Fresh autogeneic, frozen allogeneic, and decalcified allogeneic bone grafts in dogs

In fully-grown mongrel dogs, diaphyseal ulnar defects 25 mm long were stabilised by screws and plates, and were temporarily filled with silicone rubber blocks. After eight weeks the block was replaced either by fresh autogeneic cancellous bone, allogeneic deep-frozen cancellous bone, allogeneic decalcified bone matrix, or bone matrix gelatin. After 24 weeks the implants were evaluated by radiography, histology, and measurements of new bone volume, using computer-assisted density registration on microradiographs. Only the autogeneic bone grafts led to healing in all instances. Bone regeneration in the other groups was not significantly better than in the sham group in which no graft was employed. Decalcified bone matrix proved ineffective.     

Critically sized osteo-periosteal femoral defects: a dog model.

A 21-mm defect was created in 1 femoral diaphysis each of 15 dogs. Periosteum as well as a cylinder of bone was removed, and the defect was stabilized with a bone plate. Twelve of the defects were filled with an equal volume of autogenous cancellous bone harvested from the ipsilateral ilium. Three defects were left untreated. Cranial to caudal radiographs were taken postoperatively and every 4 weeks for 16 weeks. The radiographs were evaluated for healing using two ordinal scales. At 16 weeks, the dogs were euthanized and the femurs harvested for biomechanical testing and histologic evaluation. Both operated and contralateral not operated femurs were mechanically tested to failure in torsion, and load at failure and stiffness were calculated. All dogs tolerated the procedure well, and were using the operated limb within 1 or 2 days postoperatively. There were no complications noted during the 16 weeks of the study. Unfilled defects did not heal and became atrophic nonunions. The defects filled with autogenous cancellous bone healed in a consistent pattern of consolidation, incorporation, and remodeling, with uniform increases of both ordinal scales used. The femoral cortex opposite the bone plate demonstrated most mature remodeling, evident both radiographically as well as histologically. Unoperated femurs failed at 13.61 +/- 3.88 N-m and grafted femurs failed at 2.96 +/- 1.3 N-m, which was 23% of the measurement of the unoperated femur. Relative stiffness of the unoperated femurs was 5974 +/- 4316 N-m2/radian, and grafted femurs had a relative stiffness of 642 +/- 561 N-m2/radian, which was 10.4% of the measurement of unoperated femur. This model proved to be a critically sized defect, which when left unfilled resulted in an atrophic nonunion, and when filled with cancellous bone resulted in a consistent healing pattern.     

Critically Sized Osteo-Periosteal Femoral Defects: A Dog Model

A 21-mm defect was created in 1 femoral diaphysis each of 15 dogs. Periosteum as well as a cylinder of bone was removed, and the defect was stabilized with a bone plate. Twelve of the defects were filled with an equal volume of autogenous cancellous bone harvested from the ipsilateral ilium. Three defects were left untreated. Cranial to caudal radiographs were taken postoperatively and every 4 weeks for 16 weeks. The radiographs were evaluated for healing using two ordinal scales. At 16 weeks, the dogs were euthanized and the femurs harvested for biomechanical testing and histologic evaluation. Both operated and contralateral not operated femurs were mechanically tested to failure in torsion, and load at failure and stiffness were calculated. All dogs tolerated the procedure well, and were using the operated limb within 1 or 2 days postoperatively. There were no complications noted during the 16 weeks of the study. Unfilled defects did not heal and became atrophic nonunions. The defects filled with autogenous cancellous bone healed in a consistent pattern of consolidation, incorporation, and remodeling, with uniform increases of both ordinal scales used. The femoral cortex opposite the bone plate demonstrated most mature remodeling, evident both radiographically as well as histologically. Unoperated femurs failed at 13.61 3.88 N-m and grafted femurs failed at 2.96 1.3 N-m, which was 23% of the measurement of the unoperated femur. Relative stiffness of the unoperated femurs was 5974 4316 N-m2/radian, and grafted femurs had a relative stiffness of 642 561 N-m2/radian, which was 10.4% of the measurement of unoperated femur. This model proved to be a critically sized defect, which when left unfilled resulted in an atrophic nonunion, and when filled with cancellous bone resulted in a consistent healing pattern.     

