Real-Time Detection of Unauthorized Unmanned Aerial Vehicles Using SEB-YOLOv8s.

Aiming at real-time detection of UAVs, small UAV targets are easily missed and difficult to detect in complex backgrounds. To maintain high detection performance while reducing memory and computational costs, this paper proposes the SEB-YOLOv8s detection method. Firstly, the YOLOv8 network structure is reconstructed using SPD-Conv to reduce the computational burden and accelerate the processing speed while retaining more shallow features of small targets. Secondly, we design the AttC2f module and replace the C2f module in the backbone of YOLOv8s with it, enhancing the model's ability to obtain accurate information and enriching the extracted relevant information. Finally, Bi-Level Routing Attention is introduced to optimize the Neck part of the network, reducing the model's attention to interfering information and filtering it out. The experimental results show that the mAP50 of the proposed method reaches 90.5% and the accuracy reaches 95.9%, which are improvements of 2.2% and 1.9%, respectively, compared with the original model. The mAP50-95 is improved by 2.7%, and the model's occupied memory size only increases by 2.5 MB, effectively achieving high-accuracy real-time detection with low memory consumption.

Spatiotemporal multi-omics: exploring molecular landscapes in aging and regenerative medicine.

Aging and regeneration represent complex biological phenomena that have long captivated the scientific community. To fully comprehend these processes, it is essential to investigate molecular dynamics through a lens that encompasses both spatial and temporal dimensions. Conventional omics methodologies, such as genomics and transcriptomics, have been instrumental in identifying critical molecular facets of aging and regeneration. However, these methods are somewhat limited, constrained by their spatial resolution and their lack of capacity to dynamically represent tissue alterations. The advent of emerging spatiotemporal multi-omics approaches, encompassing transcriptomics, proteomics, metabolomics, and epigenomics, furnishes comprehensive insights into these intricate molecular dynamics. These sophisticated techniques facilitate accurate delineation of molecular patterns across an array of cells, tissues, and organs, thereby offering an in-depth understanding of the fundamental mechanisms at play. This review meticulously examines the significance of spatiotemporal multi-omics in the realms of aging and regeneration research. It underscores how these methodologies augment our comprehension of molecular dynamics, cellular interactions, and signaling pathways. Initially, the review delineates the foundational principles underpinning these methods, followed by an evaluation of their recent applications within the field. The review ultimately concludes by addressing the prevailing challenges and projecting future advancements in the field. Indubitably, spatiotemporal multi-omics are instrumental in deciphering the complexities inherent in aging and regeneration, thus charting a course toward potential therapeutic innovations.

Porous microneedle patch with sustained delivery of extracellular vesicles mitigates severe spinal cord injury.

The transplantation of mesenchymal stem cells-derived secretome, particularly extracellular vesicles is a promising therapy to suppress spinal cord injury-triggered neuroinflammation. However, efficient delivery of extracellular vesicles to the injured spinal cord, with minimal damage, remains a challenge. Here we present a device for the delivery of extracellular vesicles to treat spinal cord injury. We show that the device incorporating mesenchymal stem cells and porous microneedles enables the delivery of extracellular vesicles. We demonstrate that topical application to the spinal cord lesion beneath the spinal dura, does not damage the lesion. We evaluate the efficacy of our device in a contusive spinal cord injury model and find that it reduces the cavity and scar tissue formation, promotes angiogenesis, and improves survival of nearby tissues and axons. Importantly, the sustained delivery of extracellular vesicles for at least 7 days results in significant functional recovery. Thus, our device provides an efficient and sustained extracellular vesicles delivery platform for spinal cord injury treatment.

Controlled delivery of a neurotransmitter-agonist conjugate for functional recovery after severe spinal cord injury.

Despite considerable unmet medical needs, effective pharmacological treatments that promote functional recovery after spinal cord injury remain limited. Although multiple pathological events are implicated in spinal cord injuries, the development of a microinvasive pharmacological approach that simultaneously targets the different mechanisms involved in spinal cord injury remains a formidable challenge. Here we report the development of a microinvasive nanodrug delivery system that consists of amphiphilic copolymers responsive to reactive oxygen species and an encapsulated neurotransmitter-conjugated KCC2 agonist. Upon intravenous administration, the nanodrugs enter the injured spinal cord due to a disruption in the blood-spinal cord barrier and disassembly due to damage-triggered reactive oxygen species. The nanodrugs exhibit dual functions in the injured spinal cord: scavenging accumulated reactive oxygen species in the lesion, thereby protecting spared tissues, and facilitating the integration of spared circuits into the host spinal cord through targeted modulation of inhibitory neurons. This microinvasive treatment leads to notable functional recovery in rats with contusive spinal cord injury.

