10.3969/j.issn.2095-4344.2013.25.023

In the present study, a three dimensional finite-element model of the human pelvic was reconstructed, and then, under different acetabular component position (the abduction angle ranges from 30 degrees to 70 degrees and the anteversion ranges from 5 degrees to 30degrees) the load distribution around the acetabular was evaluated by the computer biomechanical analysis program (Solidworks). Through the obtained load distribution results, the most even and reasonable range of the distribution was selected; therefore the safe range of the acetabular component implantation can be validated from the biomechanics aspect.
Acetabulum ; diagnostic imaging ; Arthroplasty, Replacement, Hip ; Biomechanical Phenomena ; Cadaver ; Computer Simulation ; Computer-Aided Design ; Finite Element Analysis ; Hip Prosthesis ; Humans ; Imaging, Three-Dimensional ; Models, Biological ; Pelvis ; diagnostic imaging ; Range of Motion, Articular ; physiology ; Stress, Mechanical ; Tomography, Spiral Computed

BACKGROUND: Adult acetabular dysplasia in advanced stage combined with hip joint osteoarthritis should undergo total hip replacement. The severity of acetabular lesion is various in different patients, which leads to significantly increased difficulty in reestablishing acetabulum. Acetabular medial wall displacement osteotomy can solve the component of acetabular prosthesis, but the displacement range of the acetabular medial wall following osteotomy is controversial.OBJECTIVE: To look for a suitable displacement range of acetabular medial wall following osteotomy by computer-aided design finite element analysis.METHODS: SolidWorks 2008 software was used to establish three-dimensional models of acetabular dysplasia pelvis. Acetabular medial wall displacement osteotomy was simulated to make acetabular medial wall bone displace from 2 mm bone contact to 7 mm bone contact in the pelvic cavity. One experimental group was set at 1 mm intervals, totally 10 experimental groups. The acetabulum in each group was split into four quadrants. The prosthesis acetabulum-bone interface in each group was analyzed by computer simulation contrast mechanics experiment. The Mises stress and shear stress values were measured between acetabular prosthesis and bone interface.RESULTS AND CONCLUSION: In groups 1, 5, 6, 9 and 10, the Mises stress was unevenly distributed in posterior inferior, anterior superior and anterior inferior quadrants. In groups 2, 3, 4, 7 and 8, the Mises stress was evenly distributed in posterior inferior,anterior superior and anterior inferior quadrants. Of them, the stress was most even in the group 4. In groups 2, 3, 4, 7 and 8, the shear stress was evenly distributed in the above-mentioned three quadrants. The shear stress was lowest in the groups 7 and 8.These indicate that joint force in the acetabulum mainly focused in the posterior superior quadrant. With the displacement of acetabular cup, the contact area of acetabular cup and bone would gradually increase, which finally increased the Mises stress in the contact surface. However, shear stress decreased with displacement of acetabular medial wall. Therefore, the suitable displacement range of acetabular medial wall osteotomy is 1 mm away from the pelvic cavity and 1 mm complete embolism in the pelvic cavity. The optimal position was 1 mm complete embolism in the pelvic cavity.

Copolymer of polycaprolactone (PCL) and polylactic acid (PLA) was synthesized and catalyzed using Y (CF3COO)3/AL (I-Bu)3. The biocompatibility was evaluated by means of biochemistry, immunocytochemistry, and by cytotoxity test. This novel orthopedic biodegradable polymer can serve as an ideal orthopedic biodegradable implants, and adjustment of molecular weight and ratio of polymers can control its degradation period.
Absorbable Implants ; Animals ; Bone Substitutes ; Catalysis ; Female ; Lactic Acid ; chemistry ; Male ; Materials Testing ; Polyesters ; chemistry ; Polymers ; chemistry ; Rats ; Rats, Wistar

Objective　To investigate the ultrastructural changes of brain vessels and cells after alcoholism in rats and the underlying mechanisms.Methods　Wistar male rats were given alcohol intragastrically for 4 weeks to induce chronic alcoholism model.To observe the ultrastructural changes related to brain vascular and cells damage after alcohol intoxication in rats by a transmission electron microscope.Results　The shape of cerebellar capillary endothelial cells was irregular in the alcohol intoxication group，there were fewer organelles in the cytoplasm.The nuclei are irregularly shaped,the nuclei are not obvious,irregular shape.The mitochondria in the frontal lobes are swollen,crest fracture,reduced number,the ribosomes attached to the crest fall off.The tubular rough endoplasmic reticulum is fractured,the interval between each other is widened,the quantity is reduced,the ribosomes attached to the outer surface of the tube membrane fall off.Mild demyelinating changes were observed in the hippocampus,and the lamellar myelin sheath composed of multiple plasma membranes was slightly detached and damaged.Conclusion　Alcoholism can cause the change and damage of the ultrastructure of cerebrovascular and related cells.To provide basic research theories and ideas for subsequent prevention and treatment.