The use of demineralized bone matrix in the repair of segmental defects. Augmentation with extracted matrix proteins and a comparison with autologous grafts

A soluble protein component of bone, bone morphogenetic protein, and decalcified bone matrix have been shown to induce the formation of bone in extraosseous tissue. Clinical and animal studies investigating the use of these materials as bone grafts have shown radiographic and histological evidence of formation of bone, but the clinical usefulness of these grafts remains unknown. This study compared the healing processes when plasma-coated demineralized bone matrix and autologous cancellous bone were used to graft segmental defects of bone. A standard procedure was used to make a two-centimeter defect bilaterally in the ulna of forty-eight skeletally mature New Zealand White rabbits. In each rabbit, one ulnar defect was grafted with autologous citrated plasma-coated demineralized bone matrix while the other defect served as a control and was grafted with either autologous cancellous bone from the iliac crest, demineralized bone matrix, or demineralized bone matrix augmented with bone proteins that had been extracted with guanidinium hydrochloride. The ulnar defect was stabilized by the intact radius, and no supplemental device was necessary for fixation. To examine spontaneous healing in this model, one group of rabbits had a control defect that was not grafted. The grafts were periodically evaluated by radiographs, and twelve weeks after surgery the grafts were harvested and tested to failure in a standard torsion-test machine. The mechanical parameters were calculated, and histological examination of major fragments of the grafts was performed. The results of the radiographic and histological evaluation showed that all of the grafted ulnae healed, with fusion of the graft to the cut ends of the defect and reformation of approximately normal anatomy. No ungrafted ulnar defects healed. The results from the mechanical tests were evaluated by comparing the defect that was grafted with plasma-coated demineralized bone matrix with the control graft in each animal. These data showed that: twelve weeks after grafting, the normal ulnae were significantly stronger than the ulnae that had been grafted with plasma-coated demineralized bone matrix; the ulnae that had been grafted with plasma-coated demineralized bone matrix and those that had been grafted with autologous bone were equivalent in strength; and twelve weeks after grafting, grafts of demineralized bone matrix that were augmented with extracted bone proteins were significantly stronger than those that had not been so augmented.     

The efficacy of cylindrical titanium mesh cage for the reconstruction of a critical-size canine segmental femoral diaphyseal defect.

The authors developed a novel technique for the reconstruction of large segmental long bone defects using a cylindrical titanium mesh cage (CTMC). Although the initial clinical reports have been favorable, the CTMC technique has yet to be validated in a clinically relevant large animal model, which is the purpose of this study. Under general anesthesia, a unilateral, 3-cm mid-diaphyseal segmental defect was created in the femur of an adult canine. The defect reconstruction technique consisted of a CTMC that was packed and surrounded with a standard volume of morselized canine cancellous allograft and canine demineralized bone matrix. The limb was stabilized with a reamed titanium intramedullary nail. Animals were distributed into four experimental groups: in Groups A, B, and C (six dogs each), defects were CTMC reconstructed, and the animals euthanized at 6, 12, and 18 weeks, respectively; in Group D (three dogs), the same defect reconstruction was performed but without a CTMC, and the animals were euthanized at 18 weeks. The femurs were harvested and analyzed by gross inspection, plain radiography, computed tomography (CT), and single photon emission computed tomography (SPECT). The femurs were mechanically tested in axial torsion to failure; two randomly selected defect femurs from each group were analyzed histologically. Groups A, B, and C specimens gross inspection, plain radiography, and CT, demonstrated bony restoration of the defect, and SPECT confirmed sustained biological activity throughout the CTMC. Compared to the contralateral femur, the 6-, 12-, and 18-week mean defect torsional stiffness was 44.4, 45.7, and 72.5%, respectively; the mean torsional strength was 51.0, 73.6, and 83.4%, respectively. Histology documented new bone formation spanning the defect. Conversely, Group D specimens (without CTMC) demonstrated no meaningful bone formation, biologic activity, or mechanical integrity at 18 weeks. The CTMC technique facilitated healing of a canine femur segmental defect model, while the same technique without a cage did not. The CTMC technique may be a viable alternative for the treatment of segmental long bone defects.     

