同种异体皮质骨板移植免疫学研究

目的: 探讨实验动物和患者接受不同方法处理的同种异体皮质骨板移植后宿主免疫学反应。方法: 48只山羊接受分别经过 -70℃深低温冷冻 4周、 -70℃深低温冷冻 4周 48℃环氧乙烷灭菌、-70℃深低温冷冻 4周 25kGyγ射线辐照处理的同种异体皮质骨板移植,对照组移植异体山羊新鲜皮质骨板。7例髋关节置换术后股骨假体周围骨折患者, 接受深低温冷冻和环氧乙烷处理同种异体皮质骨板移植重建股骨骨折。检测实验动物外周血CD4 、CD8 以及患者外周血T淋巴细胞亚群、抗体、补体和循环免疫复合物。结果: 新鲜骨板移植组CD4 明显升高, 术后 6周达到顶峰。除深低温组术后 6周CD4 升高外, 深低温冷冻、深低温冷冻 环氧乙烷及深低温冷冻 γ射线辐照组T淋巴细胞亚群无明显改变。患者T淋巴细胞亚群、抗体和免疫复合物正常, 切口无感染。结论: 新鲜同种异体皮质骨板具有抗原性, 移植后诱发宿主免疫排斥反应; 深低温冷冻、深冻 环氧乙烷和深冻 γ射线辐照处理同种异体皮质骨板移植受体无明显免疫排斥反应。     

Fracture resistance of gamma radiation sterilized cortical bone allografts.

Gamma radiation is widely used for sterilization of human cortical bone allografts. Previous studies have reported that cortical bone becomes brittle due to gamma radiation sterilization. This embrittlement raises concern about the performance of a radiation sterilized allograft in the presence of a stress concentration that might be surgically introduced or biologically induced. The purpose of this study was to investigate the effect of gamma radiation sterilization on the fracture resistance of human femoral cortical bone in the presence of a stress concentration. Fracture toughness tests of specimens sterilized at a dose of 27.5 kGy and control specimens were conducted transverse and longitudinal to the osteonal orientation of the bone tissue. The formation of damage was monitored with acoustic emission (AE) during testing and was histologically observed following testing. There was a significant decrease in fracture toughness due to irradiation in both crack growth directions. The work-to-fracture was also significantly reduced. It was observed that the ability of bone tissue to undergo damage in the form of microcracks and diffuse damage was significantly impaired due to radiation sterilization as evidenced by decreased AE activity and histological observations. The results of this study suggest that, for cortical bone irradiated at 27.5 kGy, it is easier to initiate and propagate a macrocrack from a stress concentration due to the inhibition of damage formation at and near the crack tip.     

同种异体皮质骨板移植治疗股骨假体周围骨折

目的 评价同种异体皮质骨板移植治疗髋关节股骨假体周围骨折的临床治疗效果。方法 对7例髋关节置换术后股骨假体周围骨折患者应用深低温冷冻和环氧乙烷处理同种异体皮质骨板移植治疗股骨骨折。根据Harris评分,外周血T淋巴细胞亚群、抗体和免疫复合物检测、X线摄片以及核素骨显像评价其治疗效果。结果 患者未发生免疫排斥反应和感染,术后3、6、12、24个月Harris评分分别比术前平均增加21、32、40、40分。术后3个月骨折愈合,一部分移植骨板与宿主骨骨性连接,同位素骨显像骨板移植区放射性分布比对侧浓集。术后12个月,85％移植骨板与宿主骨融为一体,宿主股骨皮质厚度增加3～5mm,平均4．3mm,骨板放射性浓集进一步加深,15％移植骨板出现吸收现象。术后24个月,80％移植骨板重新塑形后恢复宿主股骨皮质骨密度,10％骨板表面吸收停止,股骨假体无松动。结论 深低温冷冻和环氧乙烷处理同种异体皮质骨板移植无菌、抗原性弱、生物相容性好,移植骨板能够维持骨折和假体稳定性,增加股骨局部骨量储备,避免再次手术取出金属内置物,是用来治疗股骨假体周围骨折较理想的方法之一。     

The mechanical and biological properties of demineralised cortical bone allografts in animals

We studied the calcium content and mechanical strength of cortical bone from rats and dogs after different periods of demineralisation, showing that the rate of demineralisation differed considerably between the species. Specimens from the rat were further treated by chemical extraction and autolysis and tested for osteoinductive properties. We showed that partially demineralised cortical bone retained adequate mechanical strength, while retaining the biological effects of completely demineralised bone. This shows that it is possible to prepare allografts which have adequate mechanical strength and still retain osteo-inductive properties.     

