The geometric bone model of patients is an important basis for individualized biomechanical modeling and analysis, formulation of surgical planning, design of surgical guide plate, and customization of artificial joint. In this study, a rapid three-dimensional (3D) reconstruction method based on statistical shape model was proposed for femur. Combined with the patient plain X-ray film data, rapid 3D modeling of individualized patient femur geometry was realized. The average error of 3D reconstruction was 1.597–1.842 mm, and the root mean square error was 1.453–2.341 mm. The average errors of femoral head diameter, cervical shaft angle, offset distance and anteversion angle of the reconstructed model were 0.597 mm, 1.163°, 1.389 mm and 1.354°, respectively. Compared with traditional modeling methods, the new method could achieve rapid 3D reconstruction of femur more accurately in a shorter time. This paper provides a new technology for rapid 3D modeling of bone geometry, which is helpful to promote rapid biomechanical analysis for patients, and provides a new idea for the selection of orthopedic implants and the rapid research and development of customized implants.
Objective To explore the clinical value of measuring angle alpha ( α) in the descending limb of maximum expiratory flow-volumem ( MEFV) curve in chronic obstructive pulmonary disease ( COPD) and bronchial asthma. Methods From MEFV curves, angle αand other parameters were measured in 157 individuals with COPD and 149 patients with asthma who received pulmonary function test in Zhongshan Hospital, from November 2008 until December 2009. The results were grouped and analyzed.The area under ROC curve of the angle αwas measured in the patients with COPD and compared with asthma. Results The angle αlessened with the increasing degree of airway obstruction in the patients with COPD and asthma( P lt;0. 01, P gt;0. 05) . Tangent( 180 - α) and FEV1. 0 were correlated either in the COPD group or in the asthma group( r = - 0. 640, P =0. 000; r = - 0. 206, P = 0. 012) . There was no statistical difference in the angle α between the COPD group and the asthma group when the patients had mild obstructive ventilation disorders( P =0. 177) . The angle αin the COPD group was smaller than that in the asthma group when the patients had moderate and severe obstructive ventilation disorders( P =0. 000, P =0. 000) . Area under ROC curves of the angle αin the patients with COPD who had mild, moderate and severe obstructive ventilation disorders were 0. 431, 0. 846 and 0. 928 respectively. In moderate obstructive ventilation disorders, the optimal diagnostic cutoff point was 135. 5 degree which was capable of differentiating COPD and asthma with a sensitivity of 81. 7% , a specificity of 74. 2% , a positive predictivevalue of 75. 4% , and a negative predictive value of 80. 7% . In severe obstructive ventilation disorders, the optimal diagnostic cutoff point was 129. 5 degree with a sensitivity of 87. 5% , a specificity of 84. 0% , a positive predictive value of 94. 3% , and a negative predictive value of 77. 8% . Conclusions Angle αin the descending limb of MEFV curve can assess the degree of airway obstruction in COPD, whereas it just reflect the presence of airway obstruction in asthma. Differences in Angle αare associated with pathological and pathophysiological differences between COPD and asthma, which will help for deffirentiating diagnosis.
Posterior-stabilized total knee prostheses have been widely used in orthopedic clinical treatment of knee osteoarthritis, but the patients and surgeons are still troubled by the complications, for example severe wear and fracture of the post, as well as prosthetic loosening. Understanding the in vivo biomechanics of knee prostheses will aid in the decrease of postoperative prosthetic revision and patient dissatisfaction. Therefore, six different designs of posterior-stabilized total knee prostheses were used to establish the musculoskeletal multibody dynamics models of total knee arthroplasty respectively, and the biomechanical differences of six posterior-stabilized total knee prostheses were investigated under three simulated physiological activities: walking, right turn and squatting. The results showed that the post contact forces of PFC Sigma and Scorpio NGR prostheses were larger during walking, turning right, and squatting, which may increase the risk of the fracture and wear as well as the early loosening. The post design of Gemini SL prosthesis was more conductive to the knee internal-external rotation and avoided the edge contact and wear. The lower conformity design in sagittal plane and the later post-cam engagement resulted in the larger anterior-posterior translation. This study provides a theoretical support for guiding surgeon selection, improving posterior-stabilized prosthetic design and reducing the prosthetic failure.
Objectve To measure the serum levels of human IL-32 and explore the clincal implication in patients with chronic obstructive pulmonary disease( COPD) at acute exacerbation or stable stage. Methods 120 patients with COPD were recruited, including 60 patients with acute exacerbation COPD and 60 patients with stable COPD from October 2010 to May 2011. Thirty healthy nonsmoking volunteers were included as controls. The concentrations of interleukin-8 ( IL-8) , tumor necrosis factor alpha ( TNF-α) , and IL-32 in serum were measured by enzyme-linked immunosorbent assay ( ELISA) . The correlations among IL-32, IL-8, TNF-αand lung functions were investigated. The datas were analyzed using a statistical software package ( SPSS13. 0) . Variables were compared with one-way ANOVA . The correlations between variables were analyzed using Pearson’s correlation coefficient or Spearman correlation coefficient. Results SerumIL-32 level was significantly higher in AECOPD patients [ ( 174. 56 ±88. 15) ng/L] than that in healthy subjects [ ( 59. 41 ±20. 98) ng/L] and in stable COPD patients [ ( 89. 40 ±33. 84) ng/L]( P lt;0. 05) while serum IL-32 level was also significantly higher in stable COPD patients than in healthy subjects( P lt;0. 05) . The serumIL-32 1evel in patients with acute exacerbation COPD and stable COPD was positively correlated with the serumIL-8 level, TNF-αlevel ( respectively P lt;0. 01) . The serumIL-32 level was negatively correlated with FEV1 /predicted value, FEV1 /FVC and PaO2 ( respectively, P lt;0. 01) . There was no statistical significance of the serum IL-32, IL-8 or TNF-α levels in COPD patients with different severity ( all P gt;0. 05) . Conclusion The serumlevel of IL-32, a newpro-inflammatory cytokine is elevated in COPD patients, which may be involved in the pathogenesis of inflammation in COPD.