An evaluation of human demineralized bone matrices in a rat femoral defect model

The osteoconductive and osteoinductive potential of two human allogeneic demineralized bone matrix putties were compared in a critical-sized athymic rat femoral defect model. Defects were treated with (1) a demineralized bone matrix in a hyaluronic acid carrier, (2) a demineralized bone matrix in a glycerol carrier, (3) a hyaluronic acid carrier alone, or (4) with no implant. Radiographic examinations and histologic analyses were done at 4, 8, and 16 weeks postoperatively. Eight of the 48 defects treated with a demineralized bone matrix and none of the 36 surgical controls showed complete radiographic healing by 16 weeks and no statistically significant difference between the radiographic scores for the two demineralized bone matrix preparations was found. On histologic review, both preparations of demineralized bone matrix had passive remineralization. The largest foci of endochondral ossification were seen in limbs treated with a demineralized bone matrix in a hyaluronic acid carrier. The 8-mm rat femoral defect allows for stringent assessment of the osteoinductive potential of bone graft substitutes. Hyaluronic acid and glycerol are viable carriers for demineralized bone matrices. As both de-mineralized bone matrices tested provided an adequate osteoconductive matrix and showed some, although limited, osteoinductive capacity, these materials should be used in clinical practice only as bone graft extenders or enhancers.     

The bone inductive capacity of various bone transplanting materials used for treatment of experimental bone defects.

The bone defect repairing capacities of autogenous cancellous bone (ACB), decalcified bone (DB), autodigested "low-antigenic" bone matrix (LBM) and preserved bone (PB) were tested in experimental defects in rabbit scapulae. The healing of the defects was most effective with ACB transplants as judged by roentgenologic and microscopic studies. The DB and LBM transplants caused states of healing comparable to each other, and the PB transplants showed the least satisfactory results in this experiment. The ACB, DB and LBM transplants caused bone induction, which resulted in the formation of new bone, subsequent resorption of the transplanted material and rapid reshaping of the callus. The PB transplants caused no bone induction; only some growth of callus on the edges of the defect was observed and pieces of the transplanted material were seen as late as 10 weeks after the operation as dead particles encapsulated by fibrous tissue. The infiltrations of inflammatory cells around the PB transplants indicated a considerable host versus graft reaction whereas this reaction was less with the other materials tested.     

新型硫酸钙和脱钙骨基质混合物的临床应用

目的 评价新型硫酸钙和脱钙骨基质混合物作为骨移植替代物的临床应用效果. 方法 2005年2月至2008年2月采用新型人工骨移植治疗51例患者,按照植入物不同分为两组:人工骨与自体骨混合组21例,即植人硫酸钙和脱钙骨基质混合物加自体骨;单纯人工骨组30例,只植入硫酸钙和脱钙骨基质混合物.术后定期复查,观察人工骨吸收和新骨生长情况. 结果 51例切口一期愈合,无局部红肿、渗出.3例患者失访,48例随访6～36个月,平均16个月.单纯人工骨组术后4周可见人工骨部分吸收,颗粒形态模糊,术后8～12周(平均9.6周)完伞吸收,可见新生骨质,术后8～16周(平均11周)骨性愈合.人工骨与自体骨混和组术后8～12周(平均11.5周)人工骨颗粒完全吸收,骨折不愈合患者术后14～24周(平均19周)获骨性愈合,其余患者术后9～20周(平均13周)获骨性愈合. 结论 新型人工骨能够发挥增加移植物容量、促进骨生成的作用,无局部不良反应,是一种安全有效的骨移植替代物.     

