Postoperative infection of internal fixation of closed fractures the lower limbs in adults represents a devastating complication, characterized by diagnostic challenges, prolonged treatment duration and high disability rates. Current management of these infections faces multiple challenges, such as difficulties in early accurate diagnosis, and various controversies about the treatment plan, leading to poor overall diagnosis and treatment results. To address these issues, based on evidence-based medicine and principles with emphasis on scientific rigor, clinical applicability and innovation, the Trauma Branch of the Chinese Medical Association, Orthopedic Branch of the Chinese Medical Doctor Association, Orthopedics Branch of the Chinese Medical Association, and Trauma Orthopedics and Polytrauma Group of the Resuscitation and Emergency Committee of the Chinese Medical Doctor Association have collaboratively organized a panel of relevant experts to develop the Guideline for diagnosis and treatment of infection after internal fixation of closed lower limb fractures in adults ( version 2025). The guideline proposed 10 recommendations, aiming to provide a foundation for standardized diagnosis and treatment of postoperative infection in adults with closed lower limb fractures.

BACKGROUND:The asymmetrical biomechanical environment of adolescent idiopathic scoliosis can lead to further wedge deformation of the vertebral body,which may affect cardiopulmonary function and compress nerves in severe cases.Adolescent idiopathic scoliosis with different degrees of scoliosis should be treated with exercise,bracing,and surgery.However,the mechanical mechanism of selecting an orthopedic approach remains unclear due to the individual variability of patients.OBJECTIVE:To investigate the biomechanical mechanism of different orthopedic modalities for the treatment of adolescent idiopathic scoliosis to provide a basis for clinical selection of treatment modalities based on the spine model of adolescent idiopathic scoliosis patients.METHODS:Based on the CT images of an adolescent idiopathic scoliosis patient,a scoliosis model(C7-L5)was reconstructed in Mimics software in three dimensions,and lateral thrust force was applied at the T8/T9 thorax and vertical distraction force was applied over the C7 vertebra with the magnitude of 20,40,60,80,100,and 120 N.The intervertebral disc stress and vertebral displacement in concave and convex sides,and Cobb angle of the spine were analyzed under two orthopedic modalities.RESULTS AND CONCLUSION:(1)With lateral thrust,there was no significant change in the C7T1-T7T8 intervertebral disc.The concave and convex stress of T7T8-L4L5 segment decreased first and then increased with the increase of lateral thrust force.The correction effect of lateral thrust on the segment near T8T9 was obvious and weakened with the extension of the segment to the cephalic and caudal ends.At 120 N of lateral thrust,the thoracic Cobb angle changed from 53.2° to 32.5° and the lumbar Cobb angle changed from 50.2° to 43.9°.(2)With the vertical distraction,the thoracic intervertebral disc stresses first decreased and then increased,and all the lumbar disc stresses decreased.The C7 displacement was the most obvious,and the correction effect gradually diminished with the segment extended to the caudal end.At a vertical distraction force of 120 N,the thoracic Cobb angle changed from 53.2° to 39.4° and the lumbar Cobb angle changed from 50.2° to 47.6°.(3)It is concluded that both orthopedic modalities provide improvement in the degree of scoliosis,with the thoracic correction being greater than the lumbar correction.Also,the asymmetric stress distribution on the concave and convex sides is improved,which contributes to normal bone growth.A vertical distraction approach is appropriate for larger Cobb angles,and a lateral thrust approach is appropriate for smaller Cobb angles.The results of this study help to understand the mechanism of spinal orthosis and provide a theoretical basis for the choice of orthopedic approach.

