In clinical settings,tantalum(Ta)is extensively implemented as a bone implant material.Ta is highly stable and biocompatible in vivo,being one of the metallic biomaterials having high affinity for bone tissue.However,...In clinical settings,tantalum(Ta)is extensively implemented as a bone implant material.Ta is highly stable and biocompatible in vivo,being one of the metallic biomaterials having high affinity for bone tissue.However,since Ta is a refractory metal,its application as bone implant material is limited.Most recently,additive manufacturing technology has introduced a novel approach to producing Ta implants.The present study compared the microstructure,surface and mechanical characteristics,and in vitro and in vivo biological characteristics of selective laser melted Ta(SLM Ta),selective laser melted titanium alloy Ti6Al4V with Ta coating(SLM Ti6Al4V with Ta coating),and selective laser melted Ti6Al4V(SLM Ti6Al4V).Results indicate that SLM Ta possesses superior mechanical characteristics contrasted with SLM Ti6Al4V and SLM Ti6Al4V with Ta coating.Furthermore,SLM Ta has anti-inflammatory activity,excellent osseointegration performance,and osteogenic bioactivity.We fabricated an SLM porous Ta bone plate and employed it for internal fixation of ulnar and radius fractures,which has been known to promote fracture healing.Further,the SLM porous Ta bone plate could form an integrated bone plate structure with the bone tissue at the implant site.Afterward,the porous structure of the plate minimizes its elastic modulus and eliminates stress shielding,leaving no need for further surgical removal.In conclusion,the SLM porous Ta bone plate meets the performance requirements(stimulating bone regeneration,non-stress shelter,and no need for second surgery)of an ideal bone plate and may revolutionize the field of internal fixation bone plates for fractures.展开更多
Fracture healing progress monitoring techniques attract global research attention due to the importance of selecting the timing of removing the fixation device.To this end,in this research,we present a piezoelectric-b...Fracture healing progress monitoring techniques attract global research attention due to the importance of selecting the timing of removing the fixation device.To this end,in this research,we present a piezoelectric-based smart internal fixation device,in which a piezoelectric sandwich structure is laminated to the surface of a bone plate.In the content,we explain the reasons for utilizing piezoelectric films,elaborate the mechanism of fracture monitoring,and introduce the mechanical parameters of the sensor.The simulation and experimental results show that the electrical output of the device is associated with the elastic modulus of the filler between the tested broken bones when the working load is maintained,indicating that the bone recovery progress could be successfully detected by the developed technique.展开更多
The purpose of this study was to observe the clinical efficacy of umbilical cord in the treatment of Jinri capsule and analyze its effect on postoperative injury and bone metabolism. Methods 90 cases of SAP tree fract...The purpose of this study was to observe the clinical efficacy of umbilical cord in the treatment of Jinri capsule and analyze its effect on postoperative injury and bone metabolism. Methods 90 cases of SAP tree fracture were randomly divided into two groups according to 1:1. In the control group, 45 patients were treated with MIPO, and 45 patients were treated with Jintian capsule based on MIPO for 6 weeks. Organic volume content (VOC), bone mass number (TB.n), elastic bone stress (ES) and calcium (BFP) were compared according to bone volume ratio (BV/TV) before and 6 weeks after operation. Six months postoperatively, bone protective function (OPG), tartrate phosphatase (TRAP), K collagen (KTH) and shoulder recovery were observed. Results Within 6 weeks after treatment, bone quality indexes such as TV were significantly lower than those in control group (P<0.05), and bone quality indexes such as VOC and TBC were significantly lower than those in control group (P<0.05). Significantly lower than control group (P<0.05). N was significantly higher than that of control group (P<0.05). The osteogenesis rates of BGP and OPG were higher than those of the control group (P<0.05), and the osteogenesis rates of TRAP and CTX were significantly lower than those of the control group (P<0.05). Were compared between the two groups before and 6 weeks after operation. Six months after surgery, the observation group had better function recovery, and the constant Murley score was significantly higher than that of the control group. Conclusion MIPO combined with Jintiange capsule can significantly improve the function recovery effect of shoulder joint, effectively stabilize bone mass index, promote the formation of bone structure, quickly recover bone metabolism function, and finally achieve fracture healing. It is worthy of clinical application.展开更多
