Osteoporotic bone defect (OBD) is a serious bone defect resulting from the disruption of the bone structural integrity due to fractures in osteoporotic conditions. OBD not only leads to increased risk of fractures, delayed bone healing, functional loss, and chronic pain, but also reduces patients′ quality of life and even elevates the risk of death. Currently, OBD is primarily treated with systemic medications and local bone grafting. However, drug therapy is often associated with serious side effects, low bioavailability and poor bone targeting performance, while bone grafting is limited by high infection rate in donor areas, scarce bone source and severe immune rejection. Therefore, there is an urgent need for new bone repair materials to improve the bone microenvironment and stimulate bone regeneration. Bioactive molecules have shown great potential in modulating OBD treatment, but their application in organisms is hindered by their low bioavailability and short half-life. Hydrogels have emerged as an ideal vehicle to address these limitations by prolonging the retention time and half-life of bioactive molecules at the site of injury, reducing side effects and promoting cell adhesion under physiological conditions. All these advantages promote osteoblast proliferation and differentiation, providing a promising solution for OBD treatment. However, hydrogels still face challenges such as uncontrolled degradation rate, inadequate mechanical properties and poor osseointegration ability. To this end, the authors systematically elucidated the challenges of hydrogels in OBD treatment and proposed countermeasures, aiming to provide a reference for the research and clinical application of hydrogels.

Nonunion of osteoporotic vertebral fractures (OVF), predominantly affecting the elderly, can lead to intractable pain, vertebral collapse, progressive kyphotic deformity, and neurological impairment, significantly compromising patients′ quality of life. There exists considerable debate on diagnosis and management of OVF, encompassing key issues such as clinical diagnosis and staging criteria for nonunion, surgical indications and procedure selection, and postoperative rehabilitation planning. Currently, there lacks standardized clinical guideline and expert consensus on the diagnosis and management of OVF nonunion in China. To address this gap, Minimally Invasive Surgery Group of Chinese Orthopedic Association, Osteoporosis Committee of Chinese Association of Orthopedic Surgeons, Prevention and Rehabilitation Committee for Osteoporosis of Chinese Association of Rehabilitation Medicine and Minimally Invasive Orthopedic Surgery Branch of China Association for Geriatric Care jointly organized domestic experts in spinal surgery, endocrinology, and rehabilitation to formulate the Clinical guideline for the diagnosis and treatment for nonunion of osteoporotic vertebral fractures ( version 2025), based on existing literature and clinical experience and adhering to principles of scientific rigor and practicality. The guideline provided 13 evidence-based recommendations encompassing diagnosis and treatment of OVF nonunion, aiming to standardize its clinical management.

BACKGROUND:The imbalance between bone resorption and bone formation in microgravity environments leads to significant bone loss in astronauts.Current research indicates that bone loss under microgravity conditions is the result of the combined effects of various cells,tissues,and systems. OBJECTIVE:To review different biological effects of microgravity on various cells,tissues,or systems,and summarize the mechanisms by which microgravity leads to the development of osteoporosis. METHODS:Databases such as PubMed,Web of Science,and the Cochrane Database were searched for relevant literature from 2000 to 2023.The inclusion criteria were all articles related to tissue engineering studies and basic research on osteoporosis caused by microgravity.Ultimately,85 articles were included for review. RESULTS AND CONCLUSION:(1)In microgravity environment,bone marrow mesenchymal stem cells tend to differentiate more into adipocytes rather than osteoblasts,and hematopoietic stem cells in this environment are more inclined to differentiate into osteoclasts,reducing differentiation into the erythroid lineage.At the same time,microgravity inhibits the proliferation and differentiation of osteoblasts,promotes apoptosis of osteoblasts,alters cell morphology,and reduces the mineralization capacity of osteoblasts.Microgravity significantly increases the number and activity of osteoclasts.Microgravity also hinders the differentiation of osteoblasts into osteocytes and promotes the apoptosis of osteocytes.(2)In a microgravity environment,the body experiences changes such as skeletal muscle atrophy,microvascular remodeling,bone microcirculation disorders,and endocrine disruption.These changes lead to mechanical unloading in the bone microenvironment,insufficient blood perfusion,and calcium cycle disorders,which significantly impact the development of osteoporosis.(3)At present,the mechanism by which microgravity causes osteoporosis is relatively complex.A deeper study of these physiological mechanisms is crucial to ensuring the health of astronauts during long-term space missions,and provides a theoretical basis for the prevention and treatment of osteoporosis.