Silicate Nanoplatelets Promotes Neuronal Differentiation of Neural Stem Cells and Restoration of Spinal Cord Injury.

Neural stem cell (NSC) transplantation has been suggested as a promising therapeutic strategy to replace lost neurons after spinal cord injury (SCI). However, the low survival rate and neuronal differentiation efficiency of implanted NSCs within the lesion cavity limit the application. Furthermore, it is difficult for transplanted cells to form connections with host cells. Thus, effective and feasible methods to enhance the efficacy of cell transplantation are needed. In this study, the effect of Laponite nanoplatelets, a type of silicate nanoplatelets, on stem cell therapy is explored. Laponite nanoplatelets can induce the neuronal differentiation of NSCs in vitro within five days, and RNA sequencing and protein expression analysis demonstrated that the NF-κB pathway is involved in this process. Moreover, histological results revealed that Laponite nanoplatelets can increase the survival rate of transplanted NSCs and promote NSCs to differentiate into mature neurons. Finally, the formation of connections between transplanted cells and host cells is confirmed by axon tracing. Hence, Laponite nanoplatelets, which drove neuronal differentiation and the maturation of NSCs both in vitro and in vivo, can be considered a convenient and practical biomaterial to promote repair of the injured spinal cord by enhancing the efficacy of NSC transplantation.

3D printing method for bone tissue engineering scaffold.

3D printing technology is an emerging technology. It constructs solid bodies by stacking materials layer by layer, and can quickly and accurately prepare bone tissue engineering scaffolds with specific shapes and structures to meet the needs of different patients. The field of life sciences has received a great deal of attention. However, different 3D printing technologies and materials have their advantages and disadvantages, and there are limitations in clinical application. In this paper, the technology, materials and clinical applications of 3D printed bone tissue engineering scaffolds are reviewed, and the future development trends and challenges in this field are prospected.

Comparison and analysis of skiing injuries at ski resorts in Chongli, China and Japan / 中华创伤杂志(英文版)

PURPOSE@#The rapid development of winter sports requires investigation on injuries in Chongli district, Zhangjiakou city, one of the ski sites of the 2022 Winter Olympics. Careful evaluation is required to observe which injuries are caused under what circumstances, and then we can make corresponding preventive measures and recommendations based on the results.@*METHODS@#In this retrospective study, the data of injury cases at ski resorts in China (Chongli district) and Japan were analyzed to provide a reference for the ongoing injury prevention at ski resorts. We collected data on injuries at Wanlong and Fulong ski resorts in Chongli district during the 2017-2018 and 2018-2019 ski seasons. We referred to the skiing injury report issued in February 2020 of a nationwide ski safety statistical service - Japan Ski Safety Association. The causes of injury and specific injured body parts were analyzed based on the data of Chinese and Japanese ski resorts. Statistical significance has been calculated using the Chi-square test.@*RESULTS@#During the 2019-2020 ski season in Japanese ski resorts, the number of reported injuries per 10,000 skiers was 0.93, of which 457 (17.3%) were over 50 years old, accounting for a large proportion of injuries, meanwhile in Chongli ski resort, the injury rate of skiers aged 50 and over was 7.1%. The knee joint (23.7% at Wanlong ski resort and 28.4% in Japanese ski resorts) was the most injured body part among Chongli and Japanese skiers. Among snowboarders, shoulder joint injury (17.7% in Japanese ski resorts) was the most common, and injury on hands and fingers (16.3% in Wanlong ski resorts) was the most common. Head injury rates are similar in Chongli, China and Japanese ski resorts (8.2% and 8.7%, respectively).@*CONCLUSION@#Our analysis demonstrated that injury data recorded among young skiers was higher in Chinese ski resorts (Chongli district) than that in Japanese ski resorts, and elderly skiers made up a larger proportion of skiing injuries in Japanese resorts. Thus, according to our research, the protection of knee joints, shoulder joints, and hands and fingers should be taken seriously. It should pay attention to the teaching of ski poles (for finger protection), and use protective devices such as knee pads, helmets, etc.

