Objective To determine whether the number of distal locking bolts have an impact on the biomechanical feature of locking intramedullary nails. Methods Twenty locking nails tested were divided into two groups randomly. One distal locking screw was used in first group (single bolt group); and two were used in the other group (double bolts group). After being fixed in the model, compressive and torsional strength of the interlocking nail were measured in each group. Results The average maximum strength of double bolts group and single bolt group was 2 160 N and 1 880 N respectively in compression tests(P＜0.05). In torsion tests, the average maximum torsional moment of double bolts group and single bolt group was 55.8 Nm and 55.5 Nm respectively(P＞0.05), the average maximum torsional angle indouble bolts group and single bolt group was 58.3° and 58.0° respectively(P＞0.05). Conclusion Single distal bolt used in interlocking nail system can meet clinical request, though the whole biomechanical behavior isnot better than that of double bolts. One distal bolt is enough for the stable fracture types and double bolts should be used in the serious fracture types.
Objective To compare and evaluate the capability of pure autogenous bone and the enhanced autogenous bone combined with bone morphogenetic protein in bone repair of femoral head. Methods Eighteen femoral heads of 9 dogs weredrilled by trephine, 4 mm in diameter, followed by respective implantations of autogenous bone grafting (group B) and of the enhanced autogenous bone composite, combined with bone morphogenetic protein (group C), with the selfrepair of bone defect as the control (group A). Three, six, nine weeks after the operation, radiological examination, computerized tomography, light and electronic microscopes were performed to investigate the bone healing of the defect in the femoral head. Results In group A, it could be observed that there washematoma organization and delayed woven bone formation in the 3rd week after operation, and therewas little replacement of woven bone by bone trabecula in the 9th week; in group B, the autogenous bone implanted were dead in the 3rd week and maintained in situ in the 9th week; in group C, active new bone formation, either endochondral or intramembranous ossification, was found in the 3rd week and entire repair of the bone defect by bone trabecula in the 9th week after operation. Conclusion The enhanced autogenous bone combined with bone morphogenetic protein could promote reconstruction of the bone defect in femoral head, superior to pure autogenous bone which could provide a framework for the new bone formation.
Objective To investigate the expression levels of osteoprotegerin (OPG) and receptor activator of NF-κB l igand (RANKL) mRNAs in bone tissues of the femoral head of the patients suffering glucocorticoid-induced osteonecrosisof the femoral head (ONFH), and to discuss the relationship between OPG/RANKL and ONFH. Methods Between March2007 and March 2008, bone tissues of the femoral head were collected as the experimental material from 35 patients suffering ONFH (experimental group) and from 21 patients suffering fracture of femoral neck (control group). The ratio of men to women in both groups was 4 ∶ 3, whose age was 41-70 years old (55.34 on average in the experimental group and 55.33 on average in the control group). The experimental group received over 3 weeks’ glucocorticoid treatment or more than 1 week’ s high-dose glucocorticoid treatment in recent 2 years, while the control group never received more than 1 week’s hormone treatment. In the two groups, the microstructure of bone tissues of the femoral head was detected by HE staining and the bone tissue total RNA was extracted, and then the expression levels of OPG mRNA and RANKL mRNA were examined by realtime quantitative PCR (RTQ-PCR) for each sample. Results HE staining: bone trabeculae and bone units were replaced by interrupted bone fragments, which were surrounded by many inflammatory granulation tissues and few osteocytes were seen in bone lacunae in the experimental group. In the control group, bone trabeculae and bone units were made by complete lamellar bones which surrounded blood vessels and osteocytes were seen in lacunae. RTQ-PCR testing: in the experimental group, OPG mRNA and RANKL mRNA were 1.35 ± 0.42 and 4.36 ± 1.35, respectively, while in the control group they were 1.78 ± 0.63 and 3.49 ± 1.02, respectively. The expression level of OPG mRNA in the experimental group was significantly lower than that in the control group, and the expression level of RANKL mRNA of the former was significantly higher than the latter. The OPG mRNA/ RANKL mRNA ratio in the xperiment group (0.34 ± 0.16) was significantly lower than that in the control group (0.54 ± 0.20), and there was significant difference (P lt; 0.05). Conclusion The glucocorticoid-induced ONFH may be related to the expression levels of OPG mRNA/RANKL mRNA in bone tissues.
BJECTIVE: To discuss the clinical effect and the application of AF device fixation system and PROSPACE interbody fusion cage on treating lumbar spondylolisthesis. METHODS: Twenty-one cases of lumbar spondylolisthesis treated by operation from 1999 to 2002 were analyzed retrospectively (13 males and 8 females, 25-66 years old averaging 42 years). We had thorough decompression on the part of nerve compression and had replacement and fixation of the slippage vertebral body with the AF transpedicular screw/rod system so that the normal spine physiological curvature could be recovered, and then performed the posterolateral interbody fusion with implanting the PROSPACE filled with autograft bones. RESULTS: All the patients were followed up for 3 months to 3 years with an average of 15 months. The preoperation symptoms improved in 20 cases (95.2%). CONCLUSION: The combination of AF device fixation system and PROSPACE interbody fusion cage can relieve effectively nerve compression, recover the normal spinal physiological curvature, maintain the height of interbody and promote the nerve fusion. It is reliable and effective in the treatment of spondylolisthesis.