Bone plates play a vital role in bone fracture healing by providing the necessary mechanical fixation for fracture fragments through modulating biomechanical microenvironment adjacent to the fracture site.Good treatme...Bone plates play a vital role in bone fracture healing by providing the necessary mechanical fixation for fracture fragments through modulating biomechanical microenvironment adjacent to the fracture site.Good treatment effect has been achieved for fixation of bone fracture with conventional bone plates,which are made of stainless steel or titanium alloy.However,several limitations still exist with traditional bone plates including loosening and stress shielding due to significant difference in modulus between metal material and bone tissue that impairs optimal fracture healing.Additionally,due to demographic changes and non-physiological loading,the population suffering from refractory fractures,such as osteoporosis fractures and comminuted fractures,is increasing,which imposes a big challenge to traditional bone plates developed for normal bone fracture repair.Therefore,optimal fracture treatment with adequate fixation implants in terms of materials and design relevant to special conditions is desirable.In this review,the complex physiological process of bone healing is introduced,followed by reviewing the development of implant design and biomaterials for bone plates.Finally,we discuss recent development of hybrid bone plates that contains bioactive elements or factors for fracture healing enhancement as a promising direction.This includes biodegradable Mg-based alloy used for designing bone screw-plates that has been proven to be beneficial for fracture healing,an innovative development that attracts more and more attention.This paper also indicates that the tantalum bone plates with porous structure are also emerging as a new fracture internal fixation implants.The reduction of the stress shielding is verified to be useful to accelerate bone fracture healing.Potential application of biodegradable metals may also avoid a second operation for implant removal.Further developments in biometals and their design for orthopedic bone plates are expected to improve the treatment of bone fracture,especially the refractory fractures.展开更多
Metal plates have always been the gold standard in the clinic for internal fracture fixation due to their high strength advantages.However,high elastic modulus can cause stress shielding and lead to bone embrittlement...Metal plates have always been the gold standard in the clinic for internal fracture fixation due to their high strength advantages.However,high elastic modulus can cause stress shielding and lead to bone embrittlement.This study used an electron beam melting method to prepare personalized porous Ti6Al4V(pTi)bone plates.Then,chemical vapor deposition(CVD)technology coats tantalum(Ta)metal on the pTi bone plates.The prepared porous Ta-coated bone plate has an elastic modulus similar to cortical bone,and no stress shielding occurred.In vitro experiments showed that compared with pTi plates,Ta coating significantly enhances the attachment and proliferation of cells on the surface of the scaffold.To better evaluate the function of the Ta-coated bone plate,animal experiments were conducted using a coat tibia fracture model.Our results showed that the Ta-coated bone plate could effectively fix the fracture.Both imaging and histological analysis showed that the Ta-coated bone plate had prominent indirect binding of callus formation.Histological results showed that new bone grew at the interface and formed good osseointegration with the host bone.Therefore,this study provides an alternative to bio-functional Ta-coated bone plates with improved osseointegration and osteogenic functions for orthopaedic applications.展开更多
To study the change of the stress shielding rate of stress-relaxation plate in vivo and its influence on fracture healing. Methods: The diaphyses of bilateral tibias in 70 New Zealand rabbits were osteotomized and fix...To study the change of the stress shielding rate of stress-relaxation plate in vivo and its influence on fracture healing. Methods: The diaphyses of bilateral tibias in 70 New Zealand rabbits were osteotomized and fixed with stress-relaxation plates (SRP, the SRP group) and rigid plates (RP, the RP group), respectively. The fracture healing process in these 2 groups was investigated by radiography, light and polarized light microscopy and biomechanical test at 2 to 48 weeks postoperatively. Results: Early after fixation the stress shielding rate was about 70% in both groups. While in the SRP group the stress shielding rate decreased gradually as time passed, which was significantly lower than that of the RP group (P< 0.05 ) by the end of the 8th postoperative week, and stabilized at the level of about 27% at 36-48 weeks after fixation. Abundant external callus associated with the formation of cartilaginous callus could be observed in the SRP group at 2-4 weeks postoperatively. The transformation of the callus into the lamellar bone began at 8-12 weeks, the collagen gradually arranged in order, and the mechanical nature of the united bone was gradually strengthened, too. In the RP group, the external callus was scarce at the early stage of fracture healing, and the callus remodeling at the late stage of fracture healing was dominated by bone absorption. The ultimate bending strength (UBS) was only 57.95 % of that of the normal by 48 weeks. Conclusions: The decrease of the stress shielding rate of SRP in vivo was well interrelated with the time of fixation. The application of SRP could promote the callus formation and bone reconstruction thus to favor the recovery of the mechanical strength of the united bone.展开更多