Histologic evidence of cortical allograft bone incorporation in revision hip surgery

There is no published evidence concerning the histology of cortical allograft bone implanted during revision arthroplasty surgery. Five cases are reported in which cortical allograft bone had been used where biopsies were available between 2 and 27 months after implantation. All cases showed favorable histologic features, with soft tissue attachment by fibrous adhesion, union of graft to host, and osseous remodeling.     

Role of growth factors in the incorporation of unloaded bone allografts in the goat

Revision of a failed total joint replacement often demands bone grafting methods to restore deficient bone stock. However, impaired allograft incorporation can be the result of inadequate host or graft properties. The stimulation of bone healing with growth factors could provide a new approach to deal with this problem. The repeated sampling bone chamber was used in the goat to investigate the properties of bone allografts enriched with transforming growth factor-beta, recombinant human bone morphogenetic protein-2, and basic fibroblastic growth factor under unfavorable vascular and nonloaded conditions. Ten goats each had three bone chambers implanted in the medial proximal tibia. Different carrier allograft bone preparations were used for each growth factor based on convention and previously reported results. The period between implantation and chamber harvest was 8 weeks. The concentrations of the growth factors used was 0, 1, or 10 micrograms of transforming growth factor-beta 2, 0, 1, or 5 micrograms of bone morphogenetic protein-2, and 0, 40, 200 ng of basic fibroblastic growth factor. The specimens were analyzed histomorphometrically for the amount of soft tissue ingrowth, bone ingrowth, and the number of osteoclasts. In all specimens, a resorption front grew into the graft followed by fibrovascular tissue and, in some instances, bone. In the 5 micrograms of bone morphogenetic protein-2 specimens, larger amounts of soft tissue and woven bone were present, whereas in the specimens that received 10 micrograms of transforming growth factor-beta 2, there was a decrease in the amount of tissue and bone ingrowth. Two hundred nanograms of basic fibroblastic growth factor had a negative effect on soft tissue formation but increased the amount of vascular elements containing erythrocytes. The number of osteoclasts was higher in the 5-microgram bone recombinant human morphogenetic protein-2 specimens. In the clinical arena with absence of good perigraft vascularization and loading, bone morphogenetic protein-2 may have a strong stimulatory effect on bone graft incorporation.     

Incorporation of vancomycin-supplemented bone incorporation of vancomycin-supplemented bone allografts: radiographical, histopathological and immunohistochemical study in pigs

We compared the incorporation of bone allografts with or without vancomycin in tibial defects of 18 pigs. High-quality radiographs, histological examination, immunological expression of metalloproteinase-13 (MMP-13) and transforming growth factor-beta 2 (TGFbeta2) indicated that there was no significant difference in bone allograft incorporation between up to 220 times the MIC (minimum inhibitory concentration) in bone allografts with 1 g of vancomycin in each 300 g of allograft or without this supplement.     