BACKGROUND:The extracellular-regulated protein kinase 5(ERK5)signaling protein is essential for the survival of organisms,and resveratrol can promote osteoblast proliferation through various pathways.However,whether resveratrol can regulate osteoblast function through the ERK5 signaling protein needs further verification. OBJECTIVE:To explore the regulatory effect of ERK5 on the proliferation of MC3T3-E1 cells and related secreted proteins,and to further verify whether resveratrol can complete the above process by activating ERK5. METHODS:Mouse MC3T3-E1 preosteoblasts were treated with complete culture medium,XMD8-92(an ERK5 inhibitor),epidermal growth factor(an ERK5 activator),resveratrol alone,XMD8-92+EGF,and resveratrol+XMD8-92,respectively.Western blot assay was used to detect the expression of ERK5 and p-ERK5 proteins,proliferation-related proteins Cyclin D1,CDK4 and PCNA,and osteoblast-secreted proteins osteoprotegerin and receptor activator of nuclear factor-κB ligand in MC3T3-E1 cells of each group.The fluorescence intensity of ERK5,osteoprotegerin and receptor activator of nuclear factor-κB ligand in each group was detected by cell immunofluorescence staining,and cell proliferation was detected by EdU staining,respectively.The appropriate concentration and time of resveratrol intervention in MC3T3-E1 cells were determined by cell morphology observation and cell counting kit-8 assay. RESULTS AND CONCLUSION:The activation of ERK5 signaling protein could effectively promote the proliferation of MC3T3-E1 cells,up-regulate the osteoprotegerin/receptor activator of nuclear factor-κB ligand ratio.The appropriate concentration and time for resveratrol intervention in MC3T3-E1 cells was 5 μmol/L and 24 hours,respectively.Resveratrol could activate ERK5 signaling protein,thereby promoting osteoblast proliferation and up-regulating the osteoprotegerin/RANKL ratio.All these results indicate that resveratrol can promote the proliferation of MC3T3-E1 cells and up-regulate the osteoprotegerin/RANKL ratio by activating the ERK5 signaling protein.

BACKGROUND:Wolff's law points out that the lack of mechanical stress in the body will lead to the degradation of the microstructure of bone tissue,mass loss,and metabolic disorders,and eventually lead to osteoporosis,which suggests that mechanical stress plays an important role in the growth,reconstruction,and formation of bone tissue.At present,the relevant studies concerning mechanical stress on osteoblasts mainly focus on fluid shear force,but it is difficult to intervene in vivo.Meanwhile,some studies have found that compressive stress can also play a similar role in fluid shear force to a certain extent.Exploring the mode of action and influence of compressive stress on cells in vitro experiments can enrich the interaction relationship between mechanical stress and cells.It helps provide a theoretical basis for studies of metabolic bone diseases,including osteoporosis,and other diseases.OBJECTIVE:To review in vitro experiments,the application of compressive stress to cells,different biological behaviors caused by cells,the possible signaling pathways,and possible future applications.METHODS:We searched PubMed,Web of Science,CNKI,and WanFang databases from January 2000 to March 2024 to include all articles related to compressive stress on cells,including basic research and microscopic mechanism studies,using search terms"compressive stress,mechanical stress,hydrostatic pressure,cell"in Chinese and English.Finally,the 63 included articles were reviewed.RESULTS AND CONCLUSION:(1)There are various ways to apply compressive stress,and different experimental equipment has different ways of pressurizing cells,so it is necessary to further standardize the experimental equipment,standardize the pressurization unit,reduce the confounding factors,and make the reference and comparability between different experimental groups.(2)Compressive stress can cause changes in cell proliferation,differentiation,autophagy,apoptosis,migration,etc.,and the effect of compressive stress is time-or dose-dependent in most cases.(3)At present,most in vitro experimental studies have shown that compressive stress may mainly act on osteoblasts through MAPK signaling pathway and Wnt/β-catenin signaling pathway,causing osteoblasts to produce different responses.(4)The effect of compressive stress on different cells is not the same,and its possible biological effects need to be studied.(5)Further research on compressive stress is helpful to provide a theoretical basis for treatment in orthopedics,stomatology,tumors and other fields,and gentle disinfection using hydrostatic pressure is a promising disinfection method.

