ABSTRACT
Objective By developing an automatic procedure for optimization of femoro-tibial contact area for knee prosthesis, to summarize the influence pattern of design parameters on contact area, and discover the relationship between the maximum contact stress and contact area. Methods A parametric finite element (FE) model was developed in the Isight software, which included three components: automatic parameter changes for the geometric model, automatic modeling in the FE software, and automatic FE calculation. The automatic workflow was realized, and then contact areas were statistically analyzed. Results The FE model was validated by using Tekscan pressure distribution system. When the femoral sagittal radius was gradually close to the tibial sagittal radius, the contact area gradually reached to the maximum 295 mm2. The femoral sagittal radius had a positive effect on contact area, while the tibial sagittal radius had a negative effect. The maximum contact stress had a linear relationship with contact area approximately. Conclusions This study analyzed the influence of femoro-tibial sagittal radius on contact stress and contact area, and the research findings would provide references for the design on reducing wear of tibial insert in clinic.
ABSTRACT
Objective To explore the therapeutic effects of different surgery methods on early hypertensive intracerebral hemorrhage(HICH)in basal ganglia region in elderly patients and on prognostic factors analysis.Methods 89 elderly patients with early HICH were randomly divided into four groups according to surgery methods and whether their ICP was monitored.Group A(n=21)was given minimally invasive hematoma drainage,group B(n=23)was given small bone window for removal of hematoma,group C(n=21)and group D(n=24)was given ICP monitoring and corresponding management of ICP on the basis of group A and group B,respectively.The changes of intracranial pressure before and after operation,prognosis and post-operative complications were compared.Results The intracranial pressure was significantly decreased at 3rd day,7th day after operation in group C and D as compared with those in group A and B at the same time points(F=11.76,P<0.05),and the score of GCS was also higher in group C and D at 7th day after operation than in group A,B at the same time points(F=4.72,P<0.05).At 14th and 28th day after operation,the score of GCS was higher in group C than in group A and B(F=19.24,P<0.05),and higher in group C than in group D at 28th day after operation(F=22.26,P<0.05).The dosage of mannitol was significantly lower in group C and group D than in group A and group B(F=18.87,P<0.05).The incidence rate of post-operative complications was 14.3% in group C vs.28.6% in group A(P<0.05)and 20.8% in group D vs.47.8% in group B(χ2=7.04,P<0.05).The proportion of a good recovery and a light disability was significantly higher in group C and D(76.2% and 75.0%)than in group A and B(42.9% and 39.1%)respectively(χ2=14.99,all P<0.05).Conclusions Minimally invasive hematoma drainage shows the advantages of small trauma and a few complications for the treatment of elderly patients with early HICH,and its combination with ICP can early change intracranial pressure and further improves the prognosis.