Melanoma is characterized by high malignancy, ranking the third among skin malignancies, and is associated with lack of specific treatment options and poor prognosis. Therefore, the development of effective therapies for melanoma is imperative. A critical challenge in addressing subcutaneous disease lies in overcoming the skin barrier. In this study, we engineered a microneedle (MN) system that integrates chemotherapy, photothermal therapy (PTT), and targeted therapy to enhance anti-tumor efficacy while effectively penetrating the skin barrier. In vitro studies have demonstrated that the MN drug delivery system (DDS) can effectively penetrate the stratum corneum of the skin, deliver therapeutics to subcutaneous tumor sites, and establish a drug reservoir at these locations to exert anti-tumor effects. Cellular experiments indicated that the engineered PTT chemotherapy-targeted MNs can be internalized by tumor cells, exhibiting enhanced cytotoxicity against them. In vivo pharmacological investigations revealed that the combination of PTT and chemotherapy delivered via this MN DDS produced synergistic anti-tumor effects, achieving a tumor inhibition rate of up to 98.15%. This in situ DDS minimizes involvement with other organs, significantly reducing chemotherapy-related side effects. In summary, the PTT chemotherapy-targeted MNs developed in this study demonstrate promising application potential by enhancing anti-tumor efficacy while minimizing adverse effects.

Objective:Papillary thyroid carcinoma with a maximum tumor diameter of ≤1 cm was defined as papillary thyroid carcinoma (PTC). To explore the clinical risk factors of central lymph node metastasis (CLNM) in PTC at different locations.Methods:The clinical and pathological data of 1383 cases with solitary PTC in Hangzhou First People’s Hospital were retrospectively analyzed, and they were divided into isthmus group (175 cases), near-isthmus group (95 cases) and lateral lobe group (1113 cases) according to their tumor location. Univariate and multivariate analyses were used to analyze the relationship between gender, age, tumor maximum diameter, Hashimoto’s thyroiditis (HT) and CLNM, and the threshold for the occurrence of CLNM in each group of age and tumor maximum diameter was determined by the area under the receiver operating characteristic (ROC) .Results:The proportion of CLNM in the isthmus group, near-isthmus group and the lateral lobe group were 39.4% (69/175), 35.8% (34/95) and 29.6% (329/1113), respectively ( χ2=7.84, P=0.020). The intra-group comparison showed that there were statistical differences between the isthmus group and the lateral lobe group ( χ2=6.90, P=0.011), and there were no statistical differences between the isthmus group and near-isthmus group ( χ2=0.35, P=0.601), and near-isthmus group and the lateral leaf group ( χ2=1.62, P=0.313). Univariate and multivariate analysis showed that male ( OR: 3.697) and age < 38.5 years ( OR: 4.727) were independent risk factors for CLNM in PTC in the Isthmus Group, while male ( OR: 2.193), without HT ( OR: 1.702), tumor maximum diameter > 6.5 mm ( OR: 2.535) and age < 45.5 years ( OR: 3.030) were independent risk factors for CLNM in PTC in the lateral lobe group. Conclusions:Male sex and age are independent risk factors for CLNM in isthmus and lateral lobe PTC, and uncomplicated HT and tumor maximum diameter are also independent risk factors for CLNM in lateral lobe PTC. The incidence of CLNM in PTC in the isthmus, near-isthmus and lateral lobes decreased sequentially, and PTC in the near isthmus can not be simply regarded as the isthmus or lateral lobe PTC, and the lymph nodes in the central area should be fully evaluated before surgery to provide individualized treatment.

Objective:Papillary thyroid carcinoma with a maximum tumor diameter of ≤1 cm was defined as papillary thyroid carcinoma (PTC). To explore the clinical risk factors of central lymph node metastasis (CLNM) in PTC at different locations.Methods:The clinical and pathological data of 1383 cases with solitary PTC in Hangzhou First People’s Hospital were retrospectively analyzed, and they were divided into isthmus group (175 cases), near-isthmus group (95 cases) and lateral lobe group (1113 cases) according to their tumor location. Univariate and multivariate analyses were used to analyze the relationship between gender, age, tumor maximum diameter, Hashimoto’s thyroiditis (HT) and CLNM, and the threshold for the occurrence of CLNM in each group of age and tumor maximum diameter was determined by the area under the receiver operating characteristic (ROC) .Results:The proportion of CLNM in the isthmus group, near-isthmus group and the lateral lobe group were 39.4% (69/175), 35.8% (34/95) and 29.6% (329/1113), respectively ( χ2=7.84, P=0.020). The intra-group comparison showed that there were statistical differences between the isthmus group and the lateral lobe group ( χ2=6.90, P=0.011), and there were no statistical differences between the isthmus group and near-isthmus group ( χ2=0.35, P=0.601), and near-isthmus group and the lateral leaf group ( χ2=1.62, P=0.313). Univariate and multivariate analysis showed that male ( OR: 3.697) and age < 38.5 years ( OR: 4.727) were independent risk factors for CLNM in PTC in the Isthmus Group, while male ( OR: 2.193), without HT ( OR: 1.702), tumor maximum diameter > 6.5 mm ( OR: 2.535) and age < 45.5 years ( OR: 3.030) were independent risk factors for CLNM in PTC in the lateral lobe group. Conclusions:Male sex and age are independent risk factors for CLNM in isthmus and lateral lobe PTC, and uncomplicated HT and tumor maximum diameter are also independent risk factors for CLNM in lateral lobe PTC. The incidence of CLNM in PTC in the isthmus, near-isthmus and lateral lobes decreased sequentially, and PTC in the near isthmus can not be simply regarded as the isthmus or lateral lobe PTC, and the lymph nodes in the central area should be fully evaluated before surgery to provide individualized treatment.

