Objective To investigate the effect of postoperative reduction quality in femoral neck fracture internal fixation on mechanical properties of the femoral head from the perspective of trabecular bone biomechanics.Methods From patients who underwent hip replacement surgery for femoral neck fractures,a total of 26 femoral head slice specimens were obtained.The central axis of the primary compressive trabeculae was defined as the 0° group,with the intersection point of the primary compressive trabeculae and the femoral calcar serving as the center.By rotating the specimens to simulate different reduction angles,the cut femoral head slice specimens were randomly divided into five groups:-10°,-5°,0°,5°,and 10°,representing femoral heads with varying reduction qualities.The specimens were subjected to single compression load tests and fatigue load tests.The load was set from 70 N to 1 400 N,at a frequency of 1 Hz,with 10 000 cycles.Axial stiffness,displacement,and the number of collapse cycles were measured,to compare the biomechanical properties of femoral head specimens under different reduction qualities.Results There were differences in the axial stiffness,displacement,and number of collapse cycles among the femoral head specimens in different groups.Under 800 N load,the axial stiffness of 0° group was significantly greater than that of±10° groups(P＜0.05).The axial stiffness of 0° group was also greater than that of the±5° groups,but the differences were not statistically significant(P＞0.05).The axial stiffness of±5° groups was greater than that of±10° groups(P＜0.05).0° group had a lower displacement than±5° groups and±10° groups.However,the differences in displacement between 0° group and±5° groups were not statistically significant(P＞0.05),while the differences between the 0° group and±10° groups were statistically significant(P＜0.05).The differences in displacement between±5° groups and±10° groups were also statistically significant(P＜0.05).0° group had a significantly higher number of collapse cycles than±10° groups(P＜0.05).The number of collapse cycles in 0° group was also higher than that in±5° groups,but the differences were not statistically significant(P＞0.05).The number of collapse cycles in±5° groups was significantly higher than that±10° groups(P＜0.05).Conclusions The quality of reduction after internal fixation of femoral neck fractures significantly affects the biomechanical properties of the femoral head.This study provides a scientific basis for optimizing treatment and postoperative management,aiming to improve clinical outcomes and patients' quality of life.

Objective To investigate the effect of postoperative reduction quality in femoral neck fracture internal fixation on mechanical properties of the femoral head from the perspective of trabecular bone biomechanics.Methods From patients who underwent hip replacement surgery for femoral neck fractures,a total of 26 femoral head slice specimens were obtained.The central axis of the primary compressive trabeculae was defined as the 0° group,with the intersection point of the primary compressive trabeculae and the femoral calcar serving as the center.By rotating the specimens to simulate different reduction angles,the cut femoral head slice specimens were randomly divided into five groups:-10°,-5°,0°,5°,and 10°,representing femoral heads with varying reduction qualities.The specimens were subjected to single compression load tests and fatigue load tests.The load was set from 70 N to 1 400 N,at a frequency of 1 Hz,with 10 000 cycles.Axial stiffness,displacement,and the number of collapse cycles were measured,to compare the biomechanical properties of femoral head specimens under different reduction qualities.Results There were differences in the axial stiffness,displacement,and number of collapse cycles among the femoral head specimens in different groups.Under 800 N load,the axial stiffness of 0° group was significantly greater than that of±10° groups(P＜0.05).The axial stiffness of 0° group was also greater than that of the±5° groups,but the differences were not statistically significant(P＞0.05).The axial stiffness of±5° groups was greater than that of±10° groups(P＜0.05).0° group had a lower displacement than±5° groups and±10° groups.However,the differences in displacement between 0° group and±5° groups were not statistically significant(P＞0.05),while the differences between the 0° group and±10° groups were statistically significant(P＜0.05).The differences in displacement between±5° groups and±10° groups were also statistically significant(P＜0.05).0° group had a significantly higher number of collapse cycles than±10° groups(P＜0.05).The number of collapse cycles in 0° group was also higher than that in±5° groups,but the differences were not statistically significant(P＞0.05).The number of collapse cycles in±5° groups was significantly higher than that±10° groups(P＜0.05).Conclusions The quality of reduction after internal fixation of femoral neck fractures significantly affects the biomechanical properties of the femoral head.This study provides a scientific basis for optimizing treatment and postoperative management,aiming to improve clinical outcomes and patients' quality of life.

