openings in the impact of a dam-break-induced flood on a porous building under different opening configurations, including different porosities of the front and back walls, various porosities of the back wall and various positions and sizes of the side window. (i) An increasing size of the front and back doors leads to a reduced maximum water level upstream of the building and a reduced area of the wake zone behind the back wall; the maximum longitudinal impact force significantly decays with the porosity in terms of a quadratic function form. (ii) A variation in the size of the back door plays a role in controlling the outflow discharge of floodwater from the building; however, it yields no clear difference in the resultant longitudinal impact force. (iii) In the short-term, the presence of the side window plays no clear role in affecting the flow field around the building; however, in the moderate timeframe, there is a clear lateral exchange: the positions of the side windows play a clear role, whereas the size of the lower side window seems to be less important; the existence of the side window greatly decreases the lateral impact force, especially for the lower sidewall. These results are of value to better understand the physical mechanism of the impact process on a porous building for implementing tailored measures for people security and structural safety.

Treatment with vascular endothelial growth factor-A worsens cognitive recovery in a rat model of mild traumatic brain injury.

Mild traumatic brain injury (mTBI) is a common and unmet clinical issue, with limited treatments available to improve recovery. The cerebrovascular system is vital to provide oxygen and nutrition to the brain, and a growing body of research indicates that cerebrovascular injury contributes to mTBI symptomatology. Vascular endothelial growth factor-A (VEGF-A) is a potent promoter of angiogenesis and an important modulator of vascular health. While indirect evidence suggests that increased bioavailability of VEGF-A may be beneficial after mTBI, the direct therapeutic effects of VEGF-A in this context remains unknown. This study therefore aimed to determine whether intracerebroventricular administration of recombinant VEGF-A could improve recovery from mTBI in a rat model. Male and female Sprague-Dawley rats were assigned to four groups: sham + vehicle (VEH), sham + VEGF-A, mTBI + VEH, mTBI + VEGF-A. The mTBI was induced using the lateral impact model, and treatment began at the time of the injury and continued until the end of the study. Rats underwent behavioral testing between days 1 and 10 post-injury, and were euthanized on day 11 for post-mortem analysis. In males, the mTBI + VEGF-A group had significantly worse cognitive recovery in the water maze than all other groups. In females, the VEGF treatment worsened cognitive performance in the water maze regardless of mTBI or sham injury. Analysis of hippocampal tissue found that these cognitive deficits occurred in the presence of gene expression changes related to neuroinflammation and hypoxia in both male and female rats. These findings indicate that the VEGF-A treatment paradigm tested in this study failed to improve mTBI outcomes in either male or female rats.

Dynamic behavior of UHPC member under lateral low-velocity impact: Mesoscale analysis

Ultra-High Performance Concrete (UHPC), which mainly consists of the cementitious matrix and incorporated fibers, has superior impact-resistance compared with the normal strength concrete. Concerning the impact-resistant evaluation and performance-based design of UHPC structure under lateral low-velocity impact, a mesoscale modeling analysis approach considering the bond-slip behavior between random distributed fibers and cementitious matrix of UHPC is proposed. Firstly, the Continuous Surface Cap (CSC) model parameters for the matrix of UHPC were calibrated, and validated through a series of fundamental mechanical tests and low-velocity impact test. Secondly, by conducting a single steel fiber pull-out test, the fiber-matrix interaction was examined, and an appropriate interaction algorithm considering bond-slip effect was employed in the commercial program LS-DYNA. Then, the mesoscale model of UHPC was established through a self-coding program in MATLAB. The reliability of the mesoscale model and analysis approach were systematically verified at both material level (uniaxial compression, uniaxial tension, three- and four-point bending tests) and member level (total 15 low-velocity impact scenarios considering various member types, sectional shapes, sectional dimensions, and compressive strength). Finally, the influence of fiber volume fraction on the dynamic behavior of UHPC member was examined. It derives that the incorporated fibers can help reduce the lateral deflections and avoid the brittle punching-shear failure mode of UHPC members, and the optimal fiber volume fraction of 1.5% for the impact-resistant design is recommended. The present work provides a new way to accurately and conveniently evaluate the low-velocity impact-resistance and predict the dynamic behavior of the arbitrary configured UHPC structure.

