BACKGROUND:Scoliosis is a complex spinal pathology characterized as a three-dimensional spine deformity combined with vertebral rotation. The finite element analysis can replace traditional biomechanical experiment for repeated experimental analysis and for processing digital simulation. It has been widely used in the study of scoliotic biomechanics.
OBJECTIVE:To emphasize the application of finite element analysis on the brace and surgical treatment of scoliosis.
METHODS:An online search of PubMed and Wanfang database was performed by using key words of“scoliosis, finite element”in Chinese for articles published between January 1986 and May 2013. A total of 38 papers related to finite element of scoliotic treatment, published in authorized journal and considered to be a representative, were selected.
RESULTS AND CONCLUSION: How to design an individualized brace in accordance with biomechanical characteristics of scoliosis is the hot topic. By using multi-imaging technology, the rib, chest bone and pelvis are introduced into the finite element models, in a broader attempt to analyze the optimal three-dimensional orthopedic force pattern for scoliosis. The results of relative research showed that, the ideal loading pattern is given at the protruding area of scoliosis. Finite element analysis can predict and evaluate the orthopedic procedure and effect of patients, thus assisting the design of reasonable orthopedic treatment scheme. Through finite element analysis, we can simulate and analyze the stress distribution of internal fixator in spine, which contributes to prevent the complications.

BACKGROUND:Establishment of high-quality finite element model is an important basis of biomechanical analysis. The reports on three-dimensional finite element model of complete adolescent idiopathic scoliosis are less. OBJECTIVE:To set up three-dimensional finite element model of PUMCIId1 adolescent idiopathic scoliosis for building ideal digitization platform for further biomechanical study. METHODS:A 14-year-old female patient with PUMCIId1 adolescent idiopathic scoliosis was included as volunteer for the current study. CT images obtained from CT transverse scanning from T 1 to sacrococcyx were imported into Mimics 16.0 software to form qualified three-dimensional geometric model, including thoracic cage, which was further delivered to Geomagic Studio 11.0 software to build three-dimensional finite element model by a series of modules and optimization of cleaning. The geometric model was imported to ANSYS 14.0 software to build complete three-dimensional finite element adolescent idiopathic scoliosis model by adding ligaments, setting unit type, and defining material properties. RESULTS AND CONCLUSION:A complete three-dimensional finite element model of PUMCIId1 adolescent idiopathic scoliosis was built successful y, consisting of 522 887 tetrahedron elements and 730 rod elements, a total of 523 617 units and 159 008 nodes. Three-dimensional finite element model of PUMCIId1 adolescent idiopathic scoliosis was lifelike, and can be used as the reliable digital model for further biomechanical analysis.

Objective To synthesize bovine serum albumin(BSA)-loaded liraqlutide(Lir)-nanoparticles coated with platelet membrane fragments(PMF)using a"bottom-up"nano-engineering chemistry technique,and to evaluate their cyto-compatibility and potential function of anti-oxidative stress.Methods PMF was extracted as reported previously.Lir@BSA nanoparticles were prepared by self-assembly method.PMF was coated on the sur-face of Lir@BSA nanoparticles by co-extrusion to prepare Lir@BSA-PMF.The physical and chemical properties of Lir@BSA-PMF particles were characterized as particle size,Zeta potential,transmission electron microscopy and particle size stability.The encapsulation efficiency,loading efficiency and cumulative release efficiency of liraglu-tide were calculated by enzyme-linked immunosorbent assay.Further,SDS-PAGE was used to analyze whether there was a similar membrane protein distribution of platelet membrane on Lir@BSA-PMF bionicnanocarrier.CCK-8 assay was used to verify the biocompatibility of the materials.Reactive oxygen species(ROS)experi-ment was used to explore the effect of Lir@BSA-PMF on cell oxidative damage.The uptake of cells on Lir@BSA-PMF bionic nano capsules was verified by cell phagocytosis experiment.Results Lir@BSA-PMF nanop-articles had a stable particle size of 25 nm with a spherical morphology,and a Zeta potential value of-25.5 mV.The encapsulation efficiency,loading efficiency and cumulative release efficiency of liraglutide were 85.56％,7.96％and 77.06％,respectively.SDS-PAGE analysis showed that the Lir@BSA-PMF bio-mimetic nano capsules retained the similar membrane protein distribution as platelet membrane.CCK-8 assay verified that the nanomaterials were non-cytotoxic.ROS results showed that Lir@BSA-PMF nanomaterials had obvious antioxidant properties.The results of cell phagocytosis showed that the cells had a good phagocytosis effect on Lir@BSA-PMF nanoparticles.Conclusions The nanoparticles Lir@BSA-PMF are successfully syn-thesized and have no effects on cells viability in vitro.The particles are taken up by cells and show a significant function of antioxidant damage.

Objective To evaluate the influence of different load carriages during military walking on the gait of lower limbs. Methods In a randomized cross-over design, 15 healthy young males were asked to perform self-paced walking with a normal uniform under a load carriage of 0 kg, 7.5 kg, 27 kg, and 50 kg for four times. The kinematics parameters of the pelvis, knee, and ankle were evaluated by the Vicon motion capture system and AMTI force plates. Results With increasing load carriage, the stride frequency relatively improved, whereas the stride reduced and the speed was maintained on the whole. The peak left/right hip flexion and extension angle and peak knee adduction angle were obviously affected by the load carriage, whereas the movement magnitudes could be maintained. The peak varus angle of the left ankle and peak valgus angle of the right ankle were also affected. The peak force and moment of the left/right knee and ankle increased. Conclusions With increasing load carriage, overall, the movement magnitudes of lower limb joints were maintained under the given loads, whereas the lower limb loads were increased, which could increase the potential risk of lower limb injuries.