BACKGROUND The epiphyseal growth plate is an important anatomical segment localized on the ends of a long bone.Despite the abovementioned atractive reasons for alendronate’s use,few data on the effect of alendronate ...BACKGROUND The epiphyseal growth plate is an important anatomical segment localized on the ends of a long bone.Despite the abovementioned atractive reasons for alendronate’s use,few data on the effect of alendronate during epiphyseal growth exist.AIM Verify the effect of alendronate on the growth epiphyseal plate,and compare its effect with the size of the femur during the double-staining of the immunolocalization of transforming growth factor-β1(TGF-β1)and bone morphogenetic protein-2(BMP2)in endochondral ossifing in specimens that have received alendronate.METHODS Forty newborn rats were randomly divided into two groups:a control group(were given applications of 1 mg/kg physiologic saline)and a group that received Alendronate(a dose of 2.5 mg/kg).These groups were then divided into two subgroups for euthanasia in two and 12 d of life.After euthanasia,the femurs were removed,and the femoral bones were measured linearly between the apex of the greater trochanter until the lower intercondylar midlle face to verify the probable bone growth between 3 and 12 d in control and alednroanto treated rats.Posteriorly,the surgical pieces were also sent to the histopathology laboratory to produce histological slides.The obtained slides were stained with hematoxylin and eosin to measure each of the cartilage zones in endochondral development.and other slides were immunohistochemically tested for anti-TGF-β1 and BMP-2 antibodies to investigate the immunolocalization of these proteins in the epiphyseal plaque area.RESULTS On the third day,some diferences between the control group and specimens treated with alendronate were verified.Macroscopiccaly,we found similarities in size between the femoral bones when we compared the control group with the specimens that received alendronate.On the 12^th day,the bone size of the mice receiving the drug was significantly smaller than those of the control group.These results coincide with changes in the TGF-β1 and BMP-2 expression.In the specimens that received alendronate,the TGF-β1 was expressed in some sites of trabecular bone that was neoformed,peripherally to the bone marrow area.The BMP-2 was also positive in proliferative chondrocytes and hypertrofic chondrocytes.On the 12^th day,all layers of chondrocytes exhibited positivity for BMP-2 in the specimens that received alendronate.In the interface between the trabecular bone and cartilage,an area of disorganized bone deposition was evident.Neoformed bone also appeared to be different at 12 d.In the control group,BMP-2 was positive in an intense area of bone trabeculae,whereas the alendronate-treated group showed TGF-β1 positive trabeculae and a greater bone area.CONCLUSION Alendronate alters the immunolocalization of TGF-β1 and BMP-2 simultaneously,a condition that changes the usual histological aspects of the cartilage zone and impairs epiphysis growth and femur growth.展开更多
The scanning electron microscope (SEM) results of bone interface of titanium-coated 317L plate screw are reported in this article. 317L plate screw had a rough surface composed of sprayed pure titanium which formed a ...The scanning electron microscope (SEM) results of bone interface of titanium-coated 317L plate screw are reported in this article. 317L plate screw had a rough surface composed of sprayed pure titanium which formed a bone/metal interface in biointegration after implanted into the mandible of dog. Though a bone/metal interface in osseointegration was also formed on the surface of uncoated 317L plate screw after implantation, a smal1 space was seen between the bone and surface of the screw, indicating that the tissue compatibility of titanium-coated 317L plate screw may be better than that of the non-coated screw.展开更多