Dynamic behavior of RC columns confined with CFRP grid-reinforced ECC subjected to lateral low-velocity impact

To verify its feasibility of carbon fiber reinforced polymer (CFRP) grid-reinforced engineered cementitious composites (ECC) on improving the impact resistance of reinforced concrete (RC) column, impact tests on cantilever RC column and RC column confined with CFRP grid-reinforced ECC were carried out. Detailed finite element model of the laboratory tests was established, a numerical material model of concrete named continuous surface cap model (CSCM) was employed to simulate dynamic behavior of ECC. Parametric studies were carried out to investigate the effect of ECC and CFRP on the dynamic behavior of CFRP grid-reinforced ECC confined columns. Test results showed that CFRP grid-reinforced ECC had a significant effect in limiting the development of shear cracks and improving the shear capacity of RC column. Numerical results indicated that the impact force, displacement and failure mode of CFRP grid-reinforced ECC confined column could be well predicted by the finite element model. Parametric analysis results demonstrated that under horizontal impact loading, ECC confined columns were prone to shear failure, while CFRP grid-reinforced ECC confined columns were more susceptible to overall failure at the column footings. Meanwhile, the effect of CFRP grid and ECC on the impact force and displacement of confined column was also discussed.

Experimental and numerical study of the performance of geopolymer concrete columns reinforced with BFRP bars subjected to lateral impact loading

Structural columns during their service life may be subjected to lateral impact load. It is therefore imperative to investigate the impact-resistant performance of columns for structural safety. Using geopolymer concrete (GPC) and basalt fibre reinforced polymer (BFRP) bars leads to sustainable and corrosion-resistant durable structures, therefore has great application potential in construction. In the present study, GPC columns reinforced with BFRP bars and steel bars were cast and tested under pendulum impact while their ordinary Portland cement concrete (OPC) counterparts were also prepared and tested for comparison. In addition, a numerical model was developed in LS-DYNA and calibrated against the test results. The test and numerical results showed that concrete columns reinforced with BFRP bars experienced severer damage than those reinforced with steel bars under low impact velocity (e.g. 0–2.71 m/s) due to the lower elastic modulus of BFRP bars. However, under relatively high impact velocity (e.g. 3.15–4.43 m/s), concrete columns reinforced with BFRP bars showed superior impact resistance than those reinforced with steel bars due to the much higher tensile strength of BFRP bars, indicating BFRP bars have potential as an alternative to steel bars for reinforcement to resist large impact loads. Additionally, GPC columns showed similar or even better impact resistance than OPC columns under impact loading, indicating GPC could be a good alternative to OPC in construction of structural columns.

Design Calculation for Concrete-Filled Steel Tube under Soft Lateral Impact

In recent decades, the rapid development of transportation construction has increased the possibility of concrete-filled steel tubes (CFSTs) subjected to soft lateral impact. Some kinds of deviation may still exist between the soft impact process and its design prediction due to frequent safety accidents. To improve the prediction accuracy, this paper contrasted the current soft impact design with the experimental impact processes of CFSTs. The current design is represented by the method and route in Eurocode-1 Actions on structures, which belongs to the one-step type. Extra parameters were added to the one-step method to describe the inertia effect of CFST. According to the experiments and predictions, the soft impact process contains two stages, which are the initial peak stage (IPS) and the stable stage (SS). The current one-step method is consistent with SS but incorrect in IPS and its accuracy is related to the proportion of IPS and SS. An empirical formula, based on the weight of IPS, is summarized to evaluate the overall error of the one-step method in the soft impact design of CFST. This error is due to the unreasonable assumption of the inertial effect in IPS. For the demands of an accurate design in IPS, a new technical route is proposed, consisting of two steps: qualitative analysis and two-stage calculation. The qualitative analysis achieved an approximate quantitative division of IPS and SS, and provided the design loads for the two-stage calculation. The two-stage calculation supplemented the prediction of the inertia effect in IPS and independently estimated the resistances and responses of CFST in the two stages. The above qualitative analysis and two-stage calculation constituted the two-step method and its accuracy and applicability are generally better than that of the one-step design.

