BACKGROUND:The C1 type fracture of the distal radius is an intraarticular unstable fracture,which is difficult to treat.At present,there are few clinical studies about the comparison of the biomechanical differences of different internal fixation plates for distal radius fractures under different loading conditions,and there are still controversies in the selection of internal fixation plates.OBJECTIVE:To compare the biomechanical properties of different internal fixation plates for C1 type fractures of distal radius using a finite element analysis method.METHODS:The distal radius model of a healthy female volunteer was used,and the files were sequentially imported into Mimics 21.0,Geomagic Wrap 2017,and Solid Works 2021 for processing.The C1 type fracture of the distal radius was modeled.According to the plate data provided by the manufacturer,the volar oblique T-locking plate,volar fixed-angle anatomical plate,volar variable-angle locking plate and screws three-dimensional model were created and assembled with the fracture model.The material properties were given in ANSYS 19.0 to set up the relationship of interaction between the contact surfaces,and to define the loads and boundary conditions.Four load cases,including compression,dorsal flexion,palmar flexion and torsion,were applied to compare the biomechanical properties.RESULTS AND CONCLUSION:(1)In the three groups of internal fixation models,the overall displacement of the internal fixation model was mainly concentrated on the articular surface of the distal radius under four load conditions.The maximum displacement of the model under the dorsal,palmar and torsion load conditions was 2-6 times that of the displacement under the axial load,indicating that the internal fixation system was the most stable under the axial load condition.(2)The stress on the internal fixation was much greater than the stress on the bone fracture fragments.The stress of the internal fixation was mainly concentrated in the area that near to the fracture end of the bone plate,among which the stress distribution of the volar fixed-angle anatomical plate,volar variable-angle locking plate was relatively uniform,and the stress concentration of the oblique T-locking plate was the most obvious.(3)Under compressive and torsional loads,the stress of the fracture fragments was mainly concentrated in the area that around the screw holes.Under dorsal and palmar flexion,it gradually expanded from the distal end to the proximal radius.Under the same load condition,the stress of the fracture block in the oblique T-locking plate fixation state was the highest,and the peak stress of the fracture fragments in the volar variable-angle locking plate fixation system was the lowest.The difference between the peak stress of the bone fracture fragments in the fixed state of the volar fixed-angle anatomical plate and the volar variable-angle locking plate was only in the range of 0.2-6.0 MPa.(4)It is indicated that compared with the oblique T-locking plate and the volar fixed-angle anatomical plate,the volar variable-angle locking plate has more uniform stress distribution,less displacement of articular surface,and the best stability in the internal fixation in the C1 type fracture of the distal radius.

BACKGROUND:The phosphatidylinositol 3-kinase/protein kinase(PI3K/AKT)signaling pathway plays a pivotal role in regulating osteoclast activation,which is essential for maintaining bone homeostasis.Bone destruction in osteoarticular tuberculosis is caused by aberrant osteoclastogenesis induced by Mycobacterium tuberculosis infection.However,the role of the PI3K signaling pathway in Mycobacterium tuberculosis-induced aberrant osteoclastogenesis remains unclear. OBJECTIVE:To investigate the effects and mechanisms of the PI3K/AKT signaling pathway inhibitor BYL-719 on aberrant osteoclastogenesis induced by Mycobacterium tuberculosis. METHODS:RAW264.7 cells were infected with bovine Mycobacterium tuberculosis bacillus calmette-cuerin vaccine,and Ag85B was used for cellular immunofluorescence staining.The cell counting kit-8 assay was employed to determine the safe concentration of BYL-719.There were four groups in the experiment:blank control group,BYL-719 group,BCG group,and BCG+BYL-719 group.Under the induction of receptor activator of nuclear factor kappa-B ligand,the effects of BYL-719 on post-infection osteoclast differentiation and fusion were explored through tartrate-resistant acid phosphatase staining and phalloidin staining.RT-PCR and western blot were used to detect the expression of osteoclast-related genes and proteins,and further investigate the mechanism of action. RESULTS AND CONCLUSION:Immunofluorescence staining showed that RAW264.7 cells phagocytosed Mycobacterium tuberculosis.Cell counting kit-8 data indicated that 40 nmol/L BYL-719 was non-toxic to cells.Tartrate-resistant acid phosphatase staining and phalloidin staining showed that BYL-719 inhibited the generation and fusion ability of osteoclasts following infection.RT-PCR and western blot results also indicated that BYL-719 suppressed the upregulation of osteoclast-specific genes(including c-Fos,NFATc1,matrix metalloproteinase 9,and CtsK)induced by Mycobacterium tuberculosis infection(P<0.05).Western blot and immunofluorescence staining revealed that BYL-719 inhibited excessive osteoclast differentiation induced by Mycobacterium tuberculosis by downregulating the expression of IκBα-p65.To conclude,BYL-719 inhibits aberrant osteoclastogenesis induced by Mycobacterium tuberculosis through the downregulation of IκBα/p65.Therefore,the IκBα/p65 signaling pathway is a potential therapeutic target for osteoarticular tuberculosis,and BYL-719 holds potential value for the preventing and amelioration of bone destruction in osteoarticular tuberculosis.BYL-719 has the potential to prevent and ameliorate bone destruction in osteoarticular tuberculosis.