The Small Molecule Drug BNTA Alleviates Osteoarthritis Caused by High Cholesterol by Upregulating Insig1 / 中国生物化学与分子生物学报

Osteoarthritis (OA) is a common degenerative disease of the motor system with a high morbidity and disability rate. The pathogenesis of OA is not clear at present. Previous studies believe that the pathogenesis of OA is mainly related to trauma factors, while recent studies have shown that metabolic factors, including abnormal cholesterol metabolism, are also closely related to OA. The treatment of OA is mainly symptomatic treatment at the early stage and surgical treatment at the late stage, and there is no specific drug. Previously, BNTA, a small molecule drug with cartilage protective effects, has been shown to have a good effect on OA caused by trauma, but its effect on OA caused by high cholesterol remains unclear. In order to explore the therapeutic effect of BNTA on OA caused by high cholesterol and its mechanism, the OA model of rats was constructed by adopting high cholesterol diets, and paraffin sections of knee joints were taken for histological evaluation. Lipid accumulation in chondrocytes of rats was assessed by oil red O staining. The expression of genes and proteins related to anabolism, catabolism and cholesterol metabolism in chondrocytes was assessed by RT-qPCR, immunofluorescence and immunohistochemistry. The results showed that BNTA could alleviate OA pathological manifestations and improve the OARSI (Osteoarthritis Research Society International) score in the OA model of high cholesterol rats. In rat chondrocytes, BNTA can promote the expression of anabolism-related genes col2, sox9 and acan, inhibit the expression of catabolism-related genes mmp13 and adamts5, and improve the lipid accumulation caused by high cholesterol in rat chondrocytes. BNTA can up-regulate Insig1 expression in rat chondrocytes and the OA model of high cholesterol rats. This study confirmed that high cholesterol can aggravate OA in vivo and in vitro, and can increase lipid accumulation in rat chondrocytes. Taken together, BNTA can alleviate OA phenotypes induced by high cholesterol and improve abnormal lipid accumulation in chondrocytes, possibly by inhibiting cholesterol biosynthesis in cells by upregulating Insig1, thereby alleviating abnormal lipid accumulation.

Cdkn2a Tracer Mice: A Novel Model to Study Cellular Senescence in Post-traumatic Osteoarthritis / 中国生物化学与分子生物学报

Osteoarthritis (OA) is one of the most common geriatric motor system diseases in the clinical practice. Aging, whose hallmark is cellular senescence, is an important factor leading to the occurrence and development of OA, but its exact role in the pathological development of OA is not completely clear. Studies have proved that targeting senescence can effectively treat aging-related diseases. In this study, the heterozygous mouse model of Cdkn2a-e (Luc-2A-tdTomato-2a-CreerT2-Wpre-PA)1 was established by the CRISPR/ Cas9 technique. The expression of Cdkn2a (p16, p16INK4a), a classical marker of senescence, can be traced in vivo in mice. We then utilized anterior cruciate ligament transection (ACLT) to induce OA in Cdkn2a mice, and we hope to verify the relationship between aging and the occurrence and development of OA and visualize aging changes during OA development through the mice model. In this study, 10-12 weeks old Cdkn2a mice were randomly divided into no surgery control group, sham operation group and ACLT group. OA model was constructed in mice by ACLT operation. After surgery for 4 weeks, animals were collected for fluorescence imaging detection in vivo, which showed that local fluorescence expression of Cdkn2a increased in knee joints of mice in the ACLT group four weeks after surgery (P < 0. 05) . The Safranin O-Fast Green Staining of mouse knee tissue sections showed degeneration of the knee cartilage in the ACLT group at 4 weeks after surgery (P < 0. 05) . Immunohistochemical staining of Cdkn2a was performed on the knee tissue of mice. Compared with the other two groups, Cdkn2a staining on the cartilage surface of the knee tissue of mice in the ACLT group was deeper. The results showed that the OA model induced by surgery showed local aging, which further verified the relationship between aging and OA. At the same time, the Cdkn2a tracer mouse model can reflect the aging progress of mice in vivo, with combination of imaging examinations, so that the occurrence and progress of the relationship between aging and OA can be observed in real time. This heterozygous mouse model of Cdkn2a-e(Luc-2A-tdTomato-2a-CreerT2-Wpre-PA) 1 is not only useful for mechanism research of aging and OA diseases, but also beneficial for finding more potential therapy targets to OA and aging.

