Objective To explore the feasibility of the reconstruction of three dimensional dynamic finite element model of the knee joint based on two-dimensional CT and MRI image data. To analyze the impact of mobile-bearing versus fixed-bearing platform prostheses of the knee joint on patellofemoral stress by the finite element method. Methods A three-dimensional digital model of the knee joint including bone,cartilage,meniscus, ligaments and tendons was reconstructed through the Mimics software. The best clinical bone cutting angle and implant placement position measurement were simulated according to the standard of total knee replacement by computers in a three-dimensionalknee model. A three-dimensional dynamic finite element model of mobile-bearing and fixed-bearing total knee arthroplasties was reconstructed finally. The data was analyzed by the SPSS 19.0 software. The test standard level α was 0.05. Results There was no significant difference in the peak value of patellofemoral stresses between fixed-bearing and mobile-bearing platform posterior cruciate-substituting prostheses at 0° ,30° ,60° ,90° ,or 120° of knee flexion(P>0.05). Conclusion There is no significant difference in the peak value of patellofemoral stresses between fixed-bearing and mobile-bearing platform prostheses.

Objective:To examine the expression of CLC-3 in colorectal tissues and the effect of CLC-3 on the viability and invasion of colorectal cancer (CRC) SW480 and SW620 cells. Methods:The mRNA levels of CLC-3 in CRC cell lines were determined by RT-PCR. CLC-3 expression was inhibited by adding DIDS or NPPB to the CRC cells. Subsequently, cell viability and invasion were assessed by CCK-8 assay and Transwell assay, respectively. In addition, the effects of DIDS and NPPB on the Wnt orβ-catenin signaling pathways were de-termined by Western blot analysis. Results:The mRNA level of CLC-3 was remarkably increased in the CRC tissues compared with that in normal colorectal tissues (P<0.05) and was positively correlated with the T stage of CRC. The blockade of CLC-3 inhibited the viability and invasion of CRC cells (P<0.05). The expression ofβ-catenin, C-myc, cyclin D1, Ki-67, and survivin were evidently reduced by the in-hibition of CLC-3 (P<0.05). Conclusion:The inhibition of CLC-3 decreases the cell viability and invasion of CRC cells by reducing the ex-pression of the proteins related to the Wnt orβ-catenin signaling pathway.

Objective To induce bone marrow mesenchymal stem cells(BMSCs) or bone marrow stroma stem cell(MSCs) to differentiate directionally towards chondrocytes in vitro and then identify the differentiated cells.Methods Bone marrow was harvested from the iliac bone of 16-week-old Japanese white rabbits.After gradient centrifugation,cultivation,amplification,the 3rd-passaged BMSC were implanted in six-hole-plate according to a certain proportion and induced by chondrogenic inducers including transforming growth factor-?1,dexamethasone and vitamin C.Chondrocytes were selected and fixed at different time.The features of chondrocytes were identified by toluidine blue staining and collagen types II immunohistochemical assay.Results The structure of cellular cartilage from BMSCs was uniformly positive of toluidine blue staining and collagen types II immunohistochemical staining.Conclusion Rabbit BMSC,obtained under the experimental conditions,develops stably,proliferates rapidly and is differentiated successfully into chondrocytes by induction in vitro.

