Climate change poses a significant threat to public health. Existing studies on the health impacts of climate change focus primarily on chronic and infectious diseases, with limited research on injury. To address this gap, this issue launched a special column titled "Climate change and injuries". Through interdisciplinary integration of atmospheric science and public health, we explored the impact of climate change on injury risk and burden from diverse perspectives. This initiative aims to deepen a comprehensive understanding of the impact of climate change on human health, enhance China's capacity to address climate-related health risks, reduce associated disease burden, and provide scientific evidence for targeted adaptation measures.

Background Previous studies found that high temperature and heatwave increase the risk of traffic injuries. The complex road conditions in Yunnan Province result in frequent traffic accidents. However, there is limited evidence on the correlation between heatwave and traffic injuries in Yunnan Province. Objective To assess the association between heatwave events and traffic injuries, to estimate its disease burden, and to identify relevant sensitive groups. Methods We collected data on traffic injury cases and concurrent meteorological information from four surveillance sites in Yunnan Province, China: Dali, Lufeng, Zhaoyang, and Qilin from May to September each year from 2015 to 2023. Traffic injury cases refer to patients who visited the outpatient or emergency departments of local surveillance hospitals for the first time due to traffic injuries. Meteorological data were derived from the fifth generation atmosphericreanalysis dataset of the global climate provided by the European Centre for Medium-Range Weather Forecasts. A time-stratified case-crossover design combined with distributed lag non-linear model was used to analyze the association between short-term exposure to heatwave and traffic injuries. We also conducted subgroup analyses by sex, age, occupation, injury cause, activity at the time of injury occurrence, and severity of injury. Results A total of 34764 traffic injury surveillance cases were included in the analysis. The risk of traffic injuries occurred during heatwave was 1.13 times (95%CI: 1.07, 1.20) greater than those occurred during non-heatwave, and 2.64% (95%CI: 1.49%, 3.73%) of traffic injuries were attributed to heatwave exposure throughout the study period. The results of stratified analysis showed greater impacts of heatwave on the risk of traffic injuries in female [odds ratio (OR)=1.17, attributable fraction (AF)=3.23%], people aged 15-64 years (OR=1.13, AF=2.68%), farmers/workers (OR=1.22, AF=4.07%), people with non-motor vehicle traffic injuries (OR=1.17, AF=3.24%), people who were driving or riding when injuries occurred (OR=1.12, AF=2.43%), and people with minor injuries (OR=1.18, AF=3.49%) ( P<0.05). Longer duration [excess risk (ER)=0.99%] and greater intensity (ER=4.12%) of heatwave had greater impacts on the risk of traffic injuries (P<0.05). Conclusion Heatwave events are associated with an increased risk of traffic injuries. Female, people aged 15-64, farmers/workers, people with non-motor vehicle traffic injuries, those injured while driving/riding a vehicle, and people with minor injuries are particularly vulnerable. The findings suggest that targeted mitigation and adaptation measures should be taken to address the risk of traffic injuries associated with extreme climate events.

Background Injury poses a serious threat to human health. As global warming continues to intensify, there is an urgent need to explore the impact of temperature changes on injury deaths. However limited research has focused on this issue. Objective To investigate the relationship between daily mean temperature change (Tm) and injury death, as well as to estimate the associated future death burden in Hunan Province. Methods We employed an individual-level, time-stratified case-crossing design to establish a conditional logistic regression model to analyze the exposure-response relationship between daily mean temperature change and injury death in Hunan Province from 2013 to 2018. Consequently, we conducted subgroup analysis of gender, age group, and injury type. Finally, we estimated the excess burden of injury death attributable to temperature changes under a sustainable development path [low emission scenario (SSP1-2.6)], regional competition path [high emission scenario (SSP3-7.0)], or fossil fuel development path [very high emission scenario (SSP5-8.5)]. Results The study collected 155577 injury deaths in Hunan Province. The results indicated that for each 1 ℃ increment in daily mean temperature, the cumulative excess risk (CER) of injury mortality among Hunan residents increased by 0.71% (95%CI: 0.53%, 0.90%). Notably, the CER for intentional injuries (1.06%, 95%CI: 0.51%, 1.61%) was higher than that for unintentional injuries (0.66%, 95%CI: 0.46%, 0.87%). Warmer temperatures were positively associated with CER of mortality due to drowning, falls, transport injuries, assaults, and suicides, while they were negatively associated with mortality due to poisoning. Compared with 2010–2019, for 2090–2099, the excess mortality rate (EMR) due to ambient temperature increase in Hunan Province under the SSP5-8.5 scenario (14.62/100000, 95%CI: 10.81/100000, 18.40/100000) would be higher than that of the SSP3-7.0 scenario (10.28/100000, 95%CI: 7.58/100000, 12.97/100000) and the SSP1-2.6 scenario (3.35/100000, 95%CI: 2.46/100000, 4.23/100000); the EMR would be around 2.5 times among men (20.64/100000, 95%CI: 14.44/100000, 26.8/100000) than that among women (8.33/100000, 95%CI: 3.98/100000, 12.6/100000). Among unintentional injuries, the leading contributors to EMR would be drowning (4.46/100000), falls (3.96/100000), and transport injuries (2.96/100000). And among intentional injuries, the EMR for suicide (2.08/100000) would be higher than that for assault (0.47/100000). Conclusion Climate warming will increase the total burden of injury-related deaths among residents in Hunan Province, especially in the absence of effective mitigation strategies and measures. It is necessary to strengthen the prevention and control of severe injuries closely related to temperature changes, such as drowning, falls, traffic, and suicides injuries, in order to reduce injury deaths associated with climate change.

