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Objective:To prepare the hydrogel scaffolds with different concentrations of laponite and compare their osteogenic properties.Methods:The scaffolds of gelatin/sodium alginate hydrogel into which laponite was added according to the mass ratios of 0%, 1%, 2%, and 3% were assigned into groups T0, T1, T2, and T3. In each group, the compressive modulus was measured and the leaching solution for 24 h extracted to measure the ion release. Bone marrow mesenchymal stem cells (BMSCs) were cultured in the extract medium from each group and common medium (blank group) ( n=3) in the in vitro experiments to determine the expression of osteogenic genes Runt-related transcription factor 2 (Runx2), alkaline phosphatase (ALP) and type I collagen after 7 days of culture. In the in vivo experiments, the scaffolds were implanted into the femoral condyle defects in rats, and a blank group with no scaffolds was set. The bone repair in each group was evaluated by hematoxylin-eosin(HE) staining and immunohistochemical staining. Results:The compressive modulus in group T2 [(139.05±6.43) kPa] was significantly higher than that in groups T0, T1 and T3 [(68.83±3.76) kPa, (101.18±3.68) kPa and (125.40±3.28) kPa] ( P<0.05). The ion contents of lithium, magnesium and silicon released from the 24 h leaching solution in group T2 were (0.031±0.005) μg/mL, (3.047±0.551) μg/mL and (5.243±0.785) μg/mL, insignificantly different from those in group T3 ( P> 0.05) but significantly larger than those in group T1 ( P>0.05). The in vitro experiments showed that the expression levels of Runx2, ALP and type I collagen in group T2 were 1.59±0.11, 2.02±0.08 and 1.06±0.17, significantly higher than those in the other groups ( P<0.05). HE staining showed that the implanted hydrogel was tightly bound to the bone tissue. Immunohistochemical staining showed that the numbers of Runx2 and osteocalcin positive cells in group T2 were significantly higher than those in the other groups. Conclusions:With ideal biocompatibility, hydrogel scaffolds with different concentrations of laponite can slowly release the decomposed ions of lithium, magnesium and silicon to promote the osteogenic differentiation of BMSCs and the repair of bone defects in vivo. A 2% concentration of laponite in the hydrogel scaffolds may result in the best results.
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Development and application of stem cells and their related technologies have paved new ways for prevention and treatment of orthopedic diseases. Application of stem cells for clinical treatment of bone defects is extremely promising, fracture, nonunion and osteonecrosis of the femoral head (ONFH) in particular. However, promotion of clinical stem cell therapy still faces difficulties and lacks corresponding standards. This article reviews clinical researches on stem cell therapy for bone injury and summarizes the injury types, cell types, cell numbers and their clinical efficacy, hoping to provide references for clinical treatment of bone injury with stem cells.
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Objective:To prepare biomimetic tissue engineering scaffolds of gelatin/sodium alginate/laponite composite hydrogel loaded with BMSCs by 3D biological printing technique，and explore the osteogenic effect of 3D printing on hydrogel scaffolds containing bone marrow mesenchymal stem cells（BMSCs）.Methods:BMSCs were routinely extracted and identified by flow cytometry. Gelatin，sodium alginate and laponite were mixed and then BMSCs were added to prepare cell-containing composite hydrogel scaffolds using 3D bioprinting. Non-printed scaffolds containing cells were prepared by injection molding method. In vitro，the prepared scaffolds were divided into the printing group with cells and non-printing group with cells according to whether they were printed，with 12 samples per group. Another simple cell culture group was set as control. Then，the internal structure of the composite hydrogel was observed by scanning electron microscope，and the expansion rate and water content of the scaffolds were measured by freeze-drying method. At day 3 after culture，the growth status of BMSCs was observed by phalloidine staining. cell counting kit（CCK）-8 assay was used to detect cell activity in scaffolds at days 1，3，and 7 after culture and RT-PCR to detect the expression of osteogenesis related genes Osterix，osteocalcin（OCN）and collagen I at days 7 and 14 ofter culture. In vivo，four groups were set according to printing or not and whether containing cells or not：printing implant group with cells，non-printing implant group with cells，printing implant group without cells and non-printing implant group without cells，with 9 samples per group. Scaffolds in four groups were implanted to the posterior gluteal muscle pouches（random on left or right）of 36 8-week-old SD rats，respectively. The samples were taken X-ray images at 2，4 and 8 weeks after operation，respectively. The osteogenic differentiation of tissues at 8 weeks was observed by HE and Masson staining. Results:The