BACKGROUND:The asymmetrical biomechanical environment of adolescent idiopathic scoliosis can lead to further wedge deformation of the vertebral body,which may affect cardiopulmonary function and compress nerves in severe cases.Adolescent idiopathic scoliosis with different degrees of scoliosis should be treated with exercise,bracing,and surgery.However,the mechanical mechanism of selecting an orthopedic approach remains unclear due to the individual variability of patients.OBJECTIVE:To investigate the biomechanical mechanism of different orthopedic modalities for the treatment of adolescent idiopathic scoliosis to provide a basis for clinical selection of treatment modalities based on the spine model of adolescent idiopathic scoliosis patients.METHODS:Based on the CT images of an adolescent idiopathic scoliosis patient,a scoliosis model(C7-L5)was reconstructed in Mimics software in three dimensions,and lateral thrust force was applied at the T8/T9 thorax and vertical distraction force was applied over the C7 vertebra with the magnitude of 20,40,60,80,100,and 120 N.The intervertebral disc stress and vertebral displacement in concave and convex sides,and Cobb angle of the spine were analyzed under two orthopedic modalities.RESULTS AND CONCLUSION:(1)With lateral thrust,there was no significant change in the C7T1-T7T8 intervertebral disc.The concave and convex stress of T7T8-L4L5 segment decreased first and then increased with the increase of lateral thrust force.The correction effect of lateral thrust on the segment near T8T9 was obvious and weakened with the extension of the segment to the cephalic and caudal ends.At 120 N of lateral thrust,the thoracic Cobb angle changed from 53.2° to 32.5° and the lumbar Cobb angle changed from 50.2° to 43.9°.(2)With the vertical distraction,the thoracic intervertebral disc stresses first decreased and then increased,and all the lumbar disc stresses decreased.The C7 displacement was the most obvious,and the correction effect gradually diminished with the segment extended to the caudal end.At a vertical distraction force of 120 N,the thoracic Cobb angle changed from 53.2° to 39.4° and the lumbar Cobb angle changed from 50.2° to 47.6°.(3)It is concluded that both orthopedic modalities provide improvement in the degree of scoliosis,with the thoracic correction being greater than the lumbar correction.Also,the asymmetric stress distribution on the concave and convex sides is improved,which contributes to normal bone growth.A vertical distraction approach is appropriate for larger Cobb angles,and a lateral thrust approach is appropriate for smaller Cobb angles.The results of this study help to understand the mechanism of spinal orthosis and provide a theoretical basis for the choice of orthopedic approach.

Postoperative infection of internal fixation of closed fractures the lower limbs in adults represents a devastating complication, characterized by diagnostic challenges, prolonged treatment duration and high disability rates. Current management of these infections faces multiple challenges, such as difficulties in early accurate diagnosis, and various controversies about the treatment plan, leading to poor overall diagnosis and treatment results. To address these issues, based on evidence-based medicine and principles with emphasis on scientific rigor, clinical applicability and innovation, the Trauma Branch of the Chinese Medical Association, Orthopedic Branch of the Chinese Medical Doctor Association, Orthopedics Branch of the Chinese Medical Association, and Trauma Orthopedics and Polytrauma Group of the Resuscitation and Emergency Committee of the Chinese Medical Doctor Association have collaboratively organized a panel of relevant experts to develop the Guideline for diagnosis and treatment of infection after internal fixation of closed lower limb fractures in adults ( version 2025). The guideline proposed 10 recommendations, aiming to provide a foundation for standardized diagnosis and treatment of postoperative infection in adults with closed lower limb fractures.