Meniscus repair with simultaneous anterior cruciate ligament reconstruction: Clinical outcomes, failure rates and subsequent processing / 中华创伤杂志(英文版)

PURPOSE@#To retrospectively analyze the clinical outcomes of meniscus repair with simultaneous anterior cruciate ligament (ACL) reconstruction and explore the causes of failure of meniscus repair.@*METHODS@#From May 2013 to July 2018, the clinical data of 165 patients who were treated with meniscus surgery and simultaneous ACL reconstruction, including 69 cases of meniscus repair (repair group) and 96 cases of partial meniscectomy (partial meniscectomy group) were retrospectively analyzed. The exclusion criteria were as follows: (1) ACL rupture associated with fracture, collateral ligament injury, or complex ligament injury; (2) a history of knee surgery; or (3) a significant degree of osteoarthritis. The 69 patients in the repair group were divided into the non-failure group (62 cases) and the failure group (7 cases) depending on the repair effect. Postoperative outcomes of the repair group and the partial meniscectomy group were compared. General conditions and postoperative outcomes of the failure group and the non-failure group were compared. During the median follow-up period of 28 months (range, 4 - 65 months) after the second arthroscopy, postoperative outcomes of seven patients in the failure group were summarized. SPSS 25.0 statistical software was used for statistical analysis. A p value less than 0.05 was considered statistically significant.@*RESULTS@#Seven patients in the failure group who underwent the second arthroscopy were followed up for (30 ± 17.4) months and their postoperative outcomes were summarized. Compared with the partial meniscectomy group, the International Knee Documentation Committee scores of patients in the repair group improved significantly (p = 0.031). Compared with the non-failure group, more patients in the failure group were younger than 24 years (p = 0.030). The median follow-up period was 39.5 months. All patients recovered well after subsequent partial meniscectomy and relieved clinical symptoms. Visual analog scale scores decreased significantly (p = 0.026), and the International Knee Documentation Committee and Lysholm scores improved significantly (p = 0.046 for both).@*CONCLUSION@#The failure rate of meniscus repair in this study was 10.1% (7/69), all of which were medial meniscus tears. However, the surgical outcomes of ACL reconstruction were not affected, and there might be a role for graft protection. Therefore, meniscus retears can be successful treated by performing subsequent partial meniscectomy in patients with repair failure.

3D Printing of Layered Gradient Pore Structure of Brain-like Tissue.

The pathological research and drug development of brain diseases require appropriate brain models. Given the complex, layered structure of the cerebral cortex, as well as the constraints on the medical ethics and the inaccuracy of animal models, it is necessary to construct a brain-like model in vitro. In this study, we designed and built integrated three-dimensional (3D) printing equipment for cell printing/culture, which can guarantee cell viability in the printing process and provide the equipment foundation for manufacturing the layered structures with gradient distribution of pore size. Based on this printing equipment, to achieve the purpose of printing the layered structures with multiple materials, we conducted research on the performance of bio-inks with different compositions and optimized the printing process. By extruding and stacking materials, we can print the layered structure with the uniform distribution of cells and the gradient distribution of pore sizes. Finally, we can accurately print a structure with 30 layers. The line width (resolution) of the printed monolayer structure was about 478 mm, the forming accuracy can reach 97.24%, and the viability of cells in the printed structure is as high as 94.5%.

Effects of visual restoration on dynamic plantar pressure features in elder individuals / 北京大学学报(医学版)