flow cytometry showed that the cells were BMSCs. Internal pores of hydrogels were obvious，and cells stretched freely in the pores. Differences of the swelling rate and water content were not statistically significant between printing group with cells［（1，039.37±30.66）%，（91.21±0.26）%］and non-printing group with cells［（1，032.38±35.05）%，（91.16±0.28）%］（ P>0.05）. At day 3 after culture in vitro，the cells grew well in the hydrogel. After culturing for 1 day in vitro，there was no significant difference in absorbance between printing group with cells and non-printing group with cells（ P>0.05）. At day 3 after culture，there was no significant difference in absorbance between printing group with cells and non-printing group with cells，but both groups showed a higher level than simple cell culture group（ P<0.05）. At day 7 after culture，the absorbance in printing group with cells（2.72±0.17）was higher than that in non-printing group with cells（2.35±0.11），and both of which were higher than that in simple cell culture group（1.95±0.12）（ P<0.05）. At day 7 after culture in vitro，there was no statistically significant difference in the expression of osteogenic differentiation-related genes between printing group with cells and the non-printing group with cells（ P>0.05），but they were all higher than those in simple cell culture group（ P<0.05）. At day 14 after culture in vitro，the expression of osteogenesis-related genes Osterix（1.650±0.095），OCN（2.725±0.091），collagen I（2.024±0.091）in printing group with cells were higher than those in non-printing group with cells（1.369±0.114，2.174±0.198，1.617±0.082，respectively）and those in simple cell culture group（1.031±0.094，1.116±0.092，0.736±0.140，respectively）（ P<0.05）. After implantation for 2 weeks in vivo，with no statistically significant difference in the gray values of X-ray films in each group（ P>0.05）. At weeks 4 and 8 after implantation，the gray values of X-ray films in printing implant group with cells and non-printing implant group with cells were higher than those in printing implant group without cells and non-printing implant group without cells（ P<0.01）. At 8 weeks after implantation，HE staining showed that the scaffolds were degraded in different degrees and immersed with cells，with collagen production seen in Masson staining as well. Conclusions:Composite hydrogel scaffolds can provide a good three-dimensional environment for BMSCs growth. 3D bioprinting can promote the proliferation and osteogenic differentiation of BMSCs in hydrogel scaffolds. In addition，BMSCs-loaded scaffolds can be degraded slowly in vivo with good ectopic osteogenic ability.
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Objective:To characterize the biological activity of fibroblasts on the surface of titanium alloy sheets with different ridge widths by investigating the effects of ridge widths on the adhesion, proliferation and differentiation of fibroblasts.Methods:Five groups of titanium sheets with ridge widths of 50 μm, 80 μm, 100 μm, 150 μm and 200 μm were prepared, with all the groove depths being 10 μm. The titanium sheets with no ridges were taken as a control group. After fibroblasts were incubated on the sheets, states of their adhesion were observed by scanning electron microscopy (SEM) at different time points. CCK-8 cell proliferation test and immunofluorescence staining were used to observe proliferation and shape of the cells. The effects of ridge widths on adhesion of fibroblasts were evaluated by Vinculin immunofluorescence staining, and the effects of ridge widths on expression of α-smooth muscle actin ( α-SMA) by immunofluorescence. Results:SEM showed that the cells adhered to the ridges on the titanium sheets 48 hours after inoculation. In the groups with smaller ridge widths (from 50 μm to 150 μm), the cells were slender in shape and grew along the ridge direction. CCK-8 indicated that different ridge widths had no significant effect on the proliferation of fibroblasts between the 6 groups ( P>0.05). Immunofluorescence staining showed that the cells arranged in an orderly direction along the ridges; the long axis of the cells in the 50 μm group showed the best consistency with the extending direction of the ridge, with significant differences among the 6 groups ( P<0.05). The Vinculin test found that the secretion of cell adhesion protein was concentrated in the ridge and semi-quantitative analysis showed that the 50 μm group had the most Vinculin secretion, with significant differences among the 6 groups ( P<0.05). The α-SMA test showed that the ridge width had a regulatory effect on the myogenic differentiation of fibroblasts, and the 50 μm group had the strongest expression of α-SMA, with significant differences among the 6 groups ( P<0.05). Conclusions:Modification of ridges on the surface of titanium sheets may affect arrangement, adhesion and myogenic differentiation of fibroblasts. The ridges of 50 μm in width may lead to stronger polarized arrangement of fibroblasts, more secretion of adhesion-related protein and more pronounced myogenic differentiation of fibroblasts.
