Three-dimensional finite element analysis of mechanical stability of double screw internal fixation for talar neck fracture / 中华创伤杂志

Objective The three-dimensional finite element analysis was done to analyze the mechanical stability of double screw internal fixation for talus neck fracture,the methods with different approaches and different placement methods as well as the optimal biomechanical environment of fracture section were discussed so as to provide reliable mechanical arguments for the selection of clinical internal fixators.Methods The acquired male adult ankle CT data were imported into Mimics for 3D reconstruction of the ankle joint model.After the model was fitted with the surface by Geomagic software,the model was imported into Solidwork software to establish the talus neck fracture model and the corresponding screw.The fixtures were assembled with the anterior-posterior parallel double screw,the anterior-posterior cross-double screw,the posterior-anterior parallel double screw,and the posterioranterior cross-double screw,respectively.The model data were imported to Abaqus 6.14 for analysis and calculation,followed by the meshing pretreatment using software Hypermesh 13.0.The Von Mises stress distribution of the lag screw and displacement of the fracture end were observed under different fixation modes.Results In the displacement and stress cloud diagrams of the fracture ends of the four groups,the displacement peaks of the fractures of the anterior to posterior double-screw parallel and cross-fixed groups were 0.399 3 mm and 0.418 6 mm,and the peak pressures were 7.721 MPa and 8.124 MPa,respectively.The displacement peaks of posterior to anterior double-screw parallel and cross-groups were 0.418 3 mm and 0.418 5 mm,the fracture end peak pressures were 4.848 MPa and 5.692 MPa,respectively.In the screw stress cloud diagram of the four internal fixation modes,the Von Mises stress peaks of the anterior-posterior parallel screw group and cross-screw group were 45.11 MPa and 50.18 MPa,and those of the posterior-anterior parallel screw group and cross-screw group were 30.65 MPa and 37.68 MPa,respectively.Conclusion In the posterior-anterior parallel screw fixation,the fracture end has the lowest stress,and the screw has dispersive stress and the stress peak is the lowest,which is superior to other three groups.Therefore,the posterior-anterior screw is better than anterior-posterior fixation,and the parallel fixation is better than cross fixation.

Review of high-resolution peripheral quantitative computed tomography for the assessment of bone microstructure and strength / 生物医学工程学杂志

Trabecular microstructure is an important factor in determining bone strength and physiological function. Normal X-ray and computed tomography (CT) cannot accurately reflect the microstructure of trabecular bone. High-resolution peripheral quantitative computed tomography (HR-pQCT) is a new imaging technique in recent years. It can qualitatively and quantitatively measure the three-dimensional microstructure and volume bone mineral density of trabecular bone . It has high precision and relative low dose of radiation. This new imaging tool is helpful for us to understand the trabecular microstructure more deeply. The finite element analysis of HR-pQCT data can be used to predict the bone strength accurately. We can assess the risk of osteoporosis and fracture with three-dimensional reconstructed images and trabecular microstructure parameters. In this review, we summarize the technical flow, data parameters and clinical application of HR-pQCT in order to provide some reference for the popularization and extensive application of HR-pQCT.

Research progress of treating osteoporosis with Longspur epimedium / 中国中西医结合急救杂志

Osteoporosis is a systemic metabolic osteopathy characterized by low bone mineral density, leading to an increased risk of bone fractures. The study on the treatment of osteoporosis is mostly a research hotspot, and traditional Chinese medicine in treatment of this disease has its distinctive ascendancy. A large quantity of research indicates that the effect of Longspur epimeium (LE) for treatment of osteoporosis is definite. In this article, the authors summarized the drug components, the results of experimental research and clinical trial of LE for treatment of osteoporosis in recent years.

Biomechanical comparison of Gamma3 and InterTan nails for stable and unstable intertrochanteric fractures / 中华创伤骨科杂志

Objective To compare the biomechanical properties of Gamma3 and InterTan nails in the fixation of femoral intertrochanteric fractures. Methods Twelve synthetic femora of 4th generation were randomized into 4 equal groups ( n=3 ) for assessment of the 2 constructs of fracture fixation ( Gamma3 versus InterTan nails ) . Groups A and B were made into models of stable femoral intertrochanteric fracture (AO/OTA type 31-A1. 1) and groups C and D into unstable ones(AO/OTA type 31-A2. 3) . The biomechanical properties of Gamma3 and InterTan nails in the 4 models were tested and compared. Results For stable fracture models, the fracture gap movement increased with the increasing axial load and the torque increased with the increasing torsion angle. There were significant differences between groups A and B in fracture gap movement and torque ( P 0. 05 ) . For unstable fracture models, there were no significant differences between groups C and D in fracture gap movement when the axial loads were 500 N, 600 N or 700 N ( P > 0. 05 ) , but there was a significant difference between the 2 groups when the axial load was larger than 800 N ( P <0. 05 ) . With the increasing torsion angle, the torque increased in groups C and D. There was a significant difference between the 2 groups in the torque at the same torsion angle ( P <0. 05 ) . There were a significant difference between groups C and D in failure load ( 2, 781. 5 ± 600. 6 N versus 3, 150. 5 ± 633. 8 N ) ( P=0. 007 ) . Conclusions For stable femoral intertrochanteric fractures, InterTan and Gamma3 nails may exhibit similar biomechanical properties. For unstable femoral intertrochanteric fractures, InterTan nails may provide obviously better biomechanical stability than Gamma3 nails.