AIM: To determine whether use of a precontoured olecranon plate provides adequate fixation to withstand supraphysiologic force in a comminuted olecranon fracture model.METHODS: Five samples of fourth generation compos...AIM: To determine whether use of a precontoured olecranon plate provides adequate fixation to withstand supraphysiologic force in a comminuted olecranon fracture model.METHODS: Five samples of fourth generation composite bones and five samples of fresh frozen human cadaveric left ulnae were utilized for this study. The cadaveric specimens underwent dual-energy X-ray absorptiometry(DEXA) scanning to quantify the bone quality. The composite and cadaveric bones were prepared by creating a comminuted olecranon fracture and fixed with a pre-contoured olecranon plate with locking screws. Construct stiffness and failure load were measured by subjecting specimens to cantilever bending moments until failure. Fracture site motion was measured with differential variable resistance transducer spanning the fracture. Statistical analysis was performed with two-tailed Mann-Whitney-U test with Monte Carlo Exact test.RESULTS: There was a significant difference in fixation stiffness and strength between the composite bones and human cadaver bones. Failure modes differed in cadaveric and composite specimens. The load to failure for the composite bones(n = 5) and human cadaver bones(n = 5) specimens were 10.67 nm(range 9.40-11.91 nm) and 13.05 nm(range 12.59-15.38 nm) respectively. This difference was statistically significant(P ? 0.007, 97% power). Median stiffness for composite bones and human cadaver bones specimens were 5.69 nm/mm(range 4.69-6.80 nm/mm) and 7.55 nm/mm(range 6.31-7.72 nm/mm). There was a significant difference for stiffness(P ? 0.033, 79% power) between composite bones and cadaveric bones. No correlation was found between the DEXA results and stiffness. All cadaveric specimens withstood the physiologic load anticipated postoperatively. Catastrophic failure occurred in all composite specimens. All failures resulted from composite bone failure at the distal screw site and not hardware failure. There were no catastrophic fracture failures in the cadaveric specimens. Failure of 4/5 cadaveric specimens was defined when a fracture gap of 2 mm was observed, but 1/5 cadaveric specimens failed due to a failure of the triceps mechanism. All failures occurred at forces greater than that expected in postoperative period prior to healing.CONCLUSION: The pre-contoured olecranon plate provides adequate fixation to withstand physiologic force in a composite bone and cadaveric comminuted olecranon fracture model.展开更多
The locking compression plates (LCP) are efficient tools in open reduction and internal fixation (ORIF), especially in osteoporotic bones. Two important factors of screw density and screw position can affect the funct...The locking compression plates (LCP) are efficient tools in open reduction and internal fixation (ORIF), especially in osteoporotic bones. Two important factors of screw density and screw position can affect the functionality of the bone plate. Several studies have assessed the influence of the screw configurations on the bone-plate stiffness, but the effects of screw positions on the interfragmentary strain, εIF of LCP construct have not been investigated yet. In this study, finite element method was used to investigate the influence of screws number and position on the interfragmentary strain of LCP-femur system for a mid-shaft fracture. Results of this study showed that by insertion of screws closer to the fracture site, εIF decreases by 2nd degree polynomial function versus screw position, but by adding the screws from the ends of the plate, or by moving and placing the screws towards the fracture site, the reduction of εIF will be linear. Results of this study were compared and are in agreement with some studies in the literature, even though their scope was mostly stability of the bone-implant system, whereas our scope was focused on the interfragmentary strain.展开更多
Acetabular component revision in the presence of severe bone loss is difficult for reconstructing an acetabular component in the anatomical hip center. Various treatment options are available, although often the aceta...Acetabular component revision in the presence of severe bone loss is difficult for reconstructing an acetabular component in the anatomical hip center. Various treatment options are available, although often the acetabular defect cannot be corrected with a single option alone. Precise assessment of the bone loss and a suitable combination of methods are needed. Here we report a case of multiple failures with impaction bone grafting reconstruction for an acetabular bone defect of American Academy of Orthopedic Surgeons classification type III. We finally reconstructed the acetabulum with three femoral head allografts and a Kerboull-type acetabular reinforcement device. The allograft was a casted, jet-type helmet-like shape. A year later the patient was able to walk without a cane and perform light agricultural work. Accurate evaluation of the acetabular bone loss and appropriate reconstruction is important.展开更多
基金supported by the National Natural Science Foundation of China(No.82172398)Liaoning Revitalization Talents Program(No.XLYC2203102).