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Objective:To explore the significance of digital orthopedic technology in surgical plan for spinal tumor and the preliminary outcomes of 3D printed vertebral bodies in spinal tumor surgery.Methods:The clinical data of 2 patients were retrospectively analyzed who had had a 3D printed vertebral body implanted at Center of Orthopaedics, Shenzhen Hospital from June 2018 to December 2019. One was a 32-year-old male, diagnosed with cervical neurinoma; the other was a 27-year-old female, diagnosed with giant cell tumor of lumbar bone. 3D virtual reconstruction of tumor and surrounding structures was established via Mimics software for surgical plan. Virtual osteotomy was simulated, their disease models and guide templates were 3D printed, and their metal artificial vertebral bodies were 3D printed after personalized design of the vertebral body diameter, porosity and procedures of reconstruction and fixation. Lesion resection and prosthesis implantation were carried out in accordance with the preoperative plan. After operation, the motor function of cervical or lumbar vertebrae, tumor recurrence, and spinal stability reconstructed were regularly observed.Results:Resections and reconstructions went uneventfully in both cases. The 2 patients were followed up for 21 and 13 months respectively. Their postoperative images showed that their 3D printed vertebral bodies fitted the neighboring vertebral bodies well. The spinal stability was reconstructed without any loosening or periprosthetic osteolysis, and the tumors were removed completely with no recurrence in both cases. Their spinal motor function was satisfactory.Conclusions:Digital orthopedic technology can offer accurate guidance in the treatment of spinal tumors. It is necessary to consider local physiological anatomy in personalized design of a metal vertebral body 3D printed. Clinical application of 3D printed metal vertebral bodies is a new strategy for spinal reconstruction following spinal tumor resection.
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Objective@#To evaluate the effect of 3DBody software assisted problem-based learning (PBL) teaching in orthopedic teaching.@*Methods@#Undergraduates of clinical medicine from grade 2013 who had internship in our hospital were divided into experimental group and control group. Undergraduates in the experimental group were taught by 3DBody software assisted PBL teaching, with designed questions and the method of using 3DBody software handing to students before class. While undergraduates in the control group were taught by traditional teaching, with the use of textbooks and multimedia courseware. Examination scores of theory and probation were compared between the two groups. Questionnaires were used to evaluate the subjective perception of different teaching method among the participants in each group.@*Results@#Scores of theoretical examination in the experimental group (84.6±5.9) were higher than those in the control group (73.2±6.1); scores of probation examination in the experimental group (17.7±2.1) were significantly higher than those in the control group (12.7±1.9); the degree of satisfaction in the experimental group (9.2±0.8) was significantly higher than that in the control group (7.2±1.3); all differences were statistically significant (P<0.05).@*Conclusion@#3DBody software assisted PBL teaching can significantly improve the effectiveness of orthopedic teaching and enhance students' learning initiative and interest, which is worth promoting.
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Objective@#To compare the biomechanical performance between the single- versus double-threaded cannulated screws in the treatment of femoral neck fractures of Pauwels type Ⅲ.@*Methods@#Models of femoral neck fracture of Pauwels type Ⅲ (70°) were made of the Sawbone synthetic composite femurs. All specimens were divided into 2 groups (n=12). Group A was fixated with single-threaded cannulated screws and group B with double-threaded cannulated screws, both in an inverted triangle configuration. The screws ranged from 90 to 95 mm in length and from 7.3 to 7.5 mm in diameter. All the specimens were subjected to axial stiffness and failure load tests with 7° valgus (simulating normal two-legged weight-bearing stance) and 25° valgus (simulating normal one-legged weight-bearing stance) and torsion test as well. The 2 groups were compared in the torques at axial stiffness angles of 1°, 2°, 3°, 5° and 7°.@*Results@#Group B had significantly greater axial stiffness at 7° valgus and 25° valgus (89±26 N/mm and 128±37 N/mm) and failure load (1,154±368 N) than group A did (36±12 N/mm and 47±16 N/mm; 688±94 N) (P< 0.05). The torques increased with the increase in rotation angle in both groups. However, the torques in group B (3.26±0.96, 4.16±1.23, 4.64±1.13, 5.59±1.26 and 6.53±1.47 N·m) were all significantly larger than in group A (1.44±0.19, 2.03±0.41, 2.33±0.62, 2.74±0.87 and 3.05±1.07 N·m) (P<0.05).@*Conclusion@#Double-threaded cannulated screws may provide better biomechanical stability than single-threaded ones, due to their substantial improvement in anti-compression and anti-rotation performance.