Background Under the background of global warming, research on association between ambient temperature and risk of injury is needed. Objective To examine the effect of temperature on injury in Bao'an district, Shenzhen and identify the sensitive population, thereby providing a scientific basis for formulating prevention and control strategies and measures of injury. Methods The injury reports from the Injury Surveillance System and the meteorological data of Bao'an District between 2018 to 2022 were collected. The meteorological data were sourced from the fifth generation of the European Centre for Medium-Range Weather Forecasts (ECMWF) land reanalysis data. Based on time-stratified case-crossover design, conditional logistic regression combined with distributed lag nonlinear model was used to evaluate the exposure-response association between ambient temperature and injury. The stratified analyses were further conducted by gender, age, and causes of injury. Results A total of 156205 injury cases were collected from the injury surveillance sentinel hospitals in Bao'an District of Shenzhen from 2018 to 2022, and the median of daily average temperature during the same period was 20.0 ℃. The exposure-response curve showed that the risk of injury was positively correlated with temperature. The linearized analysis revealed that each 1°C increase in temperature was associated with a 1.05% (95%CI: 0.68%, 1.42%) rise in injury risk (ER). Notably, the effect was greater in females (ER=1.31%, 95%CI: 0.67%, 1.94%) than males (ER=0.92%, 95%CI: 0.47%, 1.37%). Among age groups, adults ＞60 years faced the highest risk (ER=1.91%, 95%CI: −0.36%, 4.24%). The top three temperature-associated injury risks were sharp instrument injuries (ER=2.19%, 95%CI: 1.16%, 3.22%), animal injuries (ER=1.71%, 95%CI: 0.86%, 2.56%), and blunt injuries (ER=071%, 95%CI: −0.08%, 1.51%). The impact of temperature on unintentional injuries (ER=1.11%, 95%CI: 0.72%, 1.49%) was higher than that on intentional injuries (ER=0.43%, 95%CI: −0.85%, 1.72%). Severe injuries (ER=2.20%, 95%CI: −3.09%, 7.77%) were more affected by temperature than mild injuries (ER=1.00%, 95%CI: 0.58%, 1.43%) and moderate injuries (ER=1.15%, 95%CI: 0.42%, 1.89%). Conclusion The increase in ambient temperature associates with injury occurrence, and the impact of temperature exhibits obvious heterogeneity among different populations, indicating that targeted intervention measures should be taken for different populations and types of injuries.

Objective:To explore the optimal index of rotational displacement of femoral neck fractures by modeling the axial rotational displacement of femoral neck fractures after reduction and based on X-ray projections.Methods:Six dry human femur specimens, comprising 2 males and 4 females, were utilized in the study. Design and manufacture a proximal femur ortholateral and oblique X-ray casting jigs and mounts. The femoral neck fracture was modeled on the femoral specimen, with Pauwells 30°, 50°, and 70° models (2 each) made according to Pauwells typing. The fractures were manually repositioned with residual anterior 20°, 40° and 60° axial rotational displacements. Each fracture model was projected at different angles (pedicled 40°, pedicled 20°, vertical 0°, cephalad 20°, and cephalad 40°), and the trabecular angle and Garden's alignment index of the model were measured to observe the imaging characteristics of the fracture line on the medial oblique and lateral oblique radiographs.Results:In the presence of a 20° and 40° anterior rotational displacement following reduction of a femoral neck fracture, the trabecular angle in the rotationally displaced group was not significantly different from that of the anatomically repositioned group in various projection positions. However, when a residual rotational displacement of 60° was present, the trabeculae appeared blurred at most projection angles in the Pauwells 30° and 50° models, failing to measure trabecular angles. In the Pauwells 70° fracture model, the trabecular angle in the rotational displacement group was significantly different from that in the anatomical reduction group. In anteroposterior radiographs, when the anterior rotation displacement was 60° in the Pauwells 70° group, Garden's contralateral index showed an unsatisfactory restoration (150°, 142°), whereas all rotationally displaced models in the Pauwells 30° and Pauwells 50° groups had a Garden's contralateral index of >155°, which achieved an acceptable restoration. In lateral radiographs, all rotational displacement models with Garden's alignment index>180° failed to achieve acceptable repositioning, and the larger the Pauwells angle the greater the Garden's alignment index at the same rotational displacement. In the internal oblique position with a bias towards the foot side, the image showed partial overlap between the femoral head and the shaft, making it difficult to assess the quality of the reduction. Conversely, when projected cephalad, the femoral neck appeared longer, particularly at a projection angle of 40° cephalad, allowing for clear observation of the fracture line and the anatomy of the proximal femur. The trabeculae were not well visualized in the external oblique position.Conclusion:There are limitations in applying the trabecular angle to assess the axial rotational displacement of the femoral head after reduction of femoral neck fractures. The Pauwells 70° with residual rotational anterior displacement of 60° was the only way to detect axial rotational displacement of the femoral head on anteroposterior radiographs Garden's alignment index. For the determination of axial rotational displacement of the femoral head, the Garden's alignment index on lateral radiographs provides higher reliability.