文摘In clinical settings,tantalum(Ta)is extensively implemented as a bone implant material.Ta is highly stable and biocompatible in vivo,being one of the metallic biomaterials having high affinity for bone tissue.However,since Ta is a refractory metal,its application as bone implant material is limited.Most recently,additive manufacturing technology has introduced a novel approach to producing Ta implants.The present study compared the microstructure,surface and mechanical characteristics,and in vitro and in vivo biological characteristics of selective laser melted Ta(SLM Ta),selective laser melted titanium alloy Ti6Al4V with Ta coating(SLM Ti6Al4V with Ta coating),and selective laser melted Ti6Al4V(SLM Ti6Al4V).Results indicate that SLM Ta possesses superior mechanical characteristics contrasted with SLM Ti6Al4V and SLM Ti6Al4V with Ta coating.Furthermore,SLM Ta has anti-inflammatory activity,excellent osseointegration performance,and osteogenic bioactivity.We fabricated an SLM porous Ta bone plate and employed it for internal fixation of ulnar and radius fractures,which has been known to promote fracture healing.Further,the SLM porous Ta bone plate could form an integrated bone plate structure with the bone tissue at the implant site.Afterward,the porous structure of the plate minimizes its elastic modulus and eliminates stress shielding,leaving no need for further surgical removal.In conclusion,the SLM porous Ta bone plate meets the performance requirements(stimulating bone regeneration,non-stress shelter,and no need for second surgery)of an ideal bone plate and may revolutionize the field of internal fixation bone plates for fractures.
基金the National Natural Science Foundation of China(Nos.61803017 and 61827802)in part funded by the Beihang University(Nos.KG12090401 and ZG216S19C8)。
文摘Fracture healing progress monitoring techniques attract global research attention due to the importance of selecting the timing of removing the fixation device.To this end,in this research,we present a piezoelectric-based smart internal fixation device,in which a piezoelectric sandwich structure is laminated to the surface of a bone plate.In the content,we explain the reasons for utilizing piezoelectric films,elaborate the mechanism of fracture monitoring,and introduce the mechanical parameters of the sensor.The simulation and experimental results show that the electrical output of the device is associated with the elastic modulus of the filler between the tested broken bones when the working load is maintained,indicating that the bone recovery progress could be successfully detected by the developed technique.
文摘The purpose of this study was to observe the clinical efficacy of umbilical cord in the treatment of Jinri capsule and analyze its effect on postoperative injury and bone metabolism. Methods 90 cases of SAP tree fracture were randomly divided into two groups according to 1:1. In the control group, 45 patients were treated with MIPO, and 45 patients were treated with Jintian capsule based on MIPO for 6 weeks. Organic volume content (VOC), bone mass number (TB.n), elastic bone stress (ES) and calcium (BFP) were compared according to bone volume ratio (BV/TV) before and 6 weeks after operation. Six months postoperatively, bone protective function (OPG), tartrate phosphatase (TRAP), K collagen (KTH) and shoulder recovery were observed. Results Within 6 weeks after treatment, bone quality indexes such as TV were significantly lower than those in control group (P<0.05), and bone quality indexes such as VOC and TBC were significantly lower than those in control group (P<0.05). Significantly lower than control group (P<0.05). N was significantly higher than that of control group (P<0.05). The osteogenesis rates of BGP and OPG were higher than those of the control group (P<0.05), and the osteogenesis rates of TRAP and CTX were significantly lower than those of the control group (P<0.05). Were compared between the two groups before and 6 weeks after operation. Six months after surgery, the observation group had better function recovery, and the constant Murley score was significantly higher than that of the control group. Conclusion MIPO combined with Jintiange capsule can significantly improve the function recovery effect of shoulder joint, effectively stabilize bone mass index, promote the formation of bone structure, quickly recover bone metabolism function, and finally achieve fracture healing. It is worthy of clinical application.