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Objective@#To establish an efficient classification and treatment system for limb long bone defects.@*Methods@#Based on the length of bone defect, soft tissue injury and wound infection, a new classification and treatment system was proposed with reference to Gustilo-Anderson classification for open fractures and Orthopedic Trauma Association (OTA) classification.@*Results@#We divided the limb long bone defects into 3 types, each of which was subdivided into 4 subtypes depending on concomitant soft tissue defect and/or infection. Type Ⅰ are bone defects less than 4 cm in length, including type Ⅰa (simple bone defects with a limited extent), type Ⅰb (bone and soft tissue defects), type Ⅰc (bone defects with infection) and type Ⅰd (bone defects with infection and soft tissue defects). Type Ⅱ are bone defects ranging from 4 to 10 cm in length, including type Ⅱa (simple bone defects with a large extent), type Ⅱb (bone and soft tissue defects), type Ⅱc (bone defects with infection) and type Ⅱd (bone defects with infection and soft tissue defects). Type Ⅲ are bone defects larger than 10 cm in length, including type Ⅲa (simple bone defects with a very large extent), type Ⅲb (bone and soft tissue defects), type Ⅲc (bone defects with infection) and type Ⅲd (bone defects with infection and soft tissue defects).@*Conclusion@#Our new classification and treatment system for long limb bone defects is more efficient and intuitive, facilitating clinical diagnosis and treatment of limb long bone defects.
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Objective To compare the biomechanical performance between the single-versus double-threaded cannulated screws in the treatment of femoral neck fractures of Pauwels type Ⅲ.Methods Models of femoral neck fracture of Pauwels type Ⅲ (70°) were made of the Sawbone synthetic composite femurs.All specimens were divided into 2 groups (n =12).Group A was fixated with single-threaded cannulated screws and group B with double-threaded cannulated screws,both in an inverted triangle configuration.The screws ranged from 90 to 95 mm in length and from 7.3 to 7.5 mm in diameter.All the specimens were subjected to axial stiffness and failure load tests with 7° valgus (simulating normal two-legged weight-bearing stance) and 25° valgus (simulating normal one-legged weight-bearing stance) and torsion test as well.The 2 groups were compared in the torques at axial stiffness angles of 1°,2°,3°,5° and 7°.Results Group B had significantly greater axial stiffness at 7° valgus and 25° valgus (89 ± 26 N/mm and 128 ± 37 N/mm) and failure load (1,154 ±368 N) than groupAdid (36 ±12 N/mm and 47 ±16 N/mm;688 ±94 N) (P ＜0.05).The torques increased with the increase in rotation angle in both groups.However,the torques in groupB (3.26±0.96,4.16±1.23,4.64±1.13,5.59±l.26and6.53±l.47 N·m) were all significantly larger than in group A (1.44 ±0.19,2.03 ±0.41,2.33 ±0.62,2.74 ±0.87 and 3.05 ± 1.07 N · m)(P ＜ 0.05).Conclusion Double-threaded cannulated screws may provide better biomechanical stability than single-threaded ones,due to their substantial improvement in anti-compression and anti-rotation performance.
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Objective To establish an efficient classification and treatment system for limb long bone defects.Methods Based on the length of bone defect,soft tissue injury and wound infection,a new classification and treatment system was proposed with reference to Gustilo-Anderson classification for open fractures and Orthopedic Trauma Association (OTA) classification.Results We divided the limb long bone defects into 3 types,each of which was subdivided into 4 subtypes depending on concomitant soft tissue defect and/or infection.Type Ⅰ are bone defects less than 4 cm in length,including type Ⅰa (simple bone defects with a limited extent),type Ⅰb (bone and soft tissue defects),type Ⅰc (bone defects with infection)and type Ⅰd (bone defects with infection and soft tissue defects).Type Ⅱ are bone defects ranging from 4 to 10 cm in length,including type Ⅱa (simple bone defects with a large extent),type Ⅱb (bone and soft tissue defects),type Ⅱc (bone defects with infection) and type Ⅱd (bone defects with infection and soft tissue defects).Type Ⅲ are bone defects larger than 10 cm in length,including type Ⅲa (simple bone defects with a very large extent),type Ⅲb (bone and soft tissue defects),type Ⅲc (bone defects with infection) and type Ⅲ d (bone defects with infection and soft tissue defects).Conclusion Our new classification and treatment system for long limb bone defects is more efficient and intuitive,facilitating clinical diagnosis and treatment of limb long bone defects.