异体皮质骨板在股骨髁部粉碎性骨折内固定术中的应用

目的探讨异体皮质骨板股骨内侧辅助固定结合外侧解剖型钢板内固定治疗股骨髁部粉碎性骨折的临床疗效。方法自2006-03—2013-06采用异体皮质骨板股骨内侧辅助固定结合外侧解剖型钢板内固定治疗股骨髁部粉碎性骨折及该部位术后骨不连、钢板断裂及感染病灶清除术后骨缺损33例。结果本组33例均获平均32(12~69)个月随访。骨折均愈合,平均愈合时间7.6(3~18)个月。无感染、内固定物松动、再骨折、免疫排斥反应等并发症发生。影像学资料示术后6个月异体骨板边缘变圆钝,异体骨板与宿主骨之间存在部分间隙,术后12个月异体骨板边缘进一步变薄、变圆,异体骨板两端与股骨之间间隙消失,可见边缘与宿主骨愈合征象。按Merchan等疗效评定标准进行膝关节功能评定:优16例,良12例,可4例,差1例,优良率84.8%。结论应用异体皮质骨板股骨内侧辅助固定结合外侧解剖型钢板内固定治疗股骨髁部粉碎性骨折,增加了股骨内侧的支撑力度,提高了固定的稳定性,术后可以早期膝关节功能锻炼,减少钢板的疲劳断裂。     

Evaluation of bone incorporation of patellar tendon autografts and allografts for ACL reconstruction using CT

Anterior cruciate ligament (ACL) reconstruction is a relatively common orthopedic procedure, with patellar tendon frequently a graft source. However, controversy exists regarding the decision to use autograft or allograft patellar tendon tissue. This experimental study used computed tomography (CT) to compare the percentage of bone graft incorporation following ACL reconstruction using autografts and allografts. Fifty consecutive patients undergoing ACL reconstruction were included in the study. The tibial bone plug was imaged with CT 1 week, 2 months, and 5 months postoperatively. Four images from each completed scan were analyzed for percentage of incorporation of the bone graft. The results of autograft and allograft incorporation for each of the time intervals were compared. No statistically significant difference was found in the amount of bone incorporation at the tibial bone plug 1 week, 2 months, and 5 months. Clinical concerns regarding slower or less complete healing of allograft bone tissue compared to autograft are not supported with regard to the grafts studied.     

A new algorithm to improve assessment of cortical bone geometry in pQCT

High-resolution peripheral quantitative computed tomography (HR-pQCT) is now considered the leading imaging modality in bone research. However, access to HR-pQCT is limited and image acquisition is mainly constrained only for the distal third of appendicular bones. Hence, the conventional pQCT is still commonly used despite inaccurate threshold-based segmentation of cortical bone that can compromise the assessment of whole bone strength. Therefore, this study addressed whether the use of an advanced image processing algorithm, called OBS, can enhance the cortical bone analysis in pQCT images and provide similar information to HR-pQCT when the same volumes of interest are analyzed. Using pQCT images of European Forearm Phantom (EFP), and pQCT and HR-pQCT images of the distal tibia from 15 cadavers, we compared the results from the OBS algorithm with those obtained from common pQCT analyses, HR-pQCT manual analysis (considered as a gold standard) and common HR-pQCT analysis dual threshold technique. We found that the use of OBS segmentation method for pQCT image analysis of EFP data did not result in any improvement but reached similar performance in cortical bone delineation as did HR-pQCT image analyses. The assessments of cortical cross-sectional bone area and thickness by OBS algorithm were overestimated by less than 4% while area moments of inertia were overestimated by ~ 5–10%, depending on reference HR-pQCT analysis method. In conclusion, this study showed that the OBS algorithm performed reasonably well and it offers a promising practical tool to enhance the assessment of cortical bone geometry in pQCT.     

Extracorporeal irradiation and incorporation of bone grafts: Autogeneic cortical grafts studied in rats

The incorporation of resected, extracorporeally irradiated (1, 5, 25 and 50 kGy) and orthotopically reim-planted autogeneic cortical bone was investigated in 116 adult Wistar rats. 7 mm-long diaphyseal segments of the tibia were resected, irradiated and re-implanted using K-wire osteosynthesis. Autogeneic fresh grafts served as controls. Graft healing was evaluated by radiography and histomorphometric study at 3, 6, 9, and 12 weeks. At 3 weeks, two thirds of the 50 kGy irradiated grafts were fractured and therefore the series with this dose was interrupted because of mechanical graft insufficiency. After 3 and 6 weeks there were no statistically significant differences among the control group and 1 or 5 kGy irradiated grafts. The healing of 25 kGy irradiated grafts was delayed from the sixth week onwards and continued until the end of the experiment at 12 weeks (50% reduction of incorporation). The incorporation of 1 and 5 kGy irradiated grafts showed a 16% (1 kGy) to 24% (5 kGy) delay at 12 weeks, compared to autogeneic fresh grafts. 1 and 5 kGy irradiated autogeneic bone grafts retain most of their biological potential. Resection, extracorporeal irradiation and reimplantation of bone tumors may therefore be a possible alternative to allografting.     