BACKGROUND:The C1 type fracture of the distal radius is an intraarticular unstable fracture,which is difficult to treat.At present,there are few clinical studies about the comparison of the biomechanical differences of different internal fixation plates for distal radius fractures under different loading conditions,and there are still controversies in the selection of internal fixation plates.OBJECTIVE:To compare the biomechanical properties of different internal fixation plates for C1 type fractures of distal radius using a finite element analysis method.METHODS:The distal radius model of a healthy female volunteer was used,and the files were sequentially imported into Mimics 21.0,Geomagic Wrap 2017,and Solid Works 2021 for processing.The C1 type fracture of the distal radius was modeled.According to the plate data provided by the manufacturer,the volar oblique T-locking plate,volar fixed-angle anatomical plate,volar variable-angle locking plate and screws three-dimensional model were created and assembled with the fracture model.The material properties were given in ANSYS 19.0 to set up the relationship of interaction between the contact surfaces,and to define the loads and boundary conditions.Four load cases,including compression,dorsal flexion,palmar flexion and torsion,were applied to compare the biomechanical properties.RESULTS AND CONCLUSION:(1)In the three groups of internal fixation models,the overall displacement of the internal fixation model was mainly concentrated on the articular surface of the distal radius under four load conditions.The maximum displacement of the model under the dorsal,palmar and torsion load conditions was 2-6 times that of the displacement under the axial load,indicating that the internal fixation system was the most stable under the axial load condition.(2)The stress on the internal fixation was much greater than the stress on the bone fracture fragments.The stress of the internal fixation was mainly concentrated in the area that near to the fracture end of the bone plate,among which the stress distribution of the volar fixed-angle anatomical plate,volar variable-angle locking plate was relatively uniform,and the stress concentration of the oblique T-locking plate was the most obvious.(3)Under compressive and torsional loads,the stress of the fracture fragments was mainly concentrated in the area that around the screw holes.Under dorsal and palmar flexion,it gradually expanded from the distal end to the proximal radius.Under the same load condition,the stress of the fracture block in the oblique T-locking plate fixation state was the highest,and the peak stress of the fracture fragments in the volar variable-angle locking plate fixation system was the lowest.The difference between the peak stress of the bone fracture fragments in the fixed state of the volar fixed-angle anatomical plate and the volar variable-angle locking plate was only in the range of 0.2-6.0 MPa.(4)It is indicated that compared with the oblique T-locking plate and the volar fixed-angle anatomical plate,the volar variable-angle locking plate has more uniform stress distribution,less displacement of articular surface,and the best stability in the internal fixation in the C1 type fracture of the distal radius.

BACKGROUND: At present, there are many ways to treat acromioclavicular joint dislocation, mainly based on clavicular hook plate, but the anatomical reconstruction of the trapezoid ligament and conoid ligament of the acromioclavicular ligament is the most important trend in the treatment of acromioclavicular joint dislocation. Endobutton plate has been widely promoted in recent years. A large number of randomized controlled trials and retrospective study showed that it has better efficacy and lower incidence of complications compared with the clavicular hook plate. OBJECTIVE: To evaluate the excellent and good rate and the short-term incidence of complication between Endobutton plate and clavicular hook plate in the treatment of acromioclavicular joint dislocation. METHODS: The Cochrane Library (1966-06/2017-05), PubMed (1966-06/2017-05), MEDLINE (1966-02/2017-05), EMbase (1984-01/2017-05), CNKI (1979-01/2017-05), VIP (1989-01/2017-05), and Wanfang (1982-01/2017-05) databases were searched by computer. Simultaneously, six major Chinese orthopedic journals were retrieved by hand, and the references included in the related articles were consulted. Randomized controlled trials addressing Endobutton plates and clavicular hook plates for the treatment of acromioclavicular joint dislocation were collected. The literatures were screened for inclusion criteria, and their qualities were evaluated. Meta-analysis was performed using RevMan 5.3 software. RESULTS AND CONCLUSION: (1) A total of 13 randomized controlled trials containing 800 patients were included in the study. 394 patients were treated with Endobutton plate and 406 patients with clavicular hook plate as controls. Among which, only one study was compared in three different ways; the rest were compared between Endobutton plate and clavicular hook plate. (2) Meta-analysis showed that the excellent and good rate of Endobutton plate was superior to that of clavicular hook plate in the treatment of acromioclavicular joint dislocation (P < 0.000 01). Compared with clavicular hook plate, the incidence of incision infection, acromioclavicular joint pain, limited activity and redislocation were lower in Endobutton plate (P=0.02, < 0.001, < 0.00001, 0.03). (3) These findings suggested that the effect of Endobutton plate was better than that of clavicular hook plate in the treatment of acromioclavicular joint dislocation. The incidences of incision infection, acromioclavicular joint pain, limited mobility, and redislocation were lower in Endobutton plate than in the clavicular hook plate. Although the article included many randomized controlled trials, the qualities of these articles are limited. We still need to design more strictly large-sample randomized controlled trials to increase the credibility of the evidence.