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Objective To evaluate the effect of 3DBody software assisted problem-based learning (PBL) teaching in orthopedic teaching. Methods Undergraduates of clinical medicine from grade 2013 who had internship in our hospital were divided into experimental group and control group. Undergraduates in the experimental group were taught by 3DBody software assisted PBL teaching, with designed questions and the method of using 3DBody software handing to students before class. While undergraduates in the control group were taught by traditional teaching, with the use of textbooks and multimedia courseware. Examination scores of theory and probation were compared between the two groups. Questionnaires were used to evaluate the subjective perception of different teaching method among the participants in each group. Results Scores of theoretical examination in the experimental group (84.6 ±5.9) were higher than those in the control group (73.2 ±6.1); scores of probation examination in the experimental group (17.7 ± 2.1) were significantly higher than those in the control group (12.7 ±1.9); the degree of satisfaction in the experimental group (9.2 ±0.8) was significantly higher than that in the control group (7.2 ±1.3); all differences were statistically significant (P<0.05). Conclusion 3DBody software assisted PBL teaching can significantly improve the effectiveness of orthopedic teaching and enhance students' learning initiative and interest, which is worth promoting.
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Objective To systematically evaluate the biomechanical recovery of drilled holes in the femur in SD rats.Methods Eighteen female SD rats were randomized into 3 even groups (n =6).Models of 2-mm drilled holes in bilateral femurs were established in groups A and B with 2 holes on each side while no drilling was performed in group C.Samples were harvested in group A at postoperative 4 weeks,in group B at postoperative 8 weeks while at both 4 and 8 weeks in group C.The samples were evaluated in terms of linear elasticity (compression test),viscoelasticity (relaxation and creep tests) and durability (fatigue failure test).Micro-CT scan was performed to measure the bone volume fraction (BV/TV) and bone mineral density (BMD) of new bone.Sirus red staining was performed to measure regeneration of type Ⅰ collagen of new bone.Results The elasticity modulus,maximum load,compression strength and conditional yield limit in groups A were significantly lower than those in group B which were also significantly lower than those in group C (P ＜ 0.05).At 7,200 s,the relaxation (14.56 ±0.69 MPa) and creep variation (11.37％ ± 0.70％) in group A were significantly higher than those in group B (11.06 0.63 MPa and 8.98％ ± 0.40％) which were also significantly higher than those in group C (6.99 ±0.56 MPa and 5.10％ ±0.23％) (P ＜ 0.05).At the constant amplitude loads from 20 N to 200 N,from 20 N to 300 N and from 20 N to 400 N,the recycling numbers in group A (6,044.3 ±879.7,4,093.3 ±628.5 and 1,919.3 ±847.5) were significantly lower than those in group B (10,192.3 ± 1,109.1,6,750.6 ± 818.0 and 3,376.6 ± 671.3) which were also significantly lower than those in group C (28,068.3 ±2,702.6,11,788.3 ± 1,141.6 and 5,296.3 ± 735.0) (P ＜ 0.05).By micro-CT scan,the BVT and BMD in group A were significantly lower than those in group B which were also significantly lower than those in group C (P ＜ 0.05).The sirus red staining showed the type Ⅰ collagen in the bone defect area was completely regenerated in group B.Conclusion Systematic biomechanical measurements may actually detect the characteristics of biomechanical recovery of bone holes in SD rats,enriching the basic research on the bone damage repairing progress.
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Objective To compare the effectiveness of expandable intramedullary nail(EIMN) versus locked compression plate (LCP) in the treatment of humeral shaft fractures of AO types A and B.Methods The clinical data were retrospectively analyzed and compared of the 44 humeral shaft fractures which had been treated between May 2012 and February 2016.There were 26 men and 18 women,from 23 to 66 years of age (average,41.5 years).By AO classification,22 cases were type 12-A and 22 type 12-B.EINM was used in 22 patients with an average age of 41.3 ± 1 1.7 years and LCP in 22 ones with an average age of 41.6 ± 10.3 years.The 2 groups were compared in terms of intraoperative blood loss,operative time,hospital stay,union time,union rate,Constant and Mayo scores at the final follow-ups,and complications as well.Results The 2 groups were compatible without significant differences in the preoperative demographic data (P ＞ 0.05).All the 44 patients were followed up for 10 to 18 months (average,12 months).The intraoperative blood loss (76.4 ± 18.66 mL),operative time (69.1 ± 13.2 min),incision length (5.8 ± 1.5 cm) and union time (13.2 ± 8.4 w) in the EIMN group were significantly better than those in the LCP group (138.6 ± 39.4 mL,96.4 ± 14.2 min,8.5 ± 1.4 cm and 18.4 ± 6.6 w,respectively) (P ＜ 0.05).There was also a significant difference between the 2 groups in the total complication rate[18.2％ (4/22) versus 50.0％ (11/22)] (P ＜0.05).No deep infection or should pain was observed in either group.Conclusions Inthe treatment of humeral shaft fractures of AO types 42-A and 42-B,compared with LCP,EIMN may have advantages of less intraoperative blood loss,operative time,union time and complications.The 2 methods are similar in hospital stay and final functional recovery of the should joint.