Experiment and numerical simulation of thin-walled cylindrical containers subjected to lateral impact

The dynamic performance of vertical cylindrical storage tanks under lateral impact of explosive fragments is important for its safe loading. In this paper, the method of combining experiments and numerical simulation is employed. Based on the simplified scaled model of thin-walled cylindrical containers, the lateral impact model experiments are carried out by using the drop hammer impact tester. Typical deformations and failure modes of the structure are then obtained. After processing the experimental data to obtain the load-deformation curve and the absorption energy curve, the curves are analyzed to study the dynamical response characteristics for cylindrical containers under impact as well as the influences for container length and impact velocity on the structural dynamical response. Then, the LS-DYNA program is applied for simulating the impact procedure and its dynamic response. With the reliability of the numerical model being verified, the stress distribution of the cylindrical container during the impact process is analyzed. Through finite element parametric analyses, combined with experimental results, the influences of impact velocity, length-to-radius ratio and radius-to-thickness ratio on dynamical responses as well as failure modes of the structure are investigated. It is shown that the failure mode of the cylindrical container changes with impact velocity and radius-to-thickness ratio, but is not affected by length-to-radius ratio. The variation of peak deformation and average force of the structure with parameters such as impact velocity are obtained.

Lateral impact noise II: Practice and recommended procedures

Impact noise insulation has traditionally been thought of mostly in terms of vertical adjacencies, and ASTM E1007 provides no guidance for performing such a measurement in a lateral, diagonal, or other non-vertical condition. Because lateral impact transmission can be significant, the authors have developed methods and practices for performing this measurement (see papers by the authors at ICSV 2017 and Inter-Noise 2019). ISO 16283-2 also describes procedures and methods for the measurements and analysis of lateral impact noise measurements. The various measurement methods are compared and evaluated. For some assembly types, there is an advantage to maintain a constant distance from tapping machine to the separating partition. Appropriate ratings for categorization of lateral impact isolation are discussed, and changes to E1007 to clarify the measurement method are proposed.

Lateral impact noise I: Theory and application

Impact noise insulation has traditionally been thought of mostly in terms of vertical adjacencies. However, impact noise is transmitted in all directions though a building, and lateral and diagonally adjacent impact noise transmission can be significant. Lateral and diagonal impact transmission is a one-junction structural flanking path and is, therefore, amenable to statistical energy analysis-based calculation methods such as ISO 12354. In this paper, we review the relevant results from structural flanking path calculations and show how this provides a framework for understanding major features of lateral impact noise transmission such as the frequency dependence and effect of structure type. In turn, measurement of lateral impact noise provides a method of estimating the vibration reduction across junctions. These findings are illustrated with examples from field testing.

Spinal Cord Boundary Conditions Affect Brain Tissue Strains in Impact Simulations.

Brain and spinal cord injuries have devastating consequences on quality of life but are challenging to assess experimentally due to the traumatic nature of such injuries. Finite element human body models (HBM) have been developed to investigate injury but are limited by a lack of biofidelic spinal cord implementation. In many HBM, brain models terminate with a fixed boundary condition at the brain stem. The goals of this study were to implement a comprehensive representation of the spinal cord into a contemporary head and neck HBM, and quantify the effect of the spinal cord on brain deformation during simulated impacts. Spinal cord tissue geometries were developed, based on 3D medical imaging and literature data, meshed, and implemented into the GHBMC 50th percentile male model. The model was evaluated in frontal, lateral, rear, and oblique impact conditions, and the resulting maximum principal strains in the brain tissue were compared, with and without the spinal cord. A new cumulative strain curve metric was proposed to quantify brain strain distribution. Presence of the spinal cord increased brain tissue strains in all simulated cases, owing to a more compliant boundary condition, highlighting the importance of the spinal cord to assess brain response during impact.