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.

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.

Objective To analyze the influence from material and size of the filling block on stress distributions of the tibial osteotomy model. Methods The filling blocks with three different materials (iliac bone, cancellous bone and polyetheretherketone (PEEK)) and five different sizes were established and implanted to the tibial osteotomy models, respectively. The mechanical loads were applied on the model, the stress distribution and edge displacement of the model were analyzed. Results For three kinds of materials, the stress at proximal end of the tibia and the plate, as well as edge displacement in the model implanted with filling block by iliac bone material were lower than those of the cancellous bone and PEEK, but the filling block by iliac bone material had the highest stress. When the filling blocks with different sizes were implanted in osteotomy space, the stress distribution on each part of the tibial osteotomy and edge displacement were different. Especially when the width of the filling block was reduced from 30 mm to 10 mm, the peak stress of the proximal tibia, steel plate and filling block was increased by 49. 3% , 92. 7% and 54. 4% on average. Conclusions Different filling block parameters will affect the stress distribution in different parts of the tibial osteotomy. The research results provide the theoretical basis for parameter selection of the tibial osteotomy filling block in clinic.

Objective:To investigate the efficacy and safety of the Steward Scale(S Scale)and the Modified Aldrete Scale (A Scale) for resuscitation of children undergoing gastrointestinal endoscopy with general anesthesia.Methods:A total of 199 underage children who underwent non-intubated gastrointestinal endoscopy with general anesthesia in Children′s Hospital, Zhejiang University School of Medicine from July to December 2022 were retrospectively included in this study and divided into preschool group (36 cases), low school-age group (75 cases) and high school-age group (88 cases) according to age. S Scale and A Scale were also performed to evaluate the recovery from anesthesia. The vital signs of the children and the time required for reaching the target were recorded, and the scoring efficiency and safety of the two scales were compared.Results:The time required for S Scale to reach the standard (17.50 ± 9.29) min was significantly lower than that of A Scale (20.80 ± 12.61) min, and the difference between the two groups was statistically significant ( t = 2.97, P<0.01). In the low school-age group, oxygen saturation (0.989 ± 0.010) of A Scale was higher than that of S Scale (0.980 ± 0.015), the difference was significant ( t = 2.17, P<0.05). The time required for S Scale to reach the standard was negatively correlated with age ( r = -0.385, P<0.01). There was no significant correlation between the time required for A scale to reach the standard and the children′s age ( r = -0.089, P>0.05). Conclusions:Although Steward Scale is more efficient than modified Aldrete Scale in evaluating anesthesia resuscitation in underage children undergoing gastrointestinal endoscopy with general anesthesia, modified Aldrete Scale is safer than Steward Scale and is more conducive to ensuring the life safety of children.

Objective:To retrieve, evaluate and integrate relevant evidence on the management of the developmentally supportive environment in the neonatal intensive care unit(NICU), and to provide clinical references.Methods:Evidence on NICU environmental management was retrieved from Guidelines International Network, Joanna Briggs Institute, National Institute for Health and Care Excellence, Scottish Intercollegiate Guide Network, National Guideline Clearinghouse, Registered Nurses′ Association of Ontario, Yimaitong and other Websites, BMJ Best Practice, UpToDate, Cochrane Library, PubMed, Embase, Wanfang Database, CNKI and other database.The evidence included guidelines, evidence summaries, best clinical practice manuals, expert consensus and systematic reviews.The date limit was from the establishment of the databases to March 31, 2021.Results:Totally 16 articles were involved, including 4 guidelines, 9 systematic reviews, and 3 expert consensus.Finally, 20 pieces of best evidence on four aspects were su-mmarized: sound, light, touch, and smell.There were 11 A-level recommendations and 9 B-level recommendations.The evidence suggested that health care workers should reduce noise and protect premature infants from being exposed to bright light, noxious gases, and negative touch stimuli.Besides, benign auditory and olfactory stimuli, circadian light, and mother-infant skin-to-skin contact should be used to promote the development of premature infants.Conclusions:This study is a summary of the recommendations on NICU environmental management.It is well-designed and has achieved fruitful results, showing great significance for reducing environmental stress of premature infants in the NICU.However, the current recommended methods for providing benign stimulation require validation of more high-quality, well-designed research.It is recommended that medical staff should selectively apply the evidence to clinical practice according to the actual situation.