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Objective To compare patellar ring,Kirschner wire tension band and patellar ring plus Kirschner wire in fixation for treatment of patella fractures.Methods A retrospective analysis was conducted on the 285 patients with patellar fracture who had been treated between September 2009 and January 2016.They were 155 men and 130 women,with an average age of 45.5 years (from 18 to 70 years).Their fractures included 176 transverse,28 longitudinal split and 81 comminuted ones.They were divided into 3 groups according to their different internal fixation methods:patellar ring fixation (98 cases),Kirschner wire tension band (92 cases),patellar ring plus Kirschner wire fixation (95 cases).The 3 groups were compared in terms of operative time,intraoperative bleeding,fracture healing time,knee function by B(o)stman score at the last follow-up and postoperative complications.Results The operative time in the patellar ring group(58.9 ±6.4 min) was significantly shorter than in the Kirschner wire group (71.8 ± 7.8 min) and in the patellar ring plus Kirschner wire group (74.4 ± 8.0 min) (P ＜ 0.05).There were no statistical significant differences between the 3 groups in fracture healing time and intraoperative bleeding (P ＞ 0.05).The good to excellent rate of knee function at the last follow-up in the Kirschner wire tension band group was 100.0％ (92/92),significantly higher than in the patellar ring group (90.8％,89/98) and in the patellar ring plus Kirschner wire group (91.6％,87/95) (P ＜ 0.017).There was no significant difference in postoperative complication rate between the patellar ring fixation group (2.0％,2/98),Kirschner wire tension band fixation group (1.1％,1/92) and the patellar ring plus Kirschner wire group (2.1％,2/95) (P ＞ 0.05).Conclusion Internal fixation with Kirschner wire tension band has definite curative effect on patellar fractures,showing the advantages of less operative invasion,fewer postoperative complications,better functional recovery of the affected knee joint,and lower price over the other 2 internal fixation methods.
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Objective To prepare biphasic calcium phosphate/polyvinyl alcohol scaffolds by 3D printing at room temperature and explore the effect of 3D scaffolds on in vitro osteogenic differentiation of the bone marrow mesenchymal stem cells (BMSCs).Methods After biphasic calcium phosphate and polyvinyl alcohol solutions were mixed,the biphasic calcium phosphate/polyvinyl alcohol composite scaffolds were prepared by room temperature 3D printing combined with freeze drying technique.Non-printing scaffolds were prepared by injection molding.The surface microstructure,porosity,elastic modulus and hydrophilicity of the 2 sorts of scaffolds were measured.The cytological experiments were carried out in 3 groups (n =3):printed scaffold group,non-printed scaffold group and blank control group (no scaffold).After the BMSCs were seeded onto the scaffolds for 7 and 14 days,the 3 groups were compared in terms of cellular proliferation,alkaline phosphatase activity and expression levels of osteogenesis-related genes.Results 3D composite scaffolds with controllable pore size and porosity were prepared successfully,with an average porosity of 59.6％ ± 3.6％ and an average elastic modulus of 429.3 ± 54.3 kPa.After culture for 7 and 14 days,the cellular absorbance values in the printed scaffold group (0.987 ± 0.047 and 1.497 ± 0.076) were significantly higher than those in the non-printed scaffold group (0.767 ±0.063 and 1.181 ±0.098) (P ＜ 0.05) which were in turn significantly higher than those in the blank control group (0.532 ±0.046 and 0.895 ± 0.062) (P ＜ 0.05).After culture for 7 and 14 days,the ALP activity and expression levels of osteogenesis-related genes in the printed and non-printed scaffold groups showed no significant between-group differences (P ＞ 0.05),but were significantly higher than those in the blank control group (P ＜ 0.05).Conclusions Tissue-engineered composite biphasic calcium phosphate/polyvinyl alcohol scaffolds with controllable pore size and good connectivity can be prepared by freeze-drying and room temperature 3D printing techniques.Co-culture of the scaffolds and BMSCs in vitro promotes adhesion,proliferation and osteogenic differentiation of the cells.