Objective To evaluate the selection of the type of prosthesis in revision hip arthroplasty. Methods There were 33 hips in our study,male in 7 hips and female in 26 hips.The average age of the patients were 59 years.The reasons ofthe revision included aseptic loosing in 22 hips, infection in 8 hips(2 infection hips with discharging sinuses),and acetabular erosion in 3 hips.The operationsfor revision were 13 cemented and 12 cementless acetabular prosthesis with autograft inmorselized form;the femoral revision were all selected in cemented prosthesis.The revision for infection hip were all cemented prosthesis of extensively porouse-coated. Results The average follow-up duartion was 3.9 years and 11 months.There was a radiolucency but no clinical instability accompanied in 2 hips and remaining moderate pain in4 hips.No dislocation and fracture were seen in the series.Harris score were improved to 82.4(68.88). Conclusion The commonest reason of revision hip arthroplasty was aseptic loosing.The acetabular prosthesis in revision could select cemented or cementless components and femoral prosthesis could select extensively coated stem.The cemented components could yield good results in infection hips revision.
Objective To compare the clinical effect of reamed and nonreamed intramedullary interlocking nails on treating open tibial fractures. Methods From February 2002 to February 2004, 92 cases of open tibial fractures (86 patients) were treated with intramedullary interlocking nails. Of the 86 patients, 65 were male and 21 were female. Their age ranged from 18 to 68 years (36.5 on average). Of the 92 cases, 54 were in the reamed group and 38 in the nonreamed group. Patients moved with the support of crutch after their wounds were healed. Results All patients were followed up regularly for 6 to 24months. Infection rate in the reamed group and nonreamed group was 20.3% and 5.3% respectively, and there was significant difference between them (Ｐlt;0.05). The averagehealing time of the fractures was 22.5 weeks in reamed group and 19 weeks in nonreamed group, and there was no significant difference between them (Ｐ＞0.05). Delayed unions occurred in 8 cases and 3 cases in reamed group and nonreamed group respectively. Conclusion Compared with reamed group, nonreamed intramedullary interlocking nails have lowerinfection rate and fewer delayed unions and ununions.
Objective To study the time effect of the gene expression of recombinant adeno-associated virus (rAAV) vector co-expressing human vascular endothel ial growth factor 165 (hVEGF165) and human bone morphogenetic protein 7 (hBMP-7) genes so as to lay a theoretical foundation for gene therapy of osteonecrosis. Methods The best multipl icity of infection (MOI) of BMSCs transfected with rAAV was detected by fluorescent cell counting. The 3rd generation rabbit bone mesenchymal stem cells (BMSCs) were transfected with rAAV-hVEGF165-internal ribosome entry site (IRES)-hBMP-7 (experimental group) and green fluorescent protein (GFP) labeled rAAV-IRES-GFP (control group), respectively. The expression of GFP was observed by inverted fluorescent microscope. The expressions of hVEGF165 and hBMP-7 were assessed by RT-PCR assay and Western blot assay in vitro. The transfected cells in 2 groups were prepared into suspension with 5 × 106 cells/mL, and injected into the rabbit thigh muscles of experimental group 1 (n=9) and control group 1 (n=9), respectively. The muscle injected with rAAV-IRES-GFP was sl iced by frozen section method and the expression of GFP protein was observed by inverted fluorescent microscope. The expressions of hVEGF165 and hBMP-7 were assessed by Western blot assay and ELISA assay in vivo. Results The best MOI of BMSCs transfected with rAAV was 5 × 104 v.g/cell. In vitro, the expressions of GFP, hVEGF165, and hBMP-7 genes started at 1 day after transfection, the expressions obviously increased at 14 days after transfection, and the expression maintained the b level at 28 days after transfection. In vivo, the expressions of GFP, hVEGF165, and hBMP-7 genes could be detected at 2 weeks after injection, and b expressions were shown at 6 to 8 weeks after injection. The values of hVEGF165 and hBMP-7 were (248.67 ± 75.58) pg/mL and (4.80 ± 0.61) ng/mL respectively in experimental group 1, and were (32.28 ± 8.42) pg/mL and (0.64 ± 0.42) ng/mL respectively in control group 1; showing significant differences between 2 groups (P lt; 0.05). Conclusion The rAAV-hVEGF165-IRES-hBMP-7 has efficient gene expression ability.