ABSTRACT
Objective To evaluate the biomechanical properties of 3D printed individualized titanium alloy pelvic prosthesis in static and gait states by the method of finite element analysis. Methods Three patients with different types of pelvic tumors were treated by hemi-pelvic arthroplasty with resection of hemi-pelvis. CT and MRI were performed before the surgery, and the corresponding individualized titanium alloy pelvic prostheses were designed. The pelvic models were reconstructed with 3D reconstruction technique, and then assembled with the individualized pelvic prostheses. The human skeletal muscle model was established by AnyBody software to perform gait dynamics analysis. The stress distribution and stress concentration areas of 3 reconstructed pelvic models in static and gait states were obtained by ABAQUS. Results Under both static and gait conditions, the maximum stress of the 3 pelvic prostheses was smaller than the yield strength of the titanium alloy. The pelvic ring of the reconstructed pelvis could meet the rule of stress conduction. The patients’ daily life returned to normal condition after the surgery. Conclusions The effect of 3D prosthetic titanium prosthesis on recovery of pelvic ring is satisfactory, and its effectiveness and stability can meet the requirement of human biomechanics. The analytic results can provide references for clinicians and prosthesis designers.
ABSTRACT
Objective To evaluate the biomechanical properties of 3 D printed individualized titanium alloy pelvicprosthesis in static and gait states by the method of finite element analysis.Methods Three patients with different types of pelvic tumors were treated by hemi-pelvic arthroplasty with resection of hemi-pelvis.CT and MRI were performed before the surgery,and the corresponding individualized titanium alloy pelvic prostheses were designed.The pelvic models were reconstructed with 3D reconstruction technique,and then assembled with the individualized pelvic prostheses.The human skeletal muscle model was established by AnyBody software to perform gait dynamics analysis.The stress distribution and stress concentration areas of 3 reconstructed pelvic models in static and gait states were obtained by ABAQUS.Results Under both static and gait conditions,the maximum stress of the 3 pelvic prostheses was smaller than the yield strength of the titanium alloy.The pelvic ring of the reconstructed pelvis could meet the rule of stress conduction.The patients' daily life returned to normal condition after the surgery.Conclusions The effect of 3D prosthetic titanium prosthesis on recovery of pelvic ring is satisfactory,and its effectiveness and stability can meet the requirement of human biomechanics.The analytic results can provide references for clinicians and prosthesis designers.
ABSTRACT
<p><b>OBJECTIVE</b>To explore the occupational stress factors associated with the prevalence of metabolic syndrome (MS) among male policemen.</p><p><b>METHODS</b>Using cluster sampling method, we selected four Public Security Bureau within the jurisdiction of the station now in some city. All the male police were included as research objects, and finally 1490 persons were selected, health and occupational stress inventory-revised (OSI-R) questionnaire were used for epidemiological surveys, and anthropometric examination and chemical indicators were also measured at the same time. The analysis methods were chi-square test and unconditional logistical regression.</p><p><b>RESULTS</b>Among the 1490 of research objects, 1483 completed the questionnaire, and 1480 of the eligible questionnaires were available.237 cases were MS, and the prevalence rate was 16.0%(237/1480). The number of cases who were high, moderate and lack of occupational stress in MS group were 8, 39 and 23, that in non-MS were 14, 114 and 131, respectively. The odds of occupational stress with the highest and medium among policemen than who were lack were 4.82 (95%CI: 1.50 - 15.41) and 3.33 (95%CI: 1.62 - 6.79); the average score of role ambiguity, role insufficiency and responsibility in the group of MS were (38.76 ± 6.83), (25.74 ± 7.22), (25.76 ± 6.27); and that in non-MS were (37.55 ± 6.85), (24.50 ± 6.58), (25.05 ± 5.95). The logistical regression analysis showed that: the likely three occupational risk stress factors which influencing the prevalence of MS were role ambiguity, role insufficiency and responsibility, and the OR (95%CI) were 1.06 (1.02 - 1.10), 1.04 (1.02 - 1.07) and 1.03 (1.01 - 1.06), respectively.</p><p><b>CONCLUSION</b>Role ambiguity, role insufficiency and responsibility were the occupational risk stress factors associated with the prevalence of MS among male policemen.</p>