BACKGROUND:Wolff's law points out that the lack of mechanical stress in the body will lead to the degradation of the microstructure of bone tissue,mass loss,and metabolic disorders,and eventually lead to osteoporosis,which suggests that mechanical stress plays an important role in the growth,reconstruction,and formation of bone tissue.At present,the relevant studies concerning mechanical stress on osteoblasts mainly focus on fluid shear force,but it is difficult to intervene in vivo.Meanwhile,some studies have found that compressive stress can also play a similar role in fluid shear force to a certain extent.Exploring the mode of action and influence of compressive stress on cells in vitro experiments can enrich the interaction relationship between mechanical stress and cells.It helps provide a theoretical basis for studies of metabolic bone diseases,including osteoporosis,and other diseases.OBJECTIVE:To review in vitro experiments,the application of compressive stress to cells,different biological behaviors caused by cells,the possible signaling pathways,and possible future applications.METHODS:We searched PubMed,Web of Science,CNKI,and WanFang databases from January 2000 to March 2024 to include all articles related to compressive stress on cells,including basic research and microscopic mechanism studies,using search terms"compressive stress,mechanical stress,hydrostatic pressure,cell"in Chinese and English.Finally,the 63 included articles were reviewed.RESULTS AND CONCLUSION:(1)There are various ways to apply compressive stress,and different experimental equipment has different ways of pressurizing cells,so it is necessary to further standardize the experimental equipment,standardize the pressurization unit,reduce the confounding factors,and make the reference and comparability between different experimental groups.(2)Compressive stress can cause changes in cell proliferation,differentiation,autophagy,apoptosis,migration,etc.,and the effect of compressive stress is time-or dose-dependent in most cases.(3)At present,most in vitro experimental studies have shown that compressive stress may mainly act on osteoblasts through MAPK signaling pathway and Wnt/β-catenin signaling pathway,causing osteoblasts to produce different responses.(4)The effect of compressive stress on different cells is not the same,and its possible biological effects need to be studied.(5)Further research on compressive stress is helpful to provide a theoretical basis for treatment in orthopedics,stomatology,tumors and other fields,and gentle disinfection using hydrostatic pressure is a promising disinfection method.

Osteoporotic bone defect (OBD) is a serious bone defect resulting from the disruption of the bone structural integrity due to fractures in osteoporotic conditions. OBD not only leads to increased risk of fractures, delayed bone healing, functional loss, and chronic pain, but also reduces patients′ quality of life and even elevates the risk of death. Currently, OBD is primarily treated with systemic medications and local bone grafting. However, drug therapy is often associated with serious side effects, low bioavailability and poor bone targeting performance, while bone grafting is limited by high infection rate in donor areas, scarce bone source and severe immune rejection. Therefore, there is an urgent need for new bone repair materials to improve the bone microenvironment and stimulate bone regeneration. Bioactive molecules have shown great potential in modulating OBD treatment, but their application in organisms is hindered by their low bioavailability and short half-life. Hydrogels have emerged as an ideal vehicle to address these limitations by prolonging the retention time and half-life of bioactive molecules at the site of injury, reducing side effects and promoting cell adhesion under physiological conditions. All these advantages promote osteoblast proliferation and differentiation, providing a promising solution for OBD treatment. However, hydrogels still face challenges such as uncontrolled degradation rate, inadequate mechanical properties and poor osseointegration ability. To this end, the authors systematically elucidated the challenges of hydrogels in OBD treatment and proposed countermeasures, aiming to provide a reference for the research and clinical application of hydrogels.