Examining mechanisms involved in the mutual regulation between the muscular system and the skeletal system, elucidating the key issues responsible for loss of muscle and bone mass and strength, and thus halting the progression of these conditions are critical measures for reducing fractures caused by falls and subsequent disability and mortality.At present, most studies have treated the muscular system and the skeletal system separately, often ignoring the mutual regulation and connections between them.This article reviews the current research progress on the mechanisms of interaction between the two systems, aiming to provide a basis for the prevention, diagnosis and treatment of disuse-related diseases in the elderly population.

Climate change has led to an increasing frequency and intensity of extreme climate events such as heat and drought extremes with considerable global public health burden. This systematic review collected 87 domestic and international studies from 2000 to 2023, considering the impacts of heat extremes, drought extremes, and compound hot-dry events on infectious diseases attributable to various transmission pathways such as waterborne, foodborne, insect-borne, airborne, and contact-transmitted diseases. Our results showed that high temperature was associated with increased transmission risks of waterborne and foodborne diseases including infectious diarrheal diseases (cholera, dysentery, typhoid, and paratyphoid) and infectious gastroenteritis; vector-borne diseases including dengue fever, Zika virus (ZIKV) disease, chikungunya fever, malaria, West Nile fever, and Rift Valley fever; airborne diseases including influenza-like diseases, influenza A, measles, and mumps; and contact-transmitted diseases including HIV/AIDS, schistosomiasis, and leptospirosis. Additionally, drought conditions also amplified the transmission risks of waterborne and foodborne diseases including cholera, Escherichia coli infection, rotavirus infection, and hepatitis E; vector-borne diseases such as scrub typhus, schistosomiasis, hemorrhagic fever with renal syndrome, and West Nile fever; airborne diseases including meningococcal meningitis, pertussis, measles, and upper respiratory infections; and contact-transmitted diseases such as HIV/AIDS. Along with global warming, the frequency of compound high temperature and drought events shows a considerably increasing trend, causing more adverse health effects than heat or drought alone. However, there is limited research quantifying their effects on infectious diseases. These associations may be mediated through temperature and precipitation on infectious disease pathogens, transmission vectors, population susceptibility, public health services, and behaviors. In the context of climate change, the increasing occurrence of compound events of high temperatures and droughts raises health concerns, and further studies are needed to enhance our understanding of the impacts of climate change on infectious diseases and improve human adaption to climate change.

Shape memory materials are intelligent materials that have the effect of remembering and recovering their original shape in response to external stimuli. The preparation methods include heat treatment and laser sintering for alloy-based memory materials, and thermoplastic methods for polymer-based and composite shape memory materials. Shape memory materials have shown great application value in the field of orthopaedics, such as fracture treatment, bone tissue engineering repair, spinal correction and joint replacement. Shape memory materials have excellent biomechanical properties, providing sustained and effective compression, support and torsion resistance during fracture treatment, as well as the advantage of reducing stress masking in internal fixation of fractures. The sustained stress exerted on the surrounding bone tissue due to environmental changes provides continuous corrective force for spinal deformity correction, and improves the durability of prostheses in arthroplasty. Shape memory materials exhibit good biocompatibility and the performance of inducing cell proliferation, making them suitable for fabricating self-adapting" scaffolds for tissue engineering. When precisely filling bone defect sites, they apply mechanical forces to the autogenous bone, stimulate the proliferation and differentiation of osteoblasts, guide bone regeneration and accelerate bone repair. Moreover, shape memory materials can be used as carriers for drug delivery and release, controlling drug release by adjusting temperature, stress and environmental factors to achieve targeted therapy. With the development of 4D printing technology, shape memory materials have extensive potential in the fields of personalized orthopaedic diagnosis and treatment as well as individualized medical device customization.

