Résumé
BACKGROUND:Three-dimensional finite element studies found that the instal ation location of the hip prosthesis is closely related to the effects of hip replacement, but studies on different anteversion and abduction angle of the hip prosthesis mounting position on the effects of hip biomechanics are not much. OBJECTIVE:To analyze the biomechanical characteristics of different prosthetic positions in hip arthroplasty using three-dimensional finite element analysis. METHODS:One healthy volunteer was selected and data of pelvis and femur were col ected. Three-dimensional geometric model of this volunteer was established and received finite element network partitioning. CT scan was used to obtain prosthesis model data and accurate prosthesis model was established. 16 kinds of different prosthesis position model of hip replacement were established. Vertical y downward force of 780 N was applied on the top of sacroiliac joint and pubic symphysis. The acetabular stress peak, femoral stress peaks, polyethylene liner peak stress and polyethylene liner damage zone volume of 16 kinds of model were observed. RESULTS AND CONCLUSION:(1) The acetabular stress peak, femoral stress peaks, polyethylene liner peak stress and polyethylene liner damage zone volume of 16 kinds of different prosthesis position model of hip replacement, anteversion angle 10° abduction angle 50° got the best results. The acetabular stress peak was 51.23 MPa;femoral stress peak was 26.34 MPa. Polyethylene liner peak stress was 5.288 MPa and polyethylene liner damage zone volume was 2.239×10-7 m3. (2) These results indicated that anteversion angle 10° abduction angle 50° is the ideal hip replacement degree. The peak stresses of acetabulum, femur, and polyethylene liner at this instal ation angle are minimum;polyethylene liner damage zone volume is also minimum. This can provide data for clinical reference.
Résumé
BACKGROUND:Lumbar spinal stenosis is clinical repaired with decompression, bone fusion and internal fixation, and different internal fixation materials can be chosen during the surgery. OBJECTIVE:To explore the influence of polyetheretherketone (PEEK) pedicle screw fixation combined with interbody fusion on the bone fusion rate of patients with lumbar spinal stenosis. METHODS:A retrospective analysis was performed in 63 cases of lumbar spinal stenosis undergoing decompression and interbody fusion. These patients were divided into control group (titanium internal fixation system,n=31) and experimental group (PEEK pedicle internal fixation system,n=32) according the internal fixation materials folowed by posterior spinal decompression with interbody fusion. The Oswestry dysfunction index scores before and 4, 12, 24 weeks postoperatively and bone fusion rates at 4, 12, 24 weeks postoperatively were compared between the two groups. RESULTS AND CONCLUSION:Oswestry dysfunction index scores showed a gradual decline in both two groups before and 4, 12 and 24 weeks after treatment, but there was no difference at different time (P > 0.05). At 4 and 24 weeks after treatment, there was no difference in the bone fusion rates between the two groups (P > 0.05), but at 12 weeks after treatment, the bone fusion rate in the experimental group was better than that in the control group (P < 0.05). During the surgery, no infection and other adverse events occurred in the two groups. These results indicate that both PEEK and titanium internal fixation systems for lumbar tube stenosis have obtained good results, but PEEK material has a better role in the bone fusion at 4-12 weeks after internal fixation.
Résumé
BACKGROUND: In recent years, al kinds of absorbable internal fixation materials have been used in the clinical treatment of patel ar transverse fractures. OBJECTIVE: To investigate the repairing effect of absorbable internal fixation materials on patel ar transverse fractures. METHODS: Total y 102 cases of fresh patel ar transverse fractures were included 62 males and 40 females cases, with a mean age of (41.85±11.15) years, and according to treatment methods, they were divided into two groups: observation group (n=52) using absorbable screws for reconstruction and control group (n=50) using Kirschner wire repair. At 12 months after repair, Lysholm knee function score were measured and evaluated, and the occurrence of adverse events was recorded. RESULTS AND CONCLUSION: The knee function score and excel ent rate of the observation group were significantly higher than those of the control group (both P < 0.05). In the observation group, there were four cases of fracture displacement, but no skin irritation and other adverse events occurred; in the control group, there were two cases of nonunion and five cases of skin irritation or internal fixation loosening and slippage. Therefore, there was a higher incidence of adverse events in the control group compared with the observation group (P < 0.05). These experimental results show that the use of absorbable screws in the repair of patel ar transverse fracture can promote the functional recovery of the knee joint, with good biocompatibility.
Résumé
<p><b>OBJECTIVE</b>To downregulate the expression of pituitary tumor transforming gene 1 (PTTG1) in osteosarcoma (OS) cells by siRNA technology and to investigate related biological impact on cell proliferation, cell cycle and cell invasion of OS.</p><p><b>METHODS</b>Three OS cell lines and osteoblast hFOB1.19 cell line were used in this study. Control siRNA and PTTG1 siRNA were employed to transfect OS U2OS cells, and PTTG1 protein level was detected by Western blot after the transfection. Effects of PTTG1 siRNA on cell proliferation, cell cycle and cell invasion were investigated by CCK-8, flow cytometry and Boyden chamber, respectively. Finally, activity of Akt and its downstream target gene expression were analyzed by Western blot in U2OS cells upon various treatments.</p><p><b>RESULTS</b>Expression of PTTG1 protein in 3 OS cells (MG-63, SaOS-2 and U2OS) was significantly higher than that in osteoblast hFOB1.19, among which U2OS cells displayed the highest level. PTTG1 siRNA markedly downregulated the expression of PTTG1 protein in U2OS cells, leading to obvious inhibition of cell proliferation, altered cell cycle distribution and reduced ability of invasion of U2OS cells. Moreover, downregulation of PTTG1 reduced the expression of p-Akt (S473 and T308), MMP-2 and MMP-9 proteins, along with enhanced expression of p21 and E-cadherin proteins.</p><p><b>CONCLUSIONS</b>PTTG1 may be tightly linked to the development of OS and therefore may serve as a novel target for precision therapy of OS.</p>