Bone grafting of cryosurgically treated bone defects: experiments in goats

It is hypothesized that cryosurgically treated bone defects are inappropriate host sites for cancellous bone grafting. The influence of autologous cancellous bone grafting on the healing of cryosurgically treated gap defects of long bones was investigated. A unilateral in vivo experiment was done to study bone strength and graft incorporation in the goat. The lining of a cylindrical defect of the femoral diaphysis was treated with a closed liquid nitrogen cryoprobe in 62 goats. Thirty-one animals received an impacted, morselized, cancellous bone graft harvested from the sternum. The other 31 animals served as controls. At 0, 4, 7, 10, 13, 16, and 26 weeks animals were euthanized and the femurs were evaluated for torsional strength, computed tomography, and histologic assessment. Specimens with a bone graft showed no significant increase in torsional strength with time compared to the controls. In all goats euthanized at 10 weeks or later, the graft was resorbed. The amount of bone apposition at the site of the cryosurgical lesion and the time at which the defect was bridged were similar in both groups. Autologous cancellous bone grafting does not accelerate healing of cryosurgically treated, stable, diaphyseal defects in the goat.     

Treatment of nonunion by percutaneous injection of bone marrow and demineralized bone matrix. An experimental study in dogs

Successful treatment of nonunited fractures remains a major clinical challenge. Because bone marrow and demineralized bone matrix (DBM) are capable of stimulating osteogenesis, experiments were designed to test the effectiveness of bone marrow or DBM or both when injected percutaneously into a canine nonunion model. Six-millimeter segmental defects were created in the midtibial diaphysis of 24 adult mongrel dogs and held distracted by external fixation. For comparative purposes, a 0.5-mm osteotomy was created in five dogs. Five weeks later, the 6-mm defects were injected with either saline, autogeneic marrow, DBM powder, a composite of bone marrow and DBM, or treated by open grafting techniques with autogenic cancellous bone. Healing of the defect was evaluated roentgenographically, biomechanically (three-point bending), histologically, and biochemically 13 weeks postsurgery. Marrow and DBM stimulated defect healing. However, the combination of bone marrow with DBM produced a synergistic response in the defect, which was greater than the sum of either marrow or DBM alone. Healing in the composite-grafted dogs was comparable to those treated by standard cancellous bone grafting. These data suggest that percutaneous injection of bone marrow and DBM may be a potential alternative that offers numerous advantages over standard open grafting techniques in the treatment of fractures with nonunited defects.     

异体软骨痂移植的初步结果

目的 通过观察异体软骨痂移植后的生物学过程判断其作为植骨材料的可行性。方法 将1只SD大鼠的双侧股骨干造成闭合骨折,1周时切开获取软骨痂,－196℃冻存2周后移植于5只SD大鼠的左侧胫骨干部分缺损区（此骨缺损模型的成骨活动只表现为膜内化骨的方式）,右侧植入异体松质骨作为对照组。将取材标本制成不脱钙切片,经亮绿和藏红T染色。结果 术后1周取材1例,缺损区实验侧和对照侧均未见有软骨组织和骨组织形成。术后2周处死其余4只大鼠,实验侧（3／4）可见有软骨组织和骨组织形成。骨组织内已有髓腔形成,骨组织周围是软骨组织,与宿主骨之间有纤维组织相隔。结论 异体软骨痂移植后未被吸收,可经软骨内化骨的方式产生骨组织,为软骨痂作为植骨材料的进一步研究和开发提供了初步依据。     