Lateral Impact Response of Rubberized-Fibrous Concrete-Filled Steel Tubular Columns: Experiment and Numerical Study

This paper presents an experimental and numerical study on the lateral impact behavior of rubberized-fibrous concrete-filled steel tubular (CFST) columns. Four types of concrete were utilized in the experimental program in the infilled columns: normal concrete (NC), rubberized concrete (RuC), steel fiber concrete (SFC), and hybrid RuC-SFC. Twelve specimens were tested using drop-weight impact with fixed-sliding boundary conditions. Three different transverse impact energies were produced by applying two masses of the hammers dropped from two different heights. A high-speed camera was implemented to measure the mid-span deflection against time. A 3-D finite element model was presented and verified against the tested specimens and some other experimental work from the literature. Load-displacement curves, the impact force time history, impact energy absorption, and failure modes of the CFST columns under the lateral impact were fully analyzed. The present results showed that at, certain impact energies, the steel tubular suffered only from the plastic deformation, beyond which it started cracking depending on the type of filled concrete. The steel tubular filled with hybrid RuC-SFC showed the highest resistance to crack formation, followed by that filled with SFC, while those filled with NC showed the lowest resistance to crack formation. There is an agreement between the numerical and the experimental results.

The Incidence of Posterolateral Tibial Plateau and Central Lateral Femoral Condylar Impaction Fractures in a Pediatric and Young Adult Population.

Posterolateral tibial plateau and central lateral femoral condylar impaction fractures are known to occur in the setting of anterior cruciate ligament (ACL) tears. There have been no prior investigations into the incidence and morphology of posterolateral tibial plateau impaction fractures in the setting of ACL injury in a pediatric population. Patients between 9 and 22 years of age with knee magnetic resonance imagings (MRIs) performed demonstrating complete or partial ACL tear were included in this study. MRI reports were reviewed to denote the presence of posterior cruciate ligament, medial collateral ligament, or lateral collateral ligament injury, meniscus tears, cartilage lesions. MRIs were reviewed by 2 fellowship-trained orthopaedic surgeons to denote the presence of posterolateral tibial plateau and central lateral femoral condylar impaction fractures and physeal status of femoral and tibial physes. Statistical analysis performed included χ 2 analysis and the Student t testing. A total of 328 patients with a primary ACL tear were identified. The mean age of patients included was 16.5 years (range: 9.0-21.5). The incidence of posterolateral tibial plateau impaction fractures was 83/328 (25.3%) while the incidence of lateral femoral condylar impaction fractures was 119/328 (36.3%). Bipolar impaction fractures occurred in 37/328 (11.3%). Of the 83 tibial impaction fractures identified, 82 were low-grade morphologic subtypes. Patients with lateral tibial plateau impaction fractures were older than those with no fracture (17.2±2.2 vs. 16.3±2.1, P =0.001). Only 3/38 (7.9%) patients with an open tibial physis sustained a tibial plateau impaction fracture compared with 80/290 (27.6%) with a closed tibial physis (χ 2 value: 6.9, P =0.009). There was no difference in proportion of patients with lateral femoral condylar impaction fractures based on femoral physeal status ( P =0.484). The incidence of posterolateral tibial plateau impaction fractures in the setting of ACL tear in a pediatric and young adult patient population appears to be lower while lateral femoral condylar impaction fractures occur more frequently when comparing to previously reported incidences found in adult populations in the literature. Furthermore, posterolateral tibial plateau impaction fractures occur less frequently in those with an open proximal tibial physis and high-grade posterolateral tibial plateau bone loss is exceedingly rare in pediatric and young adult patients. Lateral femoral condylar impaction fractures are associated with lateral meniscal tears and medial meniscal ramp lesions. Level IV-cross-sectional study.

Simulating Prophylactic Fixation Methods for Osteoporotic Femoral Neck Fracture Prevention.

