ABSTRACT
Objective To investigate the method of modeling, finite element modeling and AnyBody musculoskeletal multi-body dynamics simulation technique analyze the biomechanics of clinical orthopaedic surgery. Methods The AnyBody software was used to establish the musculoskeletal motor model of the individualized upper limbs according to the height, weight and CT data of the volunteers. The flexion motion of the elbow in normal people was simulated, and the muscle force, joint force, torque, constraint condition of the humerus during the flexion movement were derived and used as the boundary conditions of finite element analysis.Then, the 3D reconstruction was conducted in the MIMICS software based on CT data. In the Geomagic Studio software, the humeral curved surface and position coordinate matching were completed, and grid division and material assignment were done in the HyperMesh software. Finally, the 3D reconstruction for finite element model of the humerus was introduced into ABAQUS software. The boundary condition data derived from the AnyBody software were applied and the stress calculation analysis was performed. Results The results of the stress and displacement of the humerus during elbow flexion motion were calculated in the ABAQUS software. The maximum stress and displacement of the humerus were 0.76 MPa and 20 μm when flexion of the elbow joint was about 90°. Conclusions A continuous dynamic analysis of humeral stress and displacement during elbow flexion motion was realized, which was more consistent with the requirements of human physiological anatomy and could provide an efficient analysis platform and a new way for studying clinical orthopedic problems.
ABSTRACT
Objective To analyze the clinical value of immature granulocytes in peripheral blood for prediction of persistent systemic inflammatory response syndrome (SIRS) in patients with acute pancreatitis (AP). Methods 1 973 patients with AP in Hunan People's Hospital from 2012 to 2017 were retrospectively enrolled and divided by SIRS duration into the persistent SIRS group, temporary SIRS group and non-SIRS group. The independent risk factor for persistent SIRS in AP patients was evaluated by Logistic regression analysis, and predictive value of immature granulocytes for persistent SIRS in AP patients was analyzed by the receiver operating characteristic (ROC) curve. Results These 1 973 AP patients (1 165 males, 59.0%) with an average age of 49 (40, 60) years old, including 288 persistent SIRS, 189 temporary SIRS and 1 496 non-SIRS cases. There was no significant difference in gender, age and etiology among three groups. Compared with non-SIRS group, more severe symptoms were observed in the temporary and persistent SIRS groups. Moreover, The acute physiology and chronic health evaluation Ⅱ(APACHEⅡ), CT severity index (CTSI), multiple organ failure (MOF) and acute respiratory distress syndrome (ARDS) incidence, mortality and C-reactive protein (CRP), white blood cell count (WBC), procalcitonin (PCT) and immature granulocytes in persistent SIRS group were further higher than those in the temporary SIRS group [APACHEⅡ: 9 (6, 12) vs. 5 (3, 7), CTSI: 6 (4, 6) vs. 4 (3, 6), MOF incidence: 92.0% vs. 32.8%, ARDS incidence: 39.9% vs. 10.1%, morbidity: 11.1% vs. 4.2%, CRP (mg/L): 25.00 (0.80, 212.25) vs. 0.80 (0.80, 123.50), WBC (×109/L): 15.17±6.78 vs. 14.84±5.86, PCT (μg/L): 0.23 (0.10, 1.76) vs. 0.10 (0.10, 0.31), immature granulocytes: 1.95 (0.90, 4.95) % vs. 0.80 (0.40, 2.10) %, all P < 0.05]. Logistic regression analysis showed that besides pancreatic necrosis, WBC and CRP, immature granulocyte was an independent risk factor for persistent SIRS associated with AP [odds ratio (OR) = 1.844, 95% confidence interval (95%CI) = 1.372-2.220]. ROC curve showed that immature granulocytes had better predictive value for persistent SIRS, the area under the curve (AUC) was 0.806, which was significantly higher than the APACHEⅡ (AUC = 0.783), CTSI (AUC = 0.752), PCT (AUC = 0.676), CRP (AUC = 0.677), WBC (AUC = 0.644). The cut-off value of immature granulocyte was 0.65%, the sensitivity was 84.0%, the specificity was 66.3%, the positive predictive value was 62.4%, and the negative predictive value was 76.3%. Conclusion Immature granulocyte in peripheral blood is a potential indicator for persistent SIRS in AP patients.