Comparisons between perioperative continuous femoral nerve block and patient controlled analgesia for analgesia in primary total knee arthroplasty: a Meta-analysis / 中华创伤杂志

Objective To evaluate the efficacy and safety of continuous femoral nerve block (CFNB) versus patient controlled analgesia (PCA) for analgesia in primary total knee arthroplasty (TKA) through a Meta-analysis.Methods All randomized controlled trials (RCTs) which compared about the efficacy and safety of CFNB versus PCA for analgesia in primary TKA,were searched from Cochrane Library,Embase,PubMed,CBM,VIP,Wang Fang database and CNKI.At the same time,conference papers were identified manually.A quality assessment of the included literature was evaluated by Cochrane system evaluation manually.Revman 5.3 software was used for the Meta-analysis to compare visual analogue scale (VAS),hospital for special surgery knee score (HSS),western Ontario and McMaster university of orthopedic index (WOMAC),patient satisfactory degree,and incidences of complications (nausea,vomit,dizziness,somnolence,itch of skin,etc).Results Twenty-four RCTs involving 1896 patients were identified including CFNB (946 cases) and PCA (950 cases) application of TKA.The pooled results illustrated that CFNB could reduce VAS in rest (MD =-1.28,95％ CI-1.56,-1.00,P ＜ 0.05) and VAS in movement (MD =-0.98,95％ CI-1.38,-0.58,P ＜ 0.05),increase HSS (MD =2.13,95％ CI 0.12,4.14,P ＜0.05),reduce WOMAC(MD =-0.97,95％ CI-1.83,-0.11,P ＜ 0.05),increase patient satisfactory degree (RR =1.27,95 ％ CI 1.10,1.46,P ＜ 0.05) and at the same time reduce the incidences of nausea,vomit,dizziness,somnolence and itch of skin (RR =0.32,95％CI0.24,0.43,P＜0.05).Conclusion Compared with PCA,CFNB analgesia can reduce VAS,WOMAC score,improve the postoperative HSS and patient satisfaction degree,and decrease the risk of complications.

Comparisons between perioperative continuous femoral nerve block and patient controlled analgesia for analgesia in primary total knee arthroplasty: a Meta-analysis / 中华创伤杂志

Objective To evaluate the efficacy and safety of continuous femoral nerve block (CFNB) versus patient controlled analgesia (PCA) for analgesia in primary total knee arthroplasty (TKA) through a Meta-analysis.Methods All randomized controlled trials (RCTs) which compared about the efficacy and safety of CFNB versus PCA for analgesia in primary TKA,were searched from Cochrane Library,Embase,PubMed,CBM,VIP,Wang Fang database and CNKI.At the same time,conference papers were identified manually.A quality assessment of the included literature was evaluated by Cochrane system evaluation manually.Revman 5.3 software was used for the Meta-analysis to compare visual analogue scale (VAS),hospital for special surgery knee score (HSS),western Ontario and McMaster university of orthopedic index (WOMAC),patient satisfactory degree,and incidences of complications (nausea,vomit,dizziness,somnolence,itch of skin,etc).Results Twenty-four RCTs involving 1896 patients were identified including CFNB (946 cases) and PCA (950 cases) application of TKA.The pooled results illustrated that CFNB could reduce VAS in rest (MD =-1.28,95％ CI-1.56,-1.00,P ＜ 0.05) and VAS in movement (MD =-0.98,95％ CI-1.38,-0.58,P ＜ 0.05),increase HSS (MD =2.13,95％ CI 0.12,4.14,P ＜0.05),reduce WOMAC(MD =-0.97,95％ CI-1.83,-0.11,P ＜ 0.05),increase patient satisfactory degree (RR =1.27,95 ％ CI 1.10,1.46,P ＜ 0.05) and at the same time reduce the incidences of nausea,vomit,dizziness,somnolence and itch of skin (RR =0.32,95％CI0.24,0.43,P＜0.05).Conclusion Compared with PCA,CFNB analgesia can reduce VAS,WOMAC score,improve the postoperative HSS and patient satisfaction degree,and decrease the risk of complications.