基金supported by the National Key R&D Program of China(Grant No.2016YFC1102000)the National Natural Science Foundation of China(Grant Nos.81672139 and 81702129)+3 种基金the China Postdoctoral Science Foundation(No.171479)Doctor Initial Foundation of Liaoning Province(No.20170520017)Affiliated Zhongshan Hospital of Dalian University(No.DLDXZSYYDK201701)by a grant from the Research Grants Council of the Hong Kong Special Administrative Region,China(Project No.T13-402/17-N)。
文摘Bone plates play a vital role in bone fracture healing by providing the necessary mechanical fixation for fracture fragments through modulating biomechanical microenvironment adjacent to the fracture site.Good treatment effect has been achieved for fixation of bone fracture with conventional bone plates,which are made of stainless steel or titanium alloy.However,several limitations still exist with traditional bone plates including loosening and stress shielding due to significant difference in modulus between metal material and bone tissue that impairs optimal fracture healing.Additionally,due to demographic changes and non-physiological loading,the population suffering from refractory fractures,such as osteoporosis fractures and comminuted fractures,is increasing,which imposes a big challenge to traditional bone plates developed for normal bone fracture repair.Therefore,optimal fracture treatment with adequate fixation implants in terms of materials and design relevant to special conditions is desirable.In this review,the complex physiological process of bone healing is introduced,followed by reviewing the development of implant design and biomaterials for bone plates.Finally,we discuss recent development of hybrid bone plates that contains bioactive elements or factors for fracture healing enhancement as a promising direction.This includes biodegradable Mg-based alloy used for designing bone screw-plates that has been proven to be beneficial for fracture healing,an innovative development that attracts more and more attention.This paper also indicates that the tantalum bone plates with porous structure are also emerging as a new fracture internal fixation implants.The reduction of the stress shielding is verified to be useful to accelerate bone fracture healing.Potential application of biodegradable metals may also avoid a second operation for implant removal.Further developments in biometals and their design for orthopedic bone plates are expected to improve the treatment of bone fracture,especially the refractory fractures.
基金supported by the Dalian Science and Technology Innovation Fund Project(No.2018J11CY030).
文摘Metal plates have always been the gold standard in the clinic for internal fracture fixation due to their high strength advantages.However,high elastic modulus can cause stress shielding and lead to bone embrittlement.This study used an electron beam melting method to prepare personalized porous Ti6Al4V(pTi)bone plates.Then,chemical vapor deposition(CVD)technology coats tantalum(Ta)metal on the pTi bone plates.The prepared porous Ta-coated bone plate has an elastic modulus similar to cortical bone,and no stress shielding occurred.In vitro experiments showed that compared with pTi plates,Ta coating significantly enhances the attachment and proliferation of cells on the surface of the scaffold.To better evaluate the function of the Ta-coated bone plate,animal experiments were conducted using a coat tibia fracture model.Our results showed that the Ta-coated bone plate could effectively fix the fracture.Both imaging and histological analysis showed that the Ta-coated bone plate had prominent indirect binding of callus formation.Histological results showed that new bone grew at the interface and formed good osseointegration with the host bone.Therefore,this study provides an alternative to bio-functional Ta-coated bone plates with improved osseointegration and osteogenic functions for orthopaedic applications.