Objective:To investigate the effect of early ambulation time on lower limbs muscle strength and fear of falling in patients with total knee arthroplasty, so as to provide basis for promoting the postoperative rehabilitation of patients undergoing total knee arthroplasty.Methods:A total of 210 patients after unilateral total knee replacement from July 2018 to December 2019 in the Second Affiliated Hospital of Soochow University were included and assigned to experimental group 1, experimental group 2 and experimental group 3 by random digits table method, each group contained 70 cases, and the patients began ambulation at 16, 20, 24 hours after knee replacement, respectively. The peak torque (PT) of knee joints flexors and extensor as well as hamstrings quadriceps ratio (H/Q) were compared among three groups at 1 week, 1 month and 3 months after knee replacement. The fall efficiency was evaluted by Modified Fall Efficacy Scale (MFES), the fear of falling rate was conducted by single item method.Results:After 1 month of knee replacement, the PT of knee joints flexor and extensor and H/Q were (18.73±5.49) N·m, (37.56±7.76) N·m, (48.08±9.19)% and (18.44±5.27) N·m, (37.04±7.07) N·m, (47.49±9.30)% in the experimental group 1 and experimental group 2, which were higher than those in the experimental group 3(16.38±2.85) N·m, (33.75±6.75) N·m, (43.48±7.17)%, the differences were statically significant ( t values were 2.316-3.057, P<0.05). After 1 week of knee replacement, the fear of falling rate were 72.3%(47/65) and MFES scores were (3.14±0.58) points in the experimental group 1, 53.7%(36/67), (3.81±0.65) points and 50.8%(32/63), (3.87±0.74) points in the experimental group 2 and experimental group 3, the fear of falling rate significantly increased and MFES scores significantly decreased in the experimental group 1 compared to the experimental group 2 and experimental group 3, the differences were statistically significant ( χ2 values were 5.780, 4.878, t values were 6.221, 6.129, P<0.05). Conclusions:Twenty hours after knee replacement is the best time for ambulation, which can shortern the time for lower limbs muscle strength recovery and reduce the risk of fear of falling.

Sarcopenia, referred to as myopenia, is a systemic syndrome characterized by decreased muscle mass and muscle strength, and decline of motor function.The elderly are a high incidence group of myopenia.With the aging of the world's population becoming increasingly severe, the incidence rate of sarcopenia has also increased, which has brought a heavy burden to the elderly family and society, and has become an important social health problem for the elderly.At present, there are more and more researches on sarcopenia, but the pathogenic factors of sarcopenia are complex and diverse.The prevention and treatment of sarcopenia still need to be further explored and studied.The establishment of an ideal animal model is the key premise and basis for the related research of sarcopenia.In this paper, the different modeling methods, advantages and disadvantages as well as the scope of application of sarcopenia animal models are described, which can provide reference and help for the subsequent animal experimental research of sarcopenia.

Objective To investigate biomechanical characteristics of femoral neck fracture with different reduction qualities. Methods Three cases of Sawbones artificial femoral models were selected, and two cases of Pauwel III femoral neck fracture were modeled. Three cannulated screws were inserted into the models in the form of inverted triangle to fix the fracture. Two cases maintained different reduction qualities (defined as Model 1 and Model 2). In the 3 third case, no modeling operation was performed (defined as intact model). Then the strain gauges were respectively pasted on regions of interest of the 3 femoral models. Finally, the femur model was applied with the vertical load on mechanical testing machine. Results When the displacement of femoral head reached 4 mm, the average load of intact model, Model 1 and Model 2 was (236.30±5.35), (196.57±3.56), (69.50±2.95) N, showing significant differences. When the displacement of femoral head reached 5 mm, the average load of intact model, Model 1 and Model 2 was (276.7±3.40)，(232.93±2.64)，(80.83±4.54) N, showing significant differences. Conclusions The lower the reduction quality of the femoral neck fracture, the weaker the ability of the femur to bear stress, the higher the probability of nonunion, re-fracture and femoral head necrosis in the process of postoperative rehabilitation.