Objective To investigate the relative motion between the femoral component and the tibial insert through the technology of fluoroscopy and digital model.Methods Sixteen female patients (16 knees) with knee osteoarthritis were performed TKA (GENESIS Ⅱ) from July 2007 to June 2008.The mean age was 66.4 years (range from 56 to 76 years).All patients were followed up 48 months to 60 months,with the mean of 56±3 months.The postoperative clinical function was evaluated by Knee Society Score (KSS).To match the digital model to the imaging data of fluoroscopy using 2D-3D automatic registration technology and reconstruct motion of the knee after TKA.The movement of contact position between femoral medial and lateral condyle and tibial insert and tibial internal rotation during flexion were measured.The contact time and range between femoral cam and tibial post were analyzed.Results The cases were statistically improved in KSS postoperatively,knee score was 93±5 and function score 88±13.The range of movement for femoral medial condyle was 8.5±2.5 mm,and the lateral condyle was 9.5±4.8 mm,the range of tibial internal rotation was 2.5°±8.4°.The contact of cam and post was observed after 30°-40° flexion of the knee,and the range was 8.0±1.8 mm.The greater tilting angle of the tibial plateau was,the later contact between cam and post happened.Conclusion The kinematics of tibiofemoral joint after TKA is different from the kinematics of normal knee.With knee flexion within 10°-30°,femoral medial condyle moves forward.When flexion is greater than 40°,medial and lateral condyle begins rollback.The time of contact of cam and post is relative to tibial prosthesis slope.

Objective:To observe the effect of electro-acupuncture (EA) on learning, memory and the differentiation of neural stem cells in the hippocampus in the presence of chronic cerebral ischemia.Methods:A total of 120 male Sprague-Dawley rats had chronic cerebral ischemia induced by bilateral ligation of the common carotid arteries. The model was successfully established in 104 of them, and they were randomly divided into a model group and an EA group, each of 52. The EA group was given 20 minutes of EA at acpoints Baihui and Dahui every day for 7 days, followed by an interval of 2 days. The current output was 1mA and the frequency was 15Hz. The model group was not given any intervention. One, 2, 4 and 6 weeks after the modelling, 6 rats from each group were injected with BrdU, and any proliferation and differentiation of neural stem cells was observed. The rats′ learning and memory were also evaluated using the Morris water maze, and neurogenesis of in the dentate gyrus was observed using BrdU+ NeuN and BrdU+ GFAP double-labelled immunofluorescence.Results:The learning and memory of the EA group were significantly better than those of the model group 2, 4 and 6 weeks after the modelling. After two weeks BrdU+ NeuN and BrdU+ GFAP-positive cells were found in the granule cell layer of the hippocampus, and compared with the model group, there were siginificantly more such neurons in the EA group. The gliocyte levels were not significantly different.Conclusion:Electro-acupuncture can improve learning and memory in the face of chronic cerebral ischemia by promoting the differentiation of neural stem cells.

Objective:To observe the expression of noggin mRNA in the hippocampus of rats with chronic cerebral hypoperfusion, and explore the effect of electroacupuncture (EA) at the " baihui" and " dazhui" acupoints on their learning and memory and on hippocampal neurogenesis.Methods:In total, 120 Sprague-Dawley rats had cerebral hypoperfusion induced by permanent bilateral ligation of the common carotid artery. The 104 successfully induced were divided at random into a model group and an EA group, each of 52. The EA group was given EA on the baihui and dazhui acupoints for 20 minutes daily for seven days followed by a two-day break. The output current was 1mA at 15Hz. No special treatment was given to the model group. After one, two, four and six weeks of treatment, 6 rats were given BrdU injections to observe the proliferation and differentiation of neural stem cells. Learning and memory were assessed using the Morris Water Maze. The expression of noggin mRNA and neurogenesis in the dentate gyrus of the hippocampus were measured using reverse-transcription polymerase chain reactions and immunohistochemistry.Results:After one, two and five weeks of intervention, the average learning and memory ability of the EA group were significantly better than those of the control group. The average expression of noggin mRNA was significantly higher in the EA group than in the model group at the same time points. Compared with the model group, there were more BrdU-positive cells in the hippocampal dentate gyrus in the EA group, and the number decreased with the prolongation of ischemia. Pearson correlation analysis showed that the levels of noggin mRNA in the hippocampus of both groups were positively correlated with their number of BrdU-positive cells. The correlation was stronger in the EA group than in the model group.Conclusions:Electroacupuncture can promote hippocampal neurogenesis in rats with chronic cerebral hypoperfusion by regulating the expression of hippocampal noggin mRNA, thereby improving their spatial learning and memory ability.