Autogenously vascularised bone allografts

Summary Conventional bone allografts carry a high incidence of complications such as infections and pseudarthroses due to immunological rejection and avascularity of grafts. In vascularised grafts healing and remodelling of bone is quicker and more complete. However, vascularised allografts need immunosuppression for prevention of rejection with vascular occlusion. Autogenously vascularised allografts are formed after implantation of bone in muscle of the recipient, allowing vascularisation from this muscle. A muscle-bone composite graft is thus obtained that can be transferred as a pedicled or free graft with microvascular anastomosis. In this study donors were DA and recipients Lewis rats. The bone grafts were implanted in the adductor muscles and transferred after 6 weeks into a femoral defect. A higher number of osteocytes were found in the autogenously vascularised group than in non-vascularised grafts. Creeping substitution was found in all cortical layers in vascularised grafts, whereas in conventional allografts bone resorption predominated. The experimental data suggest that in rat autogenously vascularised bone allografts show a remodelling pattern comparable with that of conventional vascularised bone autografts. The advantage of the autogenously vascularised bone allograft is that it allows transferral of a vascularised bone allograft together with its well-vascularised recipient bed without immunosuppressive treatment.     

Ageing patterns of trabecular and cortical bone and their relationship

Trabecular bone mass was measured in the iliac crest of 129 cadavera of both sexes with a physical method based on the principle of Archimedes. Cortical bone mass was measured at the second metacarpal of the right hand with a graphimetric X-ray method in 77 cases.Trabecular and cortical bone mass decreased significantly with age in women but not in men. A significant correlation between cortical and trabecular bone mass was established in women.

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Zusammenfassung Die trabeculäre Knochenmasse von 129 Leichen beiden Geschlechts wurde gemessen. In 77 Fällen wurde auch die corticale Knochenmasse gemessen. Die trabeculäre Knochenmasse von Beckenkammproben wurde mit einer physikalischen Methode bestimmt, welche auf dem Prinzip des Archimedes basiert. Die corticale Knochenmasse wurde am zweiten Metacarpus der rechten Hand mittels einer graphimetrischen Röntgenmethode gemessen.Die trabeculäre und die corticale Knochenmasse nahm bei Frauen, aber nicht bei Männern, mit zunehmendem Alter stark ab. Bei Frauen wurde eine signifikante Korrelation zwischen corticaler und trabeculärer Knochenmasse festgestellt.

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Résumé La masse de l'os spongieux de 129 cadavres des deux sexes a été déterminée. Dans 77 cas, la masse de l'os cortical est également mesurée. La masse de l'os spongieux d'os de la crête iliaque est établie à l'aide d'une méthode physique, basée sur le principe d'Archimède. La masse de l'os cortical est mesurée au niveau du second métacarpe de la main droite à l'aide d'une méthode graphimétrique aux rayons X.La masse de l'os spongieux et cortical décroit significativement avec l'âge chez la femme, mais non chez l'homme. Une corrélation significative a pu être établie chez la femme entre la masse de l'os cortical et spongieux.

     

Evidence that thymectomized, bone marrow-reconstituted rats do not reject their allografts

We have investigated the reasons why thymectomized, bone marrow-reconstituted (B) rats do not reject their allografts, by comparing the structure of inflammation and functions of inflammatory cells in nonrejecting allografts to rejecting allografts in normal control recipients. The results demonstrate that B recipients mount a specific cellular response towards the graft. The response in B recipients differs from that in normal controls by a smaller intensity of inflammation, fewer blast cells, and activated mononuclear phagocytes in the inflammatory infiltrate, as well as a delay in the appearance of specific donor-directed lytic activity in the graft. B rats also have fewer blast cells and an inverted CD4/8 ratio in the spleen. There is no obvious absence of any given cell type or cellular function in the graft inflammatory infiltrate. In light of these results no cell type responsible for allograft nonrejection can be pinpointed.     