Objective:To propose a method to measure the femoral anteversion angle based on the three-dimensional model of femur.Methods:From January 2019 to December 2023, a total of 50 patients (100 femurs) with patellar instability who underwent full-length CT examination of both lower limbs in Tianjin Hospital were retrospectively analyzed, including 16 males and 34 females, aged 28.5±11.9 years (range, 16-57 years). All patients underwent CT examination of both lower limbs, and the imaging data were imported into Mimics 21.0 software as DICOM format files. The femur was extracted by the threshold segmentation function, and the 3D model of the femur was reconstructed by appropriate trimming and smoothing. Three-dimensional models of the femur from 30 patients (60 femurs) were selected and imported into 3-matic 13.0 software for labeling of anatomical points and drawing of axes. The angle between the axis of the distal femur and the axis of the proximal femur was the femoral anteversion angle. Two observers positioned the spatial coordinates of the intercondylar fossa apex, the greater trochanter apex, the center of the femoral head, the femoral through-condylar axis and the posterior condylar tangent marker points on a 3D model of the femur to compare the differences between the groups. The femoral anteversion angles measured by different three-dimensional measurement methods were compared with the clinically reported femoral anteversion angles.Results:The difference between the femoral head center and intercondylar fossa apex coordinate data of 30 patients (60 femurs) measured by the two observers was not statistically significant ( P>0.05), whereas the data for the Y-axis coordinate of the greater trochanter apex were 25.77±23.21 and 22.08±25.73, respectively, and the difference was statistically significant ( t=2.906, P=0.017). The difference between the data of femoral through condylar and posterior condylar tangential coordinates of 30 patients (60 femurs) measured by the two observers was not statistically significant ( P>0.05). Using the femoral mechanical axis as the projection direction, the angle between the transcondylar axis and the posterior condylar tangent line was 5.97°±2.02° (range, 1.48°-12.08°). The anterior tilt of the femur measured by the two observers in the femoral neck cylinder fitting method was 23.35°±7.45° and 24.94°±9.01°, respectively, and the difference was statistically significant ( t=-2.147, P=0.040). The anterior inclination of the femur measured by the two observers in the femoral head ball enlargement method was 24.63°±7.66° and 25.12°±8.84°, the difference was not statistically significant ( t=-0.820, P=0.419). Using the femoral head ball expansion method to locate the proximal femoral axis, two observers measured the anterior tilt angle of the femur in 50 patients (100 femurs) according to the method described above, which was 23.30°±9.41° and 23.57°±9.97°, respectively, without a statistically significant difference ( t=-0.664, P=0.508), both smaller than the 29.56°±8.74° measured based on two-dimensional images in the imaging report, and the difference was statistically significant ( P<0.05). Conclusion:The femoral anteversion angle measured by the angle between the axis of the femoral condyle and the axis of the femoral neck based on the three-dimensional model is accurate and effective, and the measured value is smaller than that based on the two-dimensional images in clinical practice.

Osteotomy around the knee includes medial opening wedge high tibial osteotomy (HTO), lateral closing wedge HTO, lateral opening wedge distal femoral osteotomy (DFO), medial opening wedge DFO, and double-site osteotomy. Osteotomy redistributes the knee joint pressure by correcting the lower limb alignment, which can effectively delay the progression of knee osteoarthritis. Currently, three methods are used to determine the intraoperative osteotomy angle: the pre-drilling method, wedge block insertion method, and angle-guided linkage method. Coronal plane accuracy is evaluated using the hip-knee-ankle (HKA) angle, medial proximal tibial angle (MPTA), and ratio of lower limb weight-bearing line, while sagittal plane accuracy is assessed by measuring the posterior tibial slope (PTS). Individualized osteotomy guide plate can enhance osteotomy accuracy. The preparation process includes: (1) importing low-dose CT data of both lower limbs in DICOM format into reconstruction software to establish a 3D model of both lower limbs; (2) determining the osteotomy plane and distraction angle through threshold segmentation, importing the plate model, and establishing the length and position of each screw; (3) using fused deposition modeling to layer materials through a nozzle to create the 3D object. Individualized osteotomy guide plate in osteotomy around the knee can not only improve the accuracy of surgery, but also reduce the intraoperative fluoroscopy times and the incidence of complications. The operation efficiency and postoperative rehabilitation are better than those of traditional surgery. With the continuous upgrading of new materials and the improvement of design concepts, the accuracy and efficiency of individualized osteotomy guide will be further improved. Future research will focus on improving the degree of personalization of guide plate design and simplifying the manufacturing process.