Geriatric patients who suffer femoral neck fractures have high morbidity and mortality. Prophylactic fixation of the femoral neck is a potential avenue to reduce the incidence of femoral neck fractures. We studied 3 different implants traditionally used to stabilize the femoral neck: 6.5mm cannulated screws (CANN), the femoral neck system (FNS) (Depuy Synthes), and the dynamic hip screw (DHS) (Depuy Synthes). Five osteoporotic Sawbone femurs were used for each model and a control group. Two scenarios were investigated: single leg stance to measure construct stiffness and lateral impact to measure construct stiffness, energy to fracture, and qualitative examination of fracture patterns. Stiffness for each femur and energy to fracture for the lateral impact scenario were calculated and compared between groups using one-way ANOVA. DHS showed significantly higher stiffness than the other 2 implants and the control in single leg stance. In the lateral impact scenario, the DHS and CANN were significantly stiffer FNS and the control. Femurs implanted with CANN tended to fracture at the greater trochanter while FNS fractured in a transverse subtrochanteric pattern, and DHS fractured obliquely in the subtrochanteric region. FNS and DHS experienced fracture patterns less amenable to surgical correction. CANN and DHS proved better able to resist external forces in the lateral fall scenario. CANN also proved better able to resist external forces in the single leg stance scenario and experienced a more amenable fracture pattern in the lateral fall scenario. FNS was less able to resist external forces compared with the other implants. This work informs the potential implications between the choice of implants that, although historically have not been used prophylactically, may be considered in the future for prophylactic stabilization of the femoral neck. Cadaveric study and clinical trials are recommended for further study.

A Stability Training Method of Legged Robots Based on Training Platforms and Reinforcement Learning with Its Simulation and Experiment.

This paper continues the proposed idea of stability training for legged robots with any number of legs and any size on a motion platform and introduces the concept of a learning-based controller, the global self-stabilizer, to obtain a self-stabilization capability in robots. The overall structure of the global self-stabilizer is divided into three modules: action selection, adjustment calculation and joint motion mapping, with corresponding learning algorithms proposed for each module. Taking the human-sized biped robot, GoRoBoT-II, as an example, simulations and experiments in three kinds of motions were performed to validate the feasibility of the proposed idea. A well-designed training platform was used to perform composite random amplitude-limited disturbances, such as the sagittal and lateral tilt perturbations (±25°) and impact perturbations (0.47 times the robot gravity). The results show that the proposed global self-stabilizer converges after training and can dynamically combine actions according to the system state. Compared with the controllers used to generate the training data, the trained global self-stabilizer increases the success rate of stability verification simulations and experiments by more than 20% and 15%, respectively.

GFRP bar RC columns under lateral low-velocity impact: an experimental investigation

The performance of GFRP (Glass Fiber polymer) bar RC (Reinforced Concrete) circular columns subjected to lateral impact was experimentally investigated. Sixteen GFRP bar RC column specimens representing offshore bridges were constructed and tested. Laboratory tests were performed considering two types of loading conditions (static monotonic and lateral impact) and two different boundary conditions (cantilever and propped cantilever). For the static tests, the displacement and loading performances were estimated by applying lateral monotonic static load through a hydraulic actuator. For the dynamic impact tests, a steel-made truck with a rigid nose was used to simulate the typical vehicle or vessel collision scenarios. The dynamic lateral impact and displacement responses were detailed evaluated under three different impact velocities (2.25, 3.00, and 4.50 m/s). Moreover, a semi-empirical model based on experimental results was proposed for a performance displacement-based structural assessment and maximum displacement prediction. It is found that GFRP bar RC columns have similar performance compared to traditional steel RC columns under lateral impact loads given the same static capacity.