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BACKGROUND: Neuropeptides, a kind of endogenous active substance in nerve tissues, can modulate physiological functions of multiple body systems.OBJECTIVE: To observe the effects of vascular bundles or sensory nerve tracts implanted into tissue-engineered bone for rabbit large bone defects on the expression levels of calcitonin gene-related peptide (CGRP) and neuropeptide-Y.METHODS: Fifty-four New Zealand rabbits were enrolled to make model of large bone defects, and then, the animal models were randomly divided into three groups, including sensory nerve tract, vascular bundle, and control groups (n=18 per group), followed by implanted with sensory nerve tracts, vascular bundle, and tissue-engineered bone without sensory tracts or vascular bundle, respectively. The defected bone received gross and Masson staining at 4, 8 and 12 weeks after modeling, to compare the expression levels of CGRP and neuropeptide-Y in each group.RESULTS AND CONCLUSION: mRNA expression levels of CGRP and neuropeptide-Y in the sensory nerve tract and vascular bundle groups were significantly higher than those in the control group at different time points after modeling (P < 0.05). mRNA expression levels of CGRP and neuropeptide-Y in the tissue-engineered bone began to be increased and peaked at the 8th week, and then decreased (P < 0.05), which were the lowest at the 4th week (P < 0.05).Immunohistochemical staining results showed that CGRP was mainly found in the bridge, periosteum of newly born bones and around blood vessels; while neuropeptide-Y mainly localized in the medullary cavity and around blood vessels. These results indicate that the implantation of vascular bundle and sensory nerve tracts for bone defects can upregulate the expression levels of CGRP and neuropeptide-Y, and promote bone repair. However, sensory tract implantation may cause sensory impairment; thereafter, vascular bundle implantation is more suitable for ideal tissue-engineered construction to meet physical requirements.
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BACKGROUND:Previous study has proved that implantation of the tissue-engineering bone with vascular bundles or sensory nerve tracts can promote bone formation, which may be related to the expression of sensory neuropeptide receptors. OBJECTIVE:To investigate the effect of implantation of tissue-engineered bone containing vascular bundles and sensory nerve tracts on the middle-and long-term expression of calcitonin gene-related peptide type Ⅰ receptor (CGRP1R) in the repair of rabbit large femoral defects. METHODS:Thirty-six New Zealand white rabbits were enrol ed and modeled into 1.5 cm femoral defects, and then randomized into three groups. Bone marrow mesenchymal stem cells (BMSCs) were subjected to osteoblastic induction for 7 days, and then seeded onto the β-calcium phosphate scaffold to construct the tissue-engineered scaffold.In sensory nerve group, the tissue-engineered scaffold was implanted into the defect region, and autologous sensory nerve bundles were implanted into the lateral groove of the tissue-engineered bone;in vascular bundle group, the tissue-engineered scaffold was implanted, and autologous femoral blood bundles were implanted into the lateral groove of the tissue-engineered bone;in blank control group, only the tissue-engineered scaffold was implanted. X-ray examination, immunohistochemistry and real-time PCR were performed at 24 and 48 weeks postoperatively. RESULTS AND CONCLUSION:The X-ray scores in the sensory nerve and vascular bundle groups were significantly higher than that in the control group (P<0.05), but no significant difference was found between sensory nerve and vascular bundle groups. Real-time PCR found that the expression level of CGRP1R mRNA in the vascular bundle group was significantly higher than that in the other two groups (P<0.05), but showed no significant difference between sensory nerve and blank control groups.Immunohistochemistry findings showed that CGRP1R positive expression rate in the sensory nerve and vascular bundle groups was higher than that in the blank control group. These results reveal that implantation of the tissue-engineered bone containing vascular bundles can promote the CGRP1R expression.
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Objective To investigate the effect of sensory and motor nerve homogenates at different concentrations on the proliferation and osteogenesis differentiation of bone marrow mesenchymal stem cells (BMSCs) in rats.Methods The saphenous nerve and the muscle branch of the sciatic nerve in rats were extracted surgically as sensory and motor nerve tissues,respectively.The primary nerve homogenates (10 mg/mL) were prepared as per 10 mg tissue with 1 mL osteoblast inducing conditional media,and 10 times diluted after filtration purification to prepare sensory and motor nerve homogenates at concentration gradients of 1.0,0.1,0.01,0.001 and 0.0001 mg/mL.Cultivation GFP ± rat pups BMSCs in vitro were trained to P3 generation.The experiment was carried out in 3 groups.The sensory and motor nerve homogenates of 500 μL at the above 6 concentration gradients were added during cultivation respectively in the sensory nerve group (n =18) and the motor nerve group(n =18) while 500 μL of osteoblast inducing conditional media was added in the control group(n =3).Cell proliferation quantity detection and alkaline phosphatase (ALP) staining were used to assess the proliferation and differentiation of BMSCs after 14 days.Results According to the results of CCK-8,the cellular absorbance values at concentrations of 1.0 and 0.1 mg/mL homogenate in the sensory nerve group (1.957 ±0.065 and 1.751±0.073) were significantly greater than in the control group (1.145±0.087) while the cellular absorbance value at concentration of 10.0 mg/mL homogenate in the motor nerve group (0.304 ± 0.619) was significandy smaller than in the control group (1.145 ± 0.087) (P ＜ 0.05).According to the ALP staining,the amounts of cellular calcium nodules in the sensory and motor nerve groups (2.667 ± 0.816 and 3.000 ± 0.632,respectively) were significantly smaller than in the control group (11.833 ± 1.471) (P ＜ 0.05).Conclusion Sensory nerve homogenate is different from motor nerve homogenate in that it may promote proliferation of BMSCs and inhibit osteogenesis differentiation of BMSCs in a certain rage of concentrations.