Objective:To explore the effects of posterior malleolar fracture fixation on the rotational stability of the ankle joint.Methods:A total of 20 fresh cadaveric specimens of lower limbs were anatomized to measure the area of attachment of the posterior inferior tibiofibular ligament and transverse ligament complex to the posterior surface of the tibia. One healthy volunteer was selected to construct a finite element model for the intact tibiofibular and ankle joints and finite element models for posterior malleolar fracture with different posterior projection areas. A load of 600 N was vertically applied to the inferior calcaneus along the tibial mechanical axis. The contact area and maximum Von Mises stress of the distal tibial articular surface were analyzed to verify the validity of the model for the intact tibiofibular and ankle joints. In the finite element models for the posterior malleolar fracture (S, 1/2S, 1/4S, 1/8S and 1/16S model groups, with S standing for the complete projection area of the ligament complex on the posterior surface of the tibia), the width increase in the tibiofibular clear space was measured when a vertical load of 600 N and external rotation load of 5 N·m were applied to the ankle joint after the reduction and fixation of posterior malleolar fracture. The cutoff value of the posterior projection area of posterior malleolar fracture that could maintain the rotational stability of the ankle joint was assessed.Results:The measurement results of the cadaveric specimens showed that the area of attachment of the posterior inferior tibiofibular ligament and transverse ligament complex to the posterior surface of the tibia was relatively large. It was attached to the posterolateral area of the distal tibia with the highest point located at (45.2±5.6)mm from the articular surface. With the increase in the distance from the joint line, the width of the posterior attachment area of the ligament complex was decreased. Results of the finite element analysis showed that in the finite element model for the intact tibiofibular and ankle joints, the tibiotalar joint contact area was 324.02 mm 2 and the maximum Von Mises stress was 4.495 1 MPa with a vertical load of 600 N. In the finite element models for the posterior malleolar fracture, the distal tibiofibular clear spaces of the S, 1/2S, 1/4S and 1/8S model groups increased by less than 2 mm following loading, while it was increased by 3.445 8 mm in the 1/16S model group. The cutoff value of the posterior tibial projection area that could maintain the rotational stability of the ankle joint was 1/8S. Conclusions:The attachment area of the posterior inferior tibiofibular ligament and transverse ligament complex to the posterior surface of the tibia is large. Both the axial stability and rotational stability of the ankle joint should be considered in the treatment selection for posterior malleolar fracture. Simple posterior malleolar fixation is recommended to restore the rotational stability and axial stability of the ankle joint when tibiofibular syndesmosis is unstable and the cutoff value is larger than or equal to 1/8, while tibiofibular syndesmosis screws must be implanted when tibiofibular syndesmosis is unstable and the cutoff value is less than 1/8.