三种生物骨衍生材料修复节段性骨缺损的实验研究

目的　评价 3种生物骨衍生材料修复节段性骨缺损的成骨作用。　方法　将 6 0只健康日本大耳白兔双侧桡骨中段制成 10 mm节段性骨缺损 ,并随机分为 A、B、C、D和 E组 ,每组 12只 ,其中 A组植入复合型完全脱蛋白骨 (composite fully deproteinised bone,CFDB)、B组植入部分脱蛋白骨 (partially deproteinised bone,PDPB)、C组植入部分脱钙骨 (partially decalcified bone,PDCB)修复兔桡骨节段性缺损 ,D组自体髂骨移植 ,E组以空白缺损为对照 ,于术后4、8、12及 2 4周取材 ,通过 X线摄片和不脱钙硬组织切片检测 ,评价 3种材料的成骨作用。　结果　 X线摄片观察 :A、B与 C组 4周时材料密度较高 ;8周时材料与宿主骨交界处模糊 ;12周时材料边缘部分区域密度接近宿主骨 ;2 4周时 B组髓腔再通 ,C组缺损区域密度大部分接近宿主骨 ,有少许高密度影 ,A组缺损区域有较多高密度影。 X线片评分 4周和8周时各材料组无统计学差异 (P>0 .0 5 ) ;12周时 B组和 C组高于 A组 (P<0 .0 5 ) ;2 4周时 D组 >B组 >C组 >A组(P<0 .0 5 )。经组织学形态观察可见 4周和 8周时新骨贴附材料生长 ;以后新骨增多 ;材料随着时间的推移逐渐降解吸收 ;2 4周时成骨量 D组 >B组 >C组 >A组 (P<0 .0 5 )。　结论　 PDPB修复节段性骨缺损的效果佳 ,     

Demineralized bone matrix and hydroxyapatite/tri-calcium phosphate mixture for bone healing in rats

Purpose: Hydroxyapatite/tri-calcium phosphate (HA/TCP) mixture is an osteoconductive material used as a bone graft substitute, and demineralised bone matrix (DBM) is an osteoinductive material. A combination of DBM and HA/TCP mixture would probably create a composite with both osteoconductive and osteoinductive properties. The purpose of this study was to determine the effect of the combination of DBM and HA/TCP mixture on healing of rat radius segmental defects. Methods: Twenty-four adult male Wistar rats were used. Bilateral radial defects were created in each animal. Radial defects were implanted with DBM, HA/TCP mixture and a combination of both substances. Control defects were left unfilled. Ten weeks after implantation, the animals were sacrificed, and the radii were evaluated by radiograhic and histopathological studies. Results: The use of DBM alone demonstrated improved healing on radiographic and histological studies compared to other groups and the control group. There were no differences between the other two groups and the control group. Conclusion: The DBM group showed the best healing response. Combined use of DBM and HA/TCP mixture did not improve bone healing, and the osteoinductive properties of DBM were inhibited by HA/TCP mixture.     

A radiographical and biomechanical study of demineralized bone matrix implanted into a bone defect of rat femurs with and without bone marrow

Repair of large bone defects represents a challenge to orthopedic surgery since autogenous graft is not available in large amounts. Demineralized bone matrix (DBM) which contains bone morphogenic protein, a potent osteoinductive glycoprotein, and collagen, an osteoconductive matrix, may be an effective substitute for these graft materials. Bone marrow which contains osteoprogenitor cells could potentiate the osteoinductive and osteoconductive properties of demineralized bone matrix. This study tested the ability of demineralized bone matrix with and without bone marrow to bridge large segmental defects, and evaluated the results both radiographically and biomechanically as compared to autogenous (isogeneic) cancellous bone graft. Demineralized bone-matrix segments implanted into a plated femoral segmental defect in rats resulted in firm union in most animals. Bone marrow significantly enhanced bone formation of demineralized bone-matrix implants at an early stage but with time, differences between bone marrow-augmented and bone marrow-deprived demineralized bone implants were no longer demonstrable radiographically and biomechanically. Newly formed bone had about 50% of the strength of the contralateral control bones. Femurs implanted with cancellous bone isografts had similar evidence of absolute union rate, radiographic and mechanical properties as DBM-implanted femurs.     