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Objective To evaluate the safety of Renaissance spine robot assisted system in spinal injury.Methods From March 2014 to May 2016,38 patients with spinal disease received spinal surgery assisted by spine robot system.They were 20 males and 18 females,with an average age of 42 years (range,from 12 to 69 years).There were 10 lumbar fractures,8 thoracic fractures and 20 spinal deformities.Pedicle screw implantation was conducted in 30 patients (PS group) and percutaneous vertebroplasty in 8 (PV group).One side was chosen randomly to use Mazor spine robot assisted system (assisted group) and the opposite side the conventional method (non-assisted group).The anteroposterior and lateral X-rays and CT scan of the lumbar and/or thoracic spine were performed in all patients after surgery.The precision of pedicle screws implantation in PS group was evaluated by the Abul-Kasimhierarchy grading system;location of the puncture trajectory,time used for puncture and radiation exposure time in PV group were evaluated.Results 208 pedicle screws were implanted in PS group,including 120 lumbar ones and 88 thoracic ones.For lumbar pedicle screw implantation,the excellent to good rate was 95.0％ (57/60) in the assisted group,significantly higher than that in the non-assisted group (80.0％,48/60) (P ＜ 0.05).For thoracic pedicle screw implantation,the excellent to good rate was 95.5％ (42/44) in the assisted group,significantly higher than that in the non-assisted group (77.3％,34/44) (P ＜ 0.05).There were 24 puncture trajectories in 8 patients in PV group,showing no pedicle penetration or cement leaking in any case.The mean time used for puncture was 5.5 ± 1.4 min in the assisted group,significantly shorter than that in the non-assisted group (17.8 ± 7.5 min) (P ＜ 0.05);the X-ray exposure time was 14.0 ± 4.0 s in the assisted group,significantly shorter than that in the non-assisted group (22.4 ± 6.0 s) (P ＜ 0.05).Conclusions Renaissance spine robot-assisted system deserves more clinical application,because in spinal surgery it can make pedicle screw implantation more precise and safer,and can reduce operation time and X-ray exposure time in percutaneous vertebroplasty.
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Objective To investigate the effect of prevascularized tissue-engineered bone graft on regeneration of femoral bone defects in rats.Methods Models of femoral bone defect were created at the bilateral hind limbs of 20 healthy female 10 week-old rats which were divided into 2 even groups randomly (n =10).In group A,conventional tissue-engineered bone grafts were transplanted into the femoral bone defects;in group B,tissue-engineered bone grafts and vascular bundles were implanted into the femoral defects.At 1,4 and 8 weeks after operation,3 rats were sacrificed each time in each group to harvest samples.The remaining one in each group served as a spare animal.Regeneration of bone defects and degradation of scaffolds were assessed by radiologic modality and hematein eosin staining.Results At week 1,the new bone ratio (BV/TV) was 5.47％ ± 1.90％ in group A and 8.49％ ± 1.26％ in group B,showing no significant difference (P ＞ 0.05);at weeks 4 & 8,the BV/TV were 17.54％ ±2.04％ and 39.73％ ± 4.01％ in group A,significantly lower than those in group B (25.32％ ± 2.15％ and 53.22％ ± 2.94％) (P ＜ 0.05).At weeks 1 & 4,the scaffold degradation ratios (RSV/SV) were 97.33％ ± 2.52％ and 80.60％ ±4.00％,showing no significant differences from those in group B (95.67％ ±3.51％ and 75.22％ ±6.20％) (P ＞ 0.05).At week 8,the scaffold degradation ratio in group A (65.46％ ±4.51％) was significantly higher than that in group B (50.19％ ±4.91％) (P ＜ 0.05).At week 8,hematein eosin staining showed better integration of scaffolds with the femur,faster degradation of the interior scaffolds and greater osteogenetic activity in group B.Conclusion Prevascularization of tissue-engineered bone graft may increase new bone volume and scaffold degradation rate,promoting repair of femoral bone defects in rats.