BACKGROUND:The pedicle navigation template has many advantages,but there are still some problems.For example,poor soft tissue dissection leads to poor adhesion of the pedicle navigation template,resulting in screw path deviation;careful dissection of soft tissue to fit the pedicle navigation template leads to prolonged surgery time and increased bleeding;the design of the pedicle navigation template cannot predict the vertebral rotation and the impact of body position changes,resulting in the poor fitting. OBJECTIVE:To explore the utility of a new 5-point positioning point-contact pedicle navigation template in the case of scoliosis and complex pedicle. METHODS:A total of 20 patients with scoliosis and complicated pedicle admitted to the Department of Spinal Surgery,Guizhou Hospital,Beijing Jishuitan Hospital from February 2020 to February 2023 were selected for scoliosis orthopedics.During the operation,the 5-point positioning point-contact pedicle navigation template was used to guide the screws.According to the inclusion and exclusion criteria,34 cases were matched as the empirical nail placement group,and conventional barehanded nail placement was performed.The time of placement,the amount of bleeding,the number of fluoroscopies,the number of manual diversions,the level and accuracy of pedicle screws,the complications of placement,and the rate of correction of main curvature were compared between the two groups. RESULTS AND CONCLUSION:(1)There were no significant differences in sex,age,coronal Cobb's angle of the main curvature,bending Cobb's angle of the main curvature,pedicle variation,apex rotation,fusion segment,number of screws,level of screws,accuracy of screws,and rate of correction of main curvature between the navigation template group and the empirical nail placement group(P>0.05).(2)Compared with the empirical nail placement group,the navigation template group had more advantages in time of placement(P=0.034),amount of bleeding(P=0.036),number of fluoroscopies(P=0.000)and number of manual diversions(P=0.021).(3)There were 0 cases of screw-related complications in both groups.(4)In conclusion,the 5-point positioning point-contact 3D printing pedicle navigation template has a claw-like structure.It can firmly adapt to various deformities of the lamina articular process,avoid drift,and accurately place the screws.It has a point-like contact lamina structure to avoid extensive and complete dissection of the posterior structure,and reduce bleeding,operation time,and trauma.Pre-designed screw entry points and directions can reduce the number of fluoroscopy and operation time.Segmental design can avoid discomfort due to changes in anesthesia position.The operation is simple and the accuracy of screw placement is high.

OBJECTIVE: To explore the effectiveness of a new point contact pedicle navigation template (referred to as "new navigation template" for simplicity) in assisting screw implantation in scoliosis correction surgery. METHODS: Twenty-five patients with scoliosis, who met the selection criteria between February 2020 and February 2023, were selected as the trial group. During the scoliosis correction surgery, the three-dimensional printed new navigation template was used to assist in screw implantation. Fifty patients who had undergone screw implantation with traditional free-hand implantation technique between February 2019 and February 2023 were matched according to the inclusion and exclusion criteria as the control group. There was no significant difference between the two groups ( P>0.05) in terms of gender, age, disease duration, Cobb angle on the coronal plane of the main curve, Cobb angle at the Bending position of the main curve, the position of the apical vertebrae of the main curve, and the number of vertebrae with the pedicle diameter lower than 50%/75% of the national average, and the number of patients whose apical vertebrae rotation exceeded 40°. The number of fused vertebrae, the number of pedicle screws, the time of pedicle screw implantation, implant bleeding, fluoroscopy frequency, and manual diversion frequency were compared between the two groups. The occurrence of implant complications was observed. Based on the X-ray films at 2 weeks after operation, the pedicle screw grading was recorded, the accuracy of the implant and the main curvature correction rate were calculated. RESULTS: Both groups successfully completed the surgeries. Among them, the trial group implanted 267 screws and fused 177 vertebrae; the control group implanted 523 screws and fused 358 vertebrae. There was no significant difference between the two groups ( P>0.05) in terms of the number of fused vertebrae, the number of pedicle screws, the pedicle screw grading and accuracy, and the main curvature correction rate. However, the time of pedicle screw implantation, implant bleeding, fluoroscopy frequency, and manual diversion frequency were significantly lower in trial group than in control group ( P<0.05). There was no complications related to screws implantation during or after operation in the two groups. CONCLUSION The new navigation template is suitable for all kinds of deformed vertebral lamina and articular process, which not only improves the accuracy of screw implantation, but also reduces the difficulty of operation, shortens the operation time, and reduces intraoperative bleeding.
Humans ; Orthopedic Procedures ; Pedicle Screws ; Retrospective Studies ; Scoliosis/surgery* ; Spinal Fusion/methods* ; Spine ; Surgery, Computer-Assisted/methods*