OBJECTIVE@#To analyze the effects of visual restoration after cataract surgery on plantar pressure and biomechanics of foot in elder individuals.@*METHODS@#Thirty-two patients [male/female 5/27, (70.1±5.2) years old] with age-related cataract were recruited between October 2016 and December 2019. The footscan system was employed to record the data of plantar pressure during level walking before and 1-month after the cataract surgery. Parameters of peak pressure (PP), impulse (I), pressure-time integral (PTI) and time to peak pressure (TPP) from the regions of the 1st toe (T1), 2nd to 5th toes (T2-5), 1st to 5th metatarsal heads (M1-M5), midfoot (MF), medial hindfoot (HM) and lateral hindfoot (HL) were analyzed respectively.@*RESULTS@#Post-operatively, the visual function was effectively reconstructed with improved visual acuity in both eyes (Z=-4.878, -4.801; P < 0.001). The PP (t=2.266, P=0.031) and I (t=2.152, P=0.039) values in M2 region on the dominant side (right foot) increased statistically at post-operative phase, while the changes of pressure and temporal para-meters in other regions remained stable. There was laterality in plantar pressure at pre-operative phase, manifested as greater PP values in M1, M2, MF, and HM regions on the dominant sides (t=-2.414, -2.478, -2.144, -5.269; P < 0.05), greater PP values in T1, M3, M5 and HL regions on the non-dominant sides (t=4.830, 3.155, 2.686, 3.683; P < 0.05), greater I values in M1, MF, and HM regions on the dominant sides (t=-2.380, -2.185, -5.320; P < 0.05) and greater I values in T1, M3, M5 and HL regions on the non-dominant sides (t=4.489, 2.247, 2.838, 3.992; P < 0.05). post-operatively, the pressure tended to be compatible between the two sides in regions of M3 and MF, while the magnitude of laterality in regions of M1 (ZPP△= -2.721, P=0.007; ZI△=-2.581, P=0.010), M2 (ZPP△=-2.674, P=0.007; ZI△=-2.375, P=0.018) and M5 (ZPP△=1.991, P=0.046; ZI△=2.150, P=0.032) was further increased.@*CONCLUSION@#Changes in plantar pressure after cataract surgery were characterized as increased pressure in the 2nd metatarsal head area on the dominant side. Visual restoration might intensify the laterality in the medial of forefoot on the dominant side and the lateral of forefoot on the non-dominant side.

Changes of electroencephalography power spectrum during joint position perception test after anterior cruciate ligament rupture / 北京大学学报(医学版)

OBJECTIVE@#To measure the electroencephalography (EEG) of the patients with anterior cruciate ligament (ACL) rupture when performing joint position perception movement task, to compare the differences between the ACL rupture side and the unaffected side, to identify the EEG change in the power spectrum caused by the ACL rupture, and to provide evidence for the diagnosis, treatment and rehabi-litation for ACL injury as well as knee instability.@*METHODS@#Sixteen male patients, selected from the Department of Sports Medicine, Peking University Third Hospital from November 2014 to April 2015, with only ACL rupture on one side used isokinetic muscle strength testing equipment were enrolled in the study to perform unilateral active knee joint positional movement and passive knee joint positional movement tasks. EEG was recorded to compare between the affected and unaffected limb of ACL rupture patients when doing single leg movement tasks, including passive knee joint position test and active knee joint position sensation test. The target position of the active knee joint position movement task and the passive knee joint position movement task was 30 degrees of knee flexion.@*RESULTS@#During the passive knee joint position test, there was no significant difference in EEG power spectrum of Delta[F (1, 15)=0.003, P=0.957, ηP2 =0.001], Theta[F (1, 15)=0.002, P=0.962, ηP2 < 0.001], Alpha[F (1, 15)=0.002, P=0.966, ηP2 =0.001], Beta[F (1, 15)=0.008, P=0.929, ηP2 =0.001] at Fz, Cz, and Pz between the affected and unaffected limbs in the ACL patients. During the active knee joint position movement task, the EEG power spectrum of Delta, Theta, Alpha, Beta at Fz and Cz location, on the affected side was significant higher than on the unaffected side.@*CONCLUSION@#This study compared the differences between the ACL rupture side and the unaffected side during active knee position movement task and passive knee position movement task, and identifyied the EEG changes in the power spectrum caused by the ACL rupture, It was found that the central changes caused by unilateral ACL rupture still existed during contralateral (unaffected) side movement. The EEG power spectrum of the affected side during active exercise was significantly higher than that of the unaffected side This study provides new electrophysiological evidence for the study of ACL injury.

Finite element analysis of the graft stresses after anterior cruciate ligament reconstruction / 北京大学学报(医学版)