Morphometric and physical investigations of segmental cortical bone autografts and allografts in canine ulnar defects.

Cortical bone grafts were implanted for six months in mature dogs using an osteoperiosteal 3-cm defect in the ulna to evaluate their respective morphometric and physical values compared with autografts. The bone-grafting material included fresh auto- and allografts, frozen and thimerosal preserved allografts, and partially demineralized bone allografts. The grafts were evaluated by roentgenograms, microradiograms, photon absorptiometry, porosity, fluorescence labeling measurements, and torsional loading at failure. Autografts achieved a better union score than the allografts, but intracortical bone porosity, percentage of cumulative new bone, and mineral apposition rate were not variables with statistical significance. Lamellar bone was found earlier and in greater quantity in autografts. Within the graft, new bone was deposited at a slower rate than in the recipient bone. Autografts showed less peripheral resorption and a greater torsional resistance than allografts. Photon absorptiometry demonstrated that nondemineralized allografts underwent a substantial loss of peripheral bone. This marked reduction in the outer diameter of the graft had more influence on torsional resistance than did the intracortical porosity of the graft. Demineralized allografts were osteoinductive in only 28% of the cases and appeared to respond in an all-or-nothing pattern. Frozen and thimerosal preserved allografts were the most acceptable substitutes to autografts.     

The incorporation of tibial allografts in total knee arthroplasty

Twelve knees in ten patients had revision total knee replacement with insertion of an allograft for a large tibial defect. The knees were retrospectively evaluated at an average of thirty-two months (range, twenty-five to fifty-one months) by clinical examination, radiography, planar bone scintigraphy, and single-photon-emission computed tomography. The average age of the patients was sixty-two years (range, fifty-four to seventy-nine years). A constrained total-condylar prosthesis was used for all revisions. A contained tibial defect was present in five knees, and seven knees had an uncontained defect that was treated with a massive composite structural allograft, five of which were secured with internal fixation. The knee scores improved from an average of 51 points before operation to an average of 87 points post-operatively. Seven knees had a score of 85 points or more and were considered to have an excellent clinical result. Two knees had a good result, with scores of 77 and 72 points. One knee had another revision because of painful non-union of a medial structural graft, and the result in that knee was considered a failure. The average range of motion improved from 84 degrees to 105 degrees. There were no deep infections, and no graft showed evidence of fracture or collapse. Radiographs demonstrated complete incorporation of the graft in eleven of the twelve knees at an average of twenty-three months after operation. Single-photon-emission computed-tomography scans showed uniform activity in the area of the graft in four of the five knees that were studied.     

Perforations of the gastrointestinal tract by a fish bone]

A brief of the literature dealing with perforations of the gastrointestinal tract at its different levels with fish bones is set forth. In recent 20 years the author has managed to collect 68 observations published in the home literature. 6 cases of the perforation of the duodenum, the small intestine, the ileum with injuries to the mesenteric vessels, resulting in massive bleeding, the caecum and the colon in the hepatic angle are presented. All the patients were operated upon. 2 patients died.     

脱钙冻干异体骨移植对骨缺损的修复作用

目的应用脱钙冻干异体骨（DFDBA）修复骨缺损，解决种植区的骨量不足问题。方法在种植外科中，将脱钙冻干异体骨用于19例种植区骨缺损患者，观察种植体动度、牙齿指数（GI）及x线改变等临床指标，评价其临床应用效果。结果19例植骨手术均获成功，无一例种植体周围炎发生，种植体初期稳定性良好。结论脱钙冻干异体骨既有一定的力学支持能力，又有骨诱导作用，且可塑性强。