基金ThisstudywassupportedbythegrantsfromtheNationalNaturalScienceFoundationofChina (No .39470 6 98)
文摘To study the change of the stress shielding rate of stress-relaxation plate in vivo and its influence on fracture healing. Methods: The diaphyses of bilateral tibias in 70 New Zealand rabbits were osteotomized and fixed with stress-relaxation plates (SRP, the SRP group) and rigid plates (RP, the RP group), respectively. The fracture healing process in these 2 groups was investigated by radiography, light and polarized light microscopy and biomechanical test at 2 to 48 weeks postoperatively. Results: Early after fixation the stress shielding rate was about 70% in both groups. While in the SRP group the stress shielding rate decreased gradually as time passed, which was significantly lower than that of the RP group (P< 0.05 ) by the end of the 8th postoperative week, and stabilized at the level of about 27% at 36-48 weeks after fixation. Abundant external callus associated with the formation of cartilaginous callus could be observed in the SRP group at 2-4 weeks postoperatively. The transformation of the callus into the lamellar bone began at 8-12 weeks, the collagen gradually arranged in order, and the mechanical nature of the united bone was gradually strengthened, too. In the RP group, the external callus was scarce at the early stage of fracture healing, and the callus remodeling at the late stage of fracture healing was dominated by bone absorption. The ultimate bending strength (UBS) was only 57.95 % of that of the normal by 48 weeks. Conclusions: The decrease of the stress shielding rate of SRP in vivo was well interrelated with the time of fixation. The application of SRP could promote the callus formation and bone reconstruction thus to favor the recovery of the mechanical strength of the united bone.
文摘BACKGROUND The epiphyseal growth plate is an important anatomical segment localized on the ends of a long bone.Despite the abovementioned atractive reasons for alendronate’s use,few data on the effect of alendronate during epiphyseal growth exist.AIM Verify the effect of alendronate on the growth epiphyseal plate,and compare its effect with the size of the femur during the double-staining of the immunolocalization of transforming growth factor-β1(TGF-β1)and bone morphogenetic protein-2(BMP2)in endochondral ossifing in specimens that have received alendronate.METHODS Forty newborn rats were randomly divided into two groups:a control group(were given applications of 1 mg/kg physiologic saline)and a group that received Alendronate(a dose of 2.5 mg/kg).These groups were then divided into two subgroups for euthanasia in two and 12 d of life.After euthanasia,the femurs were removed,and the femoral bones were measured linearly between the apex of the greater trochanter until the lower intercondylar midlle face to verify the probable bone growth between 3 and 12 d in control and alednroanto treated rats.Posteriorly,the surgical pieces were also sent to the histopathology laboratory to produce histological slides.The obtained slides were stained with hematoxylin and eosin to measure each of the cartilage zones in endochondral development.and other slides were immunohistochemically tested for anti-TGF-β1 and BMP-2 antibodies to investigate the immunolocalization of these proteins in the epiphyseal plaque area.RESULTS On the third day,some diferences between the control group and specimens treated with alendronate were verified.Macroscopiccaly,we found similarities in size between the femoral bones when we compared the control group with the specimens that received alendronate.On the 12^th day,the bone size of the mice receiving the drug was significantly smaller than those of the control group.These results coincide with changes in the TGF-β1 and BMP-2 expression.In the specimens that received alendronate,the TGF-β1 was expressed in some sites of trabecular bone that was neoformed,peripherally to the bone marrow area.The BMP-2 was also positive in proliferative chondrocytes and hypertrofic chondrocytes.On the 12^th day,all layers of chondrocytes exhibited positivity for BMP-2 in the specimens that received alendronate.In the interface between the trabecular bone and cartilage,an area of disorganized bone deposition was evident.Neoformed bone also appeared to be different at 12 d.In the control group,BMP-2 was positive in an intense area of bone trabeculae,whereas the alendronate-treated group showed TGF-β1 positive trabeculae and a greater bone area.CONCLUSION Alendronate alters the immunolocalization of TGF-β1 and BMP-2 simultaneously,a condition that changes the usual histological aspects of the cartilage zone and impairs epiphysis growth and femur growth.
文摘The scanning electron microscope (SEM) results of bone interface of titanium-coated 317L plate screw are reported in this article. 317L plate screw had a rough surface composed of sprayed pure titanium which formed a bone/metal interface in biointegration after implanted into the mandible of dog. Though a bone/metal interface in osseointegration was also formed on the surface of uncoated 317L plate screw after implantation, a smal1 space was seen between the bone and surface of the screw, indicating that the tissue compatibility of titanium-coated 317L plate screw may be better than that of the non-coated screw.