OBJECTIVE@#To explore the stress distribution characteristics of the graft after anterior cruciate ligament (ACL) reconstruction, so as to provide theoretical reference for the surgical plan of ACL reconstruction.@*METHODS@#Based on 3D MRI and CT images, finite element models of the uninjured knee joint and knee joint after ACL reconstruction were established in this study. The uninjured knee model included femur, tibia, fibula, medial collateral ligament, lateral collateral ligament, ACL and posterior cruciate ligament. The ACL reconstruction knee model included femur, tibia, fibula, medial collateral ligament, lateral collateral ligament, ACL graft and posterior cruciate ligament. Linear elastic material properties were used for both the uninjured and ACL reconstruction models. The elastic modulus of bone tissue was set as 17 GPa and Poisson' s ratio was 0.36. The material properties of ligament tissue and graft were set as elastic modulus 390 MPa and Poisson's ratio 0.4. The femur was fixed as the boundary condition, and the tibia anterior tension of 134 N was applied as the loading condition. The stress states of the ACL of the intact joint and the ACL graft after reconstruction were solved and analyzed, including tension, pressure, shear force and von Mises stress.@*RESULTS@#The maximum compressive stress (6.34 MPa), von Mises stress (5.9 MPa) and shear stress (1.83 MPa) of the reconstructed ACL graft were all at the anterior femoral end. It was consistent with the position of maximum compressive stress (8.77 MPa), von Mises stress (8.88 MPa) and shear stress (3.44 MPa) in the ACL of the intact knee joint. The maximum tensile stress of the graft also appeared at the femoral end, but at the posterior side, which was consistent with the position of the maximum tensile stress of ACL of the uninjured knee joint. More-over, the maximum tensile stress of the graft was only 0.88 MPa, which was less than 2.56 MPa of ACL of the uninjured knee joint.@*CONCLUSION@#The maximum compressive stress, von Mises stress and shear stress of the ACL graft are located in the anterior femoral end, and the maximum tensile stress is located in the posterior femoral end, which is consistent with the position of the maximum tensile stress of the ACL of the uninjured knee joint. The anterior part of ACL and the graft bore higher stresses than the posterior part, which is consistent with the biomechanical characteristics of ACL.

Mid-to-long term clinical outcomes and predictors after anterior cruciate ligament revision / 北京大学学报(医学版)

OBJECTIVE@#To assess the mid-to-long term clinical outcomes after anterior cruciate ligament (ACL) revision surgery and to analyze their predictors.@*METHODS@#The medical records of 235 patients undergoing ACL revision surgery between Jan. 2001 and Dec. 2015 at Department of Sports Medicine, Peking University Third Hospital were reviewed. Data were collected including demographic information, information related to revision surgery (time and cause of graft failure, date of revision surgery, surgical technique, combined injuries and management, etc.), as well as information related to primary ACL reconstruction (time, cause and mechanism of first-time ACL rupture, date of primary ACL reconstruction, surgical technique, combined injuries and management, etc.). Patients were followed up at least 2 years after revision surgery for clinical outcomes [Tegner score, Lysholm score, and International Knee Documentation Committee (IKDC) subjective knee score]. Post-revision surgeries on the involved knee and the contralateral knee joint were also documented. Multivariate regression model was used to analyze the predictors of clinical outcomes after ACL revision surgery.@*RESULTS@#A total of 166 (70.63%) patients were followed up at a mean of (4.44±2.40) years (2.03-14.63 years). Clinical outcomes improved significantly at the last follow-up from pre-operative level, with the Lysholm, Tegner, and IKDC scores improving from 70.51±21.25, 3.39±1.77, 63.78±15.04 to 88.64±14.36, 4.67±1.739, 80.23±13.31 (P < 0.05), respectively. Three (1.81%) patients experienced infection while 39 (23.49%) patients underwent surgery after revision surgery during the follow-up. Compared with that those occurred during sports, graft failure that occurred during daily activities or due to surgical technical errors that led to poorer clinical outcomes, with the Lysholm, Tegner, and IKDC scores of 9.90 (95%CI: 1.49-18.31), 1.41 (95%CI: 0.10-2.72), 10.35 (95%CI: 0.17-20.54), and 8.53 (95%CI: 1.31-15.75), 1.28 (95%CI: 0.14-2.43), 9.39 (95%CI: 1.03-17.74) lower, respectively. Compared with antero-medial portal, transtibial technique for placement of the femoral bone tunnel showed poorer Lysholm scores of 11.18 (95%CI: 4.73-17.63, P=0.001). Concurrent repair of medial meniscus yielded higher IKDC scores of 11.06 (95%CI: 1.21-20.92, P=0.029) than those with intact medical meniscus. Other factors showed no significant effect.@*CONCLUSION@#ACL revision surgery is able to restore knee stability and improve knee function. Graft failure caused by sports, concurrent repair of medical meniscus and antero-medial portal technique predicts better outcomes after revision surgery.