Nonunion of osteoporotic vertebral fractures (OVF), predominantly affecting the elderly, can lead to intractable pain, vertebral collapse, progressive kyphotic deformity, and neurological impairment, significantly compromising patients′ quality of life. There exists considerable debate on diagnosis and management of OVF, encompassing key issues such as clinical diagnosis and staging criteria for nonunion, surgical indications and procedure selection, and postoperative rehabilitation planning. Currently, there lacks standardized clinical guideline and expert consensus on the diagnosis and management of OVF nonunion in China. To address this gap, Minimally Invasive Surgery Group of Chinese Orthopedic Association, Osteoporosis Committee of Chinese Association of Orthopedic Surgeons, Prevention and Rehabilitation Committee for Osteoporosis of Chinese Association of Rehabilitation Medicine and Minimally Invasive Orthopedic Surgery Branch of China Association for Geriatric Care jointly organized domestic experts in spinal surgery, endocrinology, and rehabilitation to formulate the Clinical guideline for the diagnosis and treatment for nonunion of osteoporotic vertebral fractures ( version 2025), based on existing literature and clinical experience and adhering to principles of scientific rigor and practicality. The guideline provided 13 evidence-based recommendations encompassing diagnosis and treatment of OVF nonunion, aiming to standardize its clinical management.

OBJECTIVE: To review the research progress of Schöttle's method in medial patellofemoral ligament reconstruction (MPFLR), and provide the latest knowledge and suggestions for surgical treatment. METHODS: The studies on Schöttle's method at home and abroad in recent years were extensively collected, then summarized the problems affecting the accuracy of Schöttle's method and the new ideas to improve the accuracy of localization. RESULTS: It's vital to accurately locate the femoral tunnel during MPFLR. Malposition of the femoral tunnel is the main cause of postoperative complications and surgical failure. Schöttle's method is the most well studied and most reproducible method for femoral tunnel localization, which is widely used as the "gold standard". However, there are still problems that affect the accuracy of Schöttle's method, including the impact of the internal/external rotation and varus/valgus of the knee on localization accuracy, unclear requirements for X-ray imaging and anatomical landmark reference line drawing standards, no suitable for patients with anatomical variations, and lack of further research on pediatric patients. In recent years, some new ideas are proposed to improve the Schöttle's method to improve the localization accuracy. CONCLUSION Future research should combine new technologies such as three-dimensional (3D) printing and intraoperative navigation to develop personalized and intelligent Schöttle's method, further improving their localization accuracy.
Humans ; Femur/surgery* ; Plastic Surgery Procedures/methods* ; Patellofemoral Joint/surgery* ; Patellar Ligament/surgery* ; Postoperative Complications ; Knee Joint/surgery* ; Ligaments, Articular/surgery* ; Tomography, X-Ray Computed/methods*

BACKGROUND:Fluid shear stress plays an important role in osteoblast proliferation and apoptosis.However,whether Caveolin-1 is involved in the process of fluid shear stress-induced proliferation and apoptosis in osteoblasts is unknown. OBJECTIVE:To explore the role of Caveolin-1 in fluid shear stress-regulated osteoblast proliferation and apoptosis. METHODS:The MC3T3-E1 osteoblasts in good growth status were selected and loaded with fluid shear stress at an intensity of 1.2 Pa for different times(0,30,60,90 minutes).The expression of Caveolin-1 protein was observed and conditions with a time of 60 minutes were screened for the experiment.MC3T3-E1 cells were divided into control group,fluid shear stress group,fluid shear stress+pcDNA 3.1 group(control),fluid shear stress+pcDNA Cav-1 group(plasmid overexpression),and intervened with fluid shear stress and overexpression of Cav-1,respectively.The expression of molecules related to proliferation and apoptosis in MC3T3-E1 cells was detected by qRT-PCR and western blot.In addition,the proliferative activity of MC3T3-E1 cells was detected by cell counting kit-8 and EdU assay;and cell apoptosis was detected by Hoechst 33258 and flow cytometry. RESULTS AND CONCLUSION:The expression of Caveolin-1 in MC3T3-E1 cells was significantly down-regulated after loading fluid shear stress,and the expression level was lowest after 60 minutes.Overexpression of Caveolin-1 attenuated the proliferation-promoting and apoptosis-suppressing effects of fluid shear stress in MC3T3-E1 cells.In conclusion,Caveolin-1 has a vital role in fluid shear stress-regulated osteoblast proliferation and apoptosis,which may offer a potential therapeutic strategy for osteoporosis.