文摘AIM: To determine whether use of a precontoured olecranon plate provides adequate fixation to withstand supraphysiologic force in a comminuted olecranon fracture model.METHODS: Five samples of fourth generation composite bones and five samples of fresh frozen human cadaveric left ulnae were utilized for this study. The cadaveric specimens underwent dual-energy X-ray absorptiometry(DEXA) scanning to quantify the bone quality. The composite and cadaveric bones were prepared by creating a comminuted olecranon fracture and fixed with a pre-contoured olecranon plate with locking screws. Construct stiffness and failure load were measured by subjecting specimens to cantilever bending moments until failure. Fracture site motion was measured with differential variable resistance transducer spanning the fracture. Statistical analysis was performed with two-tailed Mann-Whitney-U test with Monte Carlo Exact test.RESULTS: There was a significant difference in fixation stiffness and strength between the composite bones and human cadaver bones. Failure modes differed in cadaveric and composite specimens. The load to failure for the composite bones(n = 5) and human cadaver bones(n = 5) specimens were 10.67 nm(range 9.40-11.91 nm) and 13.05 nm(range 12.59-15.38 nm) respectively. This difference was statistically significant(P ? 0.007, 97% power). Median stiffness for composite bones and human cadaver bones specimens were 5.69 nm/mm(range 4.69-6.80 nm/mm) and 7.55 nm/mm(range 6.31-7.72 nm/mm). There was a significant difference for stiffness(P ? 0.033, 79% power) between composite bones and cadaveric bones. No correlation was found between the DEXA results and stiffness. All cadaveric specimens withstood the physiologic load anticipated postoperatively. Catastrophic failure occurred in all composite specimens. All failures resulted from composite bone failure at the distal screw site and not hardware failure. There were no catastrophic fracture failures in the cadaveric specimens. Failure of 4/5 cadaveric specimens was defined when a fracture gap of 2 mm was observed, but 1/5 cadaveric specimens failed due to a failure of the triceps mechanism. All failures occurred at forces greater than that expected in postoperative period prior to healing.CONCLUSION: The pre-contoured olecranon plate provides adequate fixation to withstand physiologic force in a composite bone and cadaveric comminuted olecranon fracture model.
文摘The locking compression plates (LCP) are efficient tools in open reduction and internal fixation (ORIF), especially in osteoporotic bones. Two important factors of screw density and screw position can affect the functionality of the bone plate. Several studies have assessed the influence of the screw configurations on the bone-plate stiffness, but the effects of screw positions on the interfragmentary strain, εIF of LCP construct have not been investigated yet. In this study, finite element method was used to investigate the influence of screws number and position on the interfragmentary strain of LCP-femur system for a mid-shaft fracture. Results of this study showed that by insertion of screws closer to the fracture site, εIF decreases by 2nd degree polynomial function versus screw position, but by adding the screws from the ends of the plate, or by moving and placing the screws towards the fracture site, the reduction of εIF will be linear. Results of this study were compared and are in agreement with some studies in the literature, even though their scope was mostly stability of the bone-implant system, whereas our scope was focused on the interfragmentary strain.
文摘Acetabular component revision in the presence of severe bone loss is difficult for reconstructing an acetabular component in the anatomical hip center. Various treatment options are available, although often the acetabular defect cannot be corrected with a single option alone. Precise assessment of the bone loss and a suitable combination of methods are needed. Here we report a case of multiple failures with impaction bone grafting reconstruction for an acetabular bone defect of American Academy of Orthopedic Surgeons classification type III. We finally reconstructed the acetabulum with three femoral head allografts and a Kerboull-type acetabular reinforcement device. The allograft was a casted, jet-type helmet-like shape. A year later the patient was able to walk without a cane and perform light agricultural work. Accurate evaluation of the acetabular bone loss and appropriate reconstruction is important.