Management algorithm for septic arthritis after anterior cruciate ligament reconstruction / 北京大学学报(医学版)

OBJECTIVE@#To summarize the experience in the diagnosis and management of septic arthritis after anterior cruciate ligament reconstruction.@*METHODS@#A retrospective review was conducted of all the arthroscopic anterior cruciate ligament reconstructions performed at Department of Sports Medicine, Peking University Third Hospital between January 2001 and December 2020. In the study, 65 of 27 867 patients experienced postoperative septic arthritis. The incidence, presentation, laboratory results, treatment, and outcome of all the infected patients were analyzed. The experiences of diagnosis and management of septic arthritis after anterior cruciate ligament reconstruction were summarized.@*RESULTS@#A total of 27 867 anterior cruciate ligament reconstructions were performed at our department between January 2001 and December 2020. In the study, 65 (0.23%) patients were identified with postoperative septic arthritis. The most common symptoms of the infected patients were fever (38.7±0.5) ℃, knee swelling, pain, and restricted motion. The mean peripheral white blood cell count (WBC) was (9.2±2.6)×109/L (range 4.2×109/L-19.4×109/L), with (72.5±6.3) % (range 54.9%-85.1%) polymorphonuclear neutrophils (N). The mean erythrocyte sedimentation rate (ESR) was (59.9±24.1) mm/h (range 9-108 mm/h), C-reactive protein (CRP) was (10.9±5.7) mg/dL (range 1.2-30.8 mg/dL), and fibrinogen (FIB) level was (7.0±1.6) g/L (range 3.7-10.8 g/L). All of the laboratory results were statistically higher in the infection group compared with the normal postoperative group (P＜0.001). The synovial white blood cell count (SWBC) of aspirated knee joint fluid was (45.0±29.8)×109/L (range 7.1×109-76.5×109/L). Polymorphonuclear cell percentage (PMNC) was (90.27±7.86) % (range 60%-97%). In the study, 45 patients (69.2%) had positive aspirate cultures. Microbiology showed coagulase-negative Staphylococcus (CNS) and Staphylococcus aureus (SA) were the most common bacterium (34 cases and 7 cases, individually). There were 26 methicillin-resistant Staphylococcus. Both conservative (16 patients) and operative (49 patients) treatments were effective, but conservative group had a longer recovery time (5.6 d vs. 1.6 d, P=0.042).@*CONCLUSION@#Septic arthritis after arthroscopic anterior cruciate ligament reconstruction is a rare but potentially devastating complication. The correct diagnosis relies on synovial fluid analysis and bacterial culture. Our proposed treatment protocol is arthroscopic debridement and antibiotic therapy as quickly as possible.

Comparison of acute sports injury between recreational skiers and skiers / 北京大学学报(医学版)

OBJECTIVE@#To compare and analyze the difference between the injuries of recreational skiers in public ski resorts and those of skiing athletes in official competitions, and to explore the suggestions of medical insurance for these two types of skiers.@*METHODS@#The injury data of recreational skiers in Chongli District, Zhangjiakou City, Hebei Province during 2018-2019 and 2019-2020 snow seasons, and the injury data of skiers in two official international skiing competitions during 2019-2020 snow season and domestic test events in Chongli District of 2021 Winter Olympic Games were analyzed retrospectively, and the similarities and differences were compared.@*RESULTS@#A total of 1 187 injuries occurred to recreational skiers in the two public ski resorts during the 2018-2019 snow season, with an injury rate of 0.3%.There were 1 277 injury sites in total, and the most frequent injury sites were head and neck (230 cases, 18.0%), followed by knee joint (204 cases, 16.0%) and lower extremity (131 cases, 10.3%). Thirty-one skiers were injured in the two official international skiing competitions in the 2019-2020 and 2020-2021 snow season, and in the domestic test competitions in the 2021 Winter Olympic Games, and the injury rates were 11.5%, 17.2% and 12.0%, respectively. There were 37 injury sites in total, among which 11 (29.7%) were in the head and neck, followed by 6 (16.2%) in the knee joint and 5 (13.6%) in the chest, rib and abdomen.@*CONCLUSION@#In order to better guarantee the safety of skiers and timely provide corresponding medical help, safety facilities and technical guidance should be added to the snow resort for leisure skiing, and medical stations should be set up in the snow resort. As the formal ski racing for skiing athletes during the game has 30 to 80 times higher injury ratesthan recreational skiers, and compared with the recreational skiing, head and neck injury rate is higher, and the damage is much heavier, more complete first aid facilities and experienced medical workers are, needed so the field should be equipped with the circuit inside the quantities, track fixed outside the clinic, surrounding referral hospitals set up trauma centers to provide athletes with more timely medical care.