BACKGROUND:Ankylosing spondylitis is a chronic inflammatory disease with chronic rheumatic immunity.Soft tissue ossification and fusion and spinal stiffness can cause biomechanical changes. OBJECTIVE:To reconstruct the lumbar-sacral intervertebral disc in ankylosing spondylitis patients with lumbar kyphosis by finite element analysis,and to study the range of motion of each segment of T11-S1 and the biomechanical characteristics of annulus fibrosus and nucleus pulposus. METHODS:The imaging data were obtained from an ankylosing spondylitis patient with lumbar kyphosis.The original CT image data of continuously scanned spine were imported into Mimics 21.0 in DICOM format,and T11-S1 was reconstructed respectively.The established model was imported into 3-Matic software in the format of"Stl"to reconstruct the intervertebral disc,and the fibrous intervertebral disc model was obtained.The improved model was further imported into Hypermesh software,and the vertebra,nucleus pulposus,annulus fibrosus and ligament were mesh-divided.After the material properties were given,the model was imported into ABAQUS software to observe the range of motion of each vertebral body in seven different working conditions of T11-S1,and analyze the biomechanical characteristics of each segment of annulus fibrosus and nucleus pulposus. RESULTS AND CONCLUSION:(1)The range of motion of L1 vertebrae was higher than that of other vertebrae under six different working conditions:extension,forward flexion,rotation(left and right),and lateral flexion(left and right).The maximum range of motion was 2.18° during L1 vertebral flexion,and the minimum range of motion was 0.12° during L5 vertebral extension.(2)The annular fiber flexion at L2-L3 segments was greater than the extension(P<0.05),and the annular fiber flexion at L3-L4 and L4-L5 segments was less than the extension(P<0.05).The left rotation of L1-L2 annular fibers was greater than the right rotation(P<0.05).The left flexion of the annulus was greater than the right flexion in L1-L2,L2-L3,L3-L4,L4-L5 and L5-S1 segments(P<0.05).(3)The nucleus pulposus stresses of T11-L12,L1-L2,L2-L3,L3-L4 and L4-L5 segments in forward flexion were greater than in extension(P<0.05).The left rotation of T12-L1 and L3-L4 segments was smaller than the right rotation(P<0.05),and that of T11-T12,L1-L2,and L2-L3 segments was larger than the right rotation(P<0.05).The left flexion was larger than the right flexion in the T11-S1 segment.(4)It is concluded that in ankylosing spondylitis patients with lumbar kyphosis,the minimum range of motion of the vertebral body is located at the L5 vertebral body in extension.To prevent fractures,it is recommended to avoid exercise in the extension position.During the onset of lumbar kyphosis in patients with ankylosing spondylitis,the maximum stress of the annulus fibrosus and nucleus pulposus is located in the L1-L2 segment,which is fixed and will not alter with the change of body position.The late surgical treatment and correction of deformity should focus on releasing the pressure of the annulus fibrosus and nucleus pulposus in this segment to avoid the rupture of the annulus fibrosus and the injury of the nucleus pulposus.

BACKGROUND:Ankylosing spondylitis is a progressive inflammation of spinal stiffness deformity caused by tissue ossification and fibrosis.The posture of ankylosing spondylitis patients is abnormal and their activities are limited that minor injuries can lead to thoracolumbar fractures.Traditional medical image observation limits doctors'preoperative decision planning and postoperative disease prevention for ankylosing spondylitis treatment. OBJECTIVE:Based on the spinal model of ankylosing spondylitis patients before and after posterior spinal cancellous ossification osteotomy("Y"osteotomy for short),to explore the biomechanical changes of"Y"osteotomy and fixation in the treatment of ankylosing spondylitis. METHODS:Based on the preoperative and postoperative CT images of an ankylosing spondylitis patient who went to the Second Affiliated Hospital of Inner Mongolia Medical University,a three-dimensional spine model(T11-S1)before and after"Y"osteotomy(L3 osteotomy)was reconstructed in Mimics 19.0 software.A 7.5 Nm torque was applied to the top of T11 vertebral body to simulate the movement of the spine under six conditions:flexion,extension,left bending,right bending,left rotation and right rotation.Finally,the range of motion of each vertebral body,the stress of each intervertebral disc,and the stress of the screw rod system were simulated. RESULTS AND CONCLUSION:(1)After"Y"type osteotomy and posterior fixation,the range of motion of all vertebrae in the spine decreased,and the loss rate of upper vertebrae was large(L1:77.95%).(2)The maximum stress of the spinal intervertebral disc before operation occurred at the L1-L2 segment(0.55 MPa),and the maximum stress of the spinal intervertebral disc after operation occurred at the T11-T12 segment(0.50 MPa),and the stress of intervertebral disc below T12 was far less than that before operation.(3)The maximum stress of the screw rod system(166.67 MPa)occurred in the upper and middle segments of the rod body and the root of the pedicle screw.(4)In conclusion,the"Y"type posterior fixation operation enhances the stability of the spine and reduces the range of motion of the spine.The vertebral body decompression of the fixed segment is great and the stress-shielding phenomenon of the lower vertebral body is significant.The stiffness of the rod body and the stress concentration area of the pedicle screw should be strengthened to avoid the fracture of the rod caused by stress fatigue.