Combined use of platelet-rich plasma and autologous bone grafts in the treatment of long bone defects in mini-pigs

The use of platelet-rich plasma (PRP) for improving of bone defect healing is discussed controversially. The aim of this study was to assess the effect of PRP in combination with autologous cancellous graft on bone defect healing in a critical metaphyseal long bone defect. A critical size defect in the tibial metaphysis of 16 mini-pigs was filled either with autologous cancellous graft as control group or with autologous cancellous graft combined with autologous PRP. Compared to native blood platelets were enriched about 4.9-fold in the PRP. After 6 weeks, the specimens were assessed by X-ray and histological evaluation. Histomorphometrical analysis revealed that the area of new bone was significantly higher in the PRP group concerning the central area of the defect zone (p < 0.02) as well as the cortical defect zone (p < 0.01). All defects showed substantial new bone formation, but only defects of the PRP group regenerated entirely. The PRP group was superior to the control group even in the semi-quantitative assessment of the osseous bridging in both observed areas of the defect. Within the limits of the present study it could be demonstrated that PRP combined with autologous cancellous graft leads to a significantly better bone regeneration compared to isolated application of autologous cancellous graft in an in vivo critical size defect on load-bearing long bones of mini-pigs.     

The effect of demineralized bone matrix-calcium sulfate with vancomycin on calcaneal fracture healing and infection rates: a prospective study

BACKGROUND: Displaced intra-articular calcaneal fractures may have a central cancellous bone defect area. We hypothesized that human demineralized bone matrix (DBM) calcium sulfate (CaSO(4)) might act as a reasonable alternative to autograft in calcaneal fractures. When combined with antibiotic powder, this bone graft substitute also may act as a local antibiotic delivery device. This is the first clinical study evaluating bone healing and complications associated with DBM-calcium sulfate bone graft substitute in the treatment of displaced intra-articular calcaneal fractures with a central cancellous bone defect. METHODS: Over a 29-month period, 33 displaced intra-articular calcaneal fractures with central cancellous defects were treated with open reduction and internal fixation (ORIF) and grafting with vancomycin/DBM-calcium sulfate bone graft substitute. Eleven fractures without bone defects were treated with ORIF only. Patient demographics, medical history, and CT fracture classification were recorded. Postoperatively, fractures were monitored every 2 weeks for healing and complications. RESULTS: The mean time to union was 8.2 weeks in the grafted, while the control group mean time to union was 10.4 weeks (p = 0.0117). Wound problems occurred in five (15%) of the 33 patients with grafting, all in type III fractures with severe soft-tissue swelling, and included two minor wound healing delays, and three serious wound problems. At a mean followup time of 22.4 months, no DBM-calcium sulfate grafted calcaneus demonstrated evidence of osteomyelitis. CONCLUSIONS: This is the first study examining human DBM-calcium sulfate bone graft substitute to treat displaced intra-articular calcaneal fractures. Based on these initial data, human DBM-calcium sulfate acted as an acceptable and safe autograft alternative in displaced intra-articular calcaneal fractures with moderate (5 cc to 10 cc) central cancellous bone defects.     

骨髓基质成骨细胞-松质骨基质复合人工骨修复颅骨缺损的实验研究

目的 观察松质骨基质－骨髓基质成骨细胞复合工人骨在骨缺损区的成骨作用，探索该组织工程化人工骨修复颅骨缺损的可行性。方法 成年新西兰兔骨髓细胞体外培养、诱导后，接种于藻酸盐－松质骨基质中，形成松质骨基质－藻酸盐－骨髓基质成骨细胞复合人工骨，修复自体颅骨缺损。分别植入松质骨基质和骨髓基质成骨细胞作为对照。植入4周和8周后行X线摄片和组织学检查，观察骨形成情况。结果 复合人工成骨量优于单纯植入松质骨基持或骨髓基质成骨细胞组，并明显优于空白对照。结论 松质骨基质－骨髓基质成骨细胞复合人工骨髓修复颅骨缺损效果良好，可以作为临床大型骨缺损修复的途径之一。     

Effect of pulsed electromagnetic fields (PEMF) on late-phase osteotomy gap healing in a canine tibial model.