Role of ski injury treatment system between the ski resort medical station of Winter Olympics and the nearby medical care hospital / 北京大学学报(医学版)

OBJECTIVE@#To make a retrospective analysis of the situation and process of treating skiers' injuries in the medical station of the Wanlong ski resort in Chongli and the nearest treatment hospital, and to provide a basis for the establishment and optimization of the treatment process between the medical station of the Winter Olympics ski resort and the nearest treatment hospital, and to gain experience for medical security of mass skiing.@*METHODS@#The data of all ski injuries in Chongli District were collected from the medical station of the Wanlong ski resort during the 2018-2019 snow season (November 2018 to April 2019) and the nearest treatment hospital during two periods (March 2019, and November 2019 to January 2020). The differences of injury causes, injury types, injury sites, and treatment effects of the injured skiers were analyzed.@*RESULTS@#A total of 755 cases of ski injuries were recorded in the medical station of Wanlong ski resort, the estimated incidence of injury was 2.02‰ per day. The nearest treatment hospital treated a total of 838 injured skiers from different ski resorts in Chongli District in the two periods. In the records of the ski resort medical station, the main causes of injury were technical defects and turnovers (53.6%). Knee joint injury rate was the highest (18.7%), followed by head and neck (12.9%) and lower limb (11.9%). The number of injuries on intermediate roads was the highest (40.0%), the greatest number of injuries (81.2%) occurred when the age of skiing was less than 5 years. In the records of the nearest treatment hospital, the injury types were fracture or fissure fracture, contusion and trauma, and muscle and soft tissue injury, accounting for 30.5%, 27.4%, and 21.2% respectively. 9.6% of the injured took the snow field ambulance to the hospital, and 50% of them suffered from fractures or fissure fractures.@*CONCLUSION@#The injury rate of skiing in the 2018-2019 snow season of the Wanlong ski resort in Chongli was higher than that reported by foreign literature. Severe trauma (including severe fractures and concussions) could occur and patients needed to be transferred to the nearest hospital for treatment. The ski resort medical station and the nearest treatment hospital should be strengthened with adequate medical staff and equipment, and promote cooperation in the timely referral of seriously injured patients, the organization and construction of ski patrols and the medical security of large-scale competitions, thus playing an important role in forming a grassroots network of medical security and treatment system for skiing.

Characteristics and related factors of plantar pressure in the chronic ankle instability individuals / 北京大学学报(医学版)

OBJECTIVE@#To analyze characteristics and related factors of the plantar pressure during the level walking and single leg standing in the chronic ankle instability (CAI) individuals.@*METHODS@#From April 2019, 75 CAI individuals and 40 healthy individuals were enrolled in this study. Both of the static and dynamic plantar pressure were measured during six times level walking and three times single leg standing testing. The data including peak force, time to peak force in various foot contact areas and the time to boundary (TTB) and velocity of center of pressure (COP) were measured and compared between the affected side and the unaffected side and between the CAI cases and the healthy individuals. The correlations between the plantar pressure and the gender, Beighton score, affected side and body mass index (BMI) were analyzed.@*RESULTS@#The characteristics of plantar pressure distribution in the CAI individuals included: (1) During the level walking, the affected side showed the similar pressure contribution as the unaffected side (P>0.05). While compared with healthy individuals, there was a significantly higher peak force in the 5th metatarsal area (t=-3.86, P=0.03) of the affected side, lower peak force in the 1st (t=2.99, P=0.02), 2nd metatarsal head areas (t=2.09, P=0.01) of the affected side, medial hindfoot areas of both sides (affected, t=2.33, P=0.01; unaffected, t=3.74, P=0.02) and toes areass of both sides (affected, t=2.23, P=0.01; unaffected, t=3.28, P=0.02) and a delay to peak force in the 4th metatarsal head area (t=3.33, P=0.01) of the affected side. (2) During the single leg standing, the CAI individuals showed significantly worse balance control in the anterior/posterior direction (P < 0.05) and lateral/medial direction (P < 0.05) compared with the healthy controls, and the affected side had more severe balance control deficit in the lateral/medial direction (P < 0.05). (3) The women (P < 0.05) and the individuals with higher Beighton scores (P < 0.05) showed worse balance control deficit in the lateral/medial direction.@*CONCLUSION@#CAI individuals showed significantly a more lateral shifted plantar distribution during the level walking compared with the healthy individuals and the tendency was worse on the affected sides, and showed worse balance control in the anterior/posterior direction and lateral/medial direction during the single leg standing. The women and those with generalized ligament laxity showed significantly worse balance control.