Three-Dimensional Finite Element Analysis on Mandibular Biomechanics Simulation under Normal and Traumatic Conditions

The main objective was to examine the biomechanical behavior of the mandible under standardized trauma and to develop models of biomechanical responses when the mandible is subjected to various simulated impacts. A homogenous model based on the bone’s average mechanical properties was used. To simulate external loads on the mandible, forces on the chin, forces in an anteroposterior direction, and forces from the basilar edge were applied. To simulate mandibular biomechanics, we employed a model created in the ANSYS v19.0 software. The skull with the temporomandibular joint (TMJ) from the Grabcad website was used as the geometric mandibular model. We attempted to simulate the stresses developed in the mandible by impact forces. The amount of force (F) corresponded to the fall of a five-kilogram body (the head), from a height of two meters (F = 6666.7 N). The impact force was applied perpendicular to an arbitrary surface of an area of 10−3 m2. Impact on the chin region and lateral impact on the mandible, from the basilar edge to the gonion were examined. The investigated clinical situations were mandibular complete dentition; jaw with missing mandibular molars; missing third molar and first and second premolars; missing canine, third molar, first and second premolars, and complete edentation. In a normal bite, the highest stress was on the TMJ area. In case of impact on the chin, in complete edentation, a mandibular fracture occurred; in case of impact on the gonion, all stress values exceed the limit value above which the mandible in the condyle area may fracture.

Impact and post-impact behaviours of steel-reinforced concrete-filled steel tubular columns after exposure to fire

This paper presents a numerical investigation on the lateral impact and post-impact behaviours of steel-reinforced concrete-filled steel tubular (SRCFST) columns after exposure to fire. The finite element analysis (FEA) model of post-fire SRCFST columns under lateral impact is developed by the ABAQUS software and calibrated. The impact responses of post-fire columns are analyzed, namely the impact process, the development of internal force, the energy change and plastic damage, etc. The impact resistance of SRCFST and CFST columns after fire is further compared, and the residual capacity of post-fire columns after lateral impact is studied. The results show that the SRCFST column after fire exhibits excellent impact performance, and the influence of fire degree on the impact resistance degradation of SRCFST columns is significantly smaller than that of CFST columns. A parametric study is also carried out to analyze the influence of various parameters on impact responses of post-fire SRCFST columns, and simplified methods are finally proposed to evaluate the impact resistance and residual capacity of post-fire SRCFST columns under lateral impact.

Epidemiology of pelvic and acetabular fractures across 12-mo at a level-1 trauma centre.

BACKGROUNDDespite motor-vehicle safety advancements and increasingly rigorous workplace safety regulations, trauma/suicide remains the leading cause of death under the age of 45 in the United Kingdom. To promote centralisation of care and optimisation of major trauma outcomes, in 2012 the National Health Service introduced the Trauma Network System. To our knowledge, this is the first study to analyse the epidemiology of pelvic and acetabular trauma over a one-year period at a level-1 trauma centre in the United Kingdom, since nationwide introduction of the Trauma Network System.AIMTo characterize the epidemiology of high-energy pelvic and acetabular fractures over a one-year period at a level-1 trauma centre, and explore both resources required to care for these patients and opportunities for future research and injury prevention initiatives.METHODS227 consecutive patients at a level-1 trauma centre with pelvic and acetabular fractures were analysed between December 2017-December 2018. Paediatric patients (< 18 years) and fragility fractures were excluded, leaving 175 patients for inclusion in the study. Statistical analysis was performed using Fisher’s exact test for categorical variables.RESULTS72% of pelvic and acetabular fractures occurred in male patients at a median age of 45 years. 15% were the result of a suicide attempt. 48% of patients required pelvic or acetabular surgery, with 38% undergoing further surgery for additional orthopaedic injuries. 43% of patients were admitted to intensive care. The median inpatient stay was 13 days, and the 30- day mortality was 5%. Pelvic ring trauma was more commonly associated with abdominal injury (P = 0.01) and spine fractures (P < 0.001) than acetabular fractures. Vertical shear pelvic ring fractures were associated with falls (P = 0.03) while lateral compression fractures were associated with road traffic accidents (P = 0.01).CONCLUSIONHigh energy pelvic and acetabular fractures are associated with concomitant orthopaedic fractures (most commonly spine and lower limb), intensive care admission and prolonged inpatient stays. Most pelvic ring injuries secondary to road traffic accidents are lateral compression type, demonstrating the need for future research to drive advancements in lateral impact vehicle safety along with mental health surveillance for those deemed to be potential suicide risks.