The effects of a pulsed electromagnetic field (PEMF) on late bone healing phases using an osteotomy gap model in the canine mid-tibia were investigated. A transverse mid-diaphyseal tibial osteotomy with a 2-mm gap was performed unilaterally in 12 adult mixed-breed dogs and stabilized with external fixation. Animals in the variable group (n = 6) were treated with PEMF for 1 h daily starting 4 weeks after surgery for a total of 8 weeks, whereas no stimulation signal was generated in the control group (n = 6). Functional load-bearing and radiographic assessments were conducted time-sequentially until euthanasia 12 weeks after surgery. Torsional tests and an analysis of undecalcified histology were performed on the retrieved mid-tibial diaphysis containing the osteotomy site. In the PEMF group, load-bearing of the operated limb recovered earlier when compared to the control group (p < 0.05). Load-bearing in the PEMF group at 8 weeks was greater than in the control group (p < 0.02). The periosteal callus area increased following surgery at 6 weeks (p < 0.05) and thereafter (p < 0.01) in the PEMF group, while a significant increase was observed at 8 and 10 weeks after surgery (p < 0.05) in the control group. Both the normalized maximum torque and torsional stiffness of the PEMF group were significantly greater than those of the control group (p < 0.04 and p < 0.007, respectively). Histomorphometric analyses revealed greater new-bone formation (p < 0.05) in the osteotomy gap tissue and increased mineral apposition rate (p < 0.04) and decreased porosity in the cortex adjacent to the osteotomy line (p < 0.02) in the PEMF group. PEMF stimulation of 1 h per day for 8 weeks provided faster recovery of load-bearing, a significant increase in new bone formation, and a higher mechanical strength of the healing mid-tibial osteotomy. This study revealed enhancing effects of PEMF on callus formation and maturation in the late-phase of bone healing.     

Effect of alendronate on fracture healing and bone remodeling in dogs

To examine the effect of alendronate (4-amino-1-hydroxybutylidene bisphosphonate) on fracture repair, the drug was given to mature beagle dogs orogastrically at 2 mg/kg/day for 9 weeks preceding fracture, 16 weeks after fracture, or both before and after fracture (25 weeks). A transverse mid-diaphyseal fracture of the right radius was surgically induced and was stabilized by external coaptation splinting. Fracture healing and bone remodeling were evaluated by radiography, gross and histological examination, and bone histomorphometry. The mechanical properties of the fracture callus were determined by a four-point bending test. Radiographs and gross and microscopic examination demonstrated normal bone healing at the fracture site in all dogs. In dogs that received alendronate during the fracture healing period, at 16 weeks the calluses were approximately 2–3 times larger than those in dogs that received a placebo during the healing period. This is consistent with slower callus bone remodeling, an expected pharmacological effect of the compound. Bone histomorphometry demonstrated that treatment with alendronate did not inhibit bone formation or mineralization. Mechanical testing showed that the ultimate load at failure and the flexural rigidity of both the fractured and contralateral intact bone were unaffected by treatment with alendronate. Therefore, in this study, treatment with alendronate before or during fracture healing, or both, resulted in no adverse effects on the union, strength, or mineralization of bone in mature beagle dogs.     

管型与非管型脱钙骨基质支架材料成骨活性差别的实验研究

目的探讨管型与非管型骨缺损修复材料成骨活性的差别。方法以兔同种异体尺桡骨脱钙骨基质为原料,制成管型(A组)及非管型(B组)修复材料各30只,随机植入30只兔双侧桡骨中上段1.5 cm骨缺损中,分别于术后1、2、4、8、12周随机处死6只取材进行X线、组织学切片、大体观察、单位湿重Ca值等检查,结果进行统计学处理。结果早期(术后2周)A组具有更多的骨痂生成(P<0.05)、更高的单位湿重Ca值(P<0.05);中期(术后4周)A组编织骨具有更高的孔隙率(P<0.05);后期(术后8、12周)A组表现为更薄的板层骨、更好的髓腔再通率、更好的塑形、更成熟的骨髓形成(P<0.05)、更高的单位湿重Ca值(P<0.05)。结论实验显示管型脱钙骨基质较非管型具有更好的节段性骨缺损修复能力,提示管型人工骨治疗节段性骨缺损具有美好的前景。