Different healing rates of bone autografts, syngeneic grafts, and allografts in an experimental rat model

Matching of donors and recipients for tissue antigens is vitally important for successful transplantation of essentially all organs and tissues, the major exception being bone. The importance of tissue-typing for the healing of bone allografts remains, however, a controversial issue as development of both humoral and cell-mediated immunity against the grafted bone has been observed in some experimental systems. In the present study, we compared the healing patterns of frozen antigen-mismatched allografts, frozen antigen-matched allografts (syngeneic grafts), and fresh cortical bone autografts in an experimental rat model. Histomorphometry of the graft-host interface revealed that new bone formation started significantly earlier in autografts than in allografts or syngeneic grafts. By 2 weeks, the level of new bone formation in the syngeneic grafts had reached that in autografts. Antigen-mismatched allografts, however, continued to exhibit a retarded formation of new bone throughout the union process. These histomorphometric observations were confirmed by molecular biologic analyses for the mRNA levles of type I collagen, which increased earlier and reached a higher level in autografts than in allografts. Use of syngeneic grafts resulted in a longer persistence of type I collagen mRNA expression in the healing tissue than in antigen-mismatched allografts. No apparent differences were seen between allografts and autografts in the expression of type III collagen. No cartilage-specific type JI collagen mRNA was observed, indicating that antigen-mismatching or preservation by freezing did not alter the basic mechanism of the interface healing process, although it did slow down the beginning of the process. The experiments suggest that a major antigen mismatch between donor and recipient affects the temporal gene expression of extracellular bone matrix and delays new bone formation at the graft-host interface of cortical bone allografts.     

A Bioactive Coating Enhances Bone Allografts in Rat Models of Bone Formation and Critical Defect Repair

Bone allografts are inferior to autografts for the repair of critical‐sized defects. Prior studies have suggested that bone morphogenetic protein‐2 (BMP‐2) can be combined with allografts to produce superior healing. We created a bioactive coating on bone allografts using polycondensed deoxyribose isobutyrate ester (PDIB) polymer to deliver BMP‐2 ± the bisphosphonate zoledronic acid (ZA) and tested its ability to enhance the functional utility of allografts in preclinical Wistar rat models. One ex vivo and two in vivo proof‐of‐concept studies were performed. First, PDIB was shown to be able to coat bone grafts (BGs). Second, PDIB was used to coat structural allogenic corticocancellous BG with BMP‐2 ± ZA ± hydroxyapatite (HA) microparticles and compared with PDIB‐coated grafts in a rat muscle pouch model. Next, a rat critical defect model was performed with treatment groups including (i) empty defect, (ii) BG, (iii) collagen sponge + BMP‐2, (iv) BG + PDIB/BMP‐2, and (v) BG + PDIB/BMP‐2/ZA. Key outcome measures included detection of fluorescent bone labels, microcomputed tomography (CT) quantification of bone, and radiographic healing. In the muscle pouch study, BMP‐2 did not increase net bone volume measured by microCT, however, fluorescent labeling showed large amounts of new bone. Addition of ZA increased BV by sevenfold (p < 0.01). In the critical defect model, allografts were insufficient to promote reliable union, however, union was achieved in collagen/BMP‐2 and all BG/BMP‐2 groups. Statement of clinical significance: These data support the concept that PDIB is a viable delivery method for BMP‐2 and ZA delivery to enhance the bone forming potential of allografts. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2278–2286, 2019     

Ankle arthrodesis with bone graft after distal tibia resection for bone tumors

BACKGROUND: Treatment of distal tibial tumors is challenging due to the scarce soft tissue coverage of this area. Ankle arthrodesis has proven to be an effective treatment in primary and post-traumatic joint arthritis, but few papers have addressed the feasibility and techniques of ankle arthrodesis in tumor surgery after long bone resections. MATERIALS AND METHODS: Resection of the distal tibia and reconstruction by ankle fusion using non-vascularized structural bone grafts was performed in 8 patients affected by malignant (5 patients) or aggressive benign (3 patients) tumors. Resection length of the tibia ranged from 5 to 21 cm. Bone defects were reconstructed with cortical structural autografts (from contralateral tibia) or allografts or both, plus autologous bone chips. Fixation was accomplished by antegrade nailing (6 cases) or plating (2~cases). RESULTS: All the arthrodesis successfully healed. At followup ranging from 23 to 113 months (average 53.5), all patients were alive. One local recurrence was observed with concomitant deep infection (a below-knee amputation was performed). Mean functional MSTS score of the seven available patients was 80.4% (range, 53 to 93). CONCLUSION: Resection of the distal tibia and arthrodesis of the ankle with non-vascularized structural bone grafts, combined with autologous bone chips, can be an effective procedure in bone tumor surgery with durable and satisfactory functional results. In shorter resections, autologous cortical structural grafts can be used; in longer resections, allograft structural bone grafts are needed.     

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.     

Allogenic versus autologous cancellous bone in lumbar segmental spondylodesis: a randomized prospective study

The current gold standard in lumbar fusion consists of transpedicular fixation in combination with an interbody interponate of autologous bone from iliac crest. Because of the limited availability of autologous bone as well as the still relevant donor site morbidity after iliac crest grafting the need exists for alternative grafts with a comparable outcome. Forty patients with degenerative spinal disease were treated with a monosegmental spondylodesis (ventrally, 1 PEEK-cage; dorsally, a screw and rod system), and randomly placed in two groups. In group 1, autogenous iliac crest cancellous bone was used as a cage filling. In group 2 the cages were filled with an allogenic cancellous bone graft. Following 3, 6, 9 and 12 months, the clinical outcome was determined on the basis of: the Oswestry Low Back Pain Disability Questionnaire; patient satisfaction; patient willingness to undergo the operation again; and a visual analog scale for pain. The radiological outcome was based on both fusion rate (radiographs, computed tomography), and on the bone mineral density of the grafts. After 6 months, the X-rays of the patients in group 2 had a significantly lower rate of fusion. Aside from this, there were no further significant differences. After 12 months, radiological results showed a similar fusion rate in both groups. Donor site complications consisted of five patients with hematoma, and three patients with persistent pain in group 1. No implant complications were observed. If a bone bank is available for support and accepting the low risk of possible transmission of infectious diseases, freeze–dried allogenic cancellous bone can be used for monosegmental spondylodeses. The results demonstrated an equivalent clinical outcome, as well as similar fusion rates following a 12-month period. This is in despite of a delayed consolidation process.     

Use of frozen cranial vault bone allografts in the repair of extensive cranial bone defects

Summary In cranioplasty complexity is proportional to the size of the defect, particularly if greater than 50 cm². If the patient's own bone flap is not available, allogenic frozen bone graft can be used instead.Between June 1990 and June 1995 twenty cranioplasties with allogenic frozen bone grafts were performed. Age of patients ranged between 23 and 63 years (average 38.4 years). Male/female ratio was 2 1.7. Size of craniectomy ranged between 65 and 150 cm² (average 83.3 cm²). Follow-up ranged between 10 and 58 months (average 41 months).Donors were tested to rule out transmissible diseases, infections, sepsis and/or cancer. Bone grafts were removed under aseptic conditions, microbiological cultures were taken, wrapped in a gauze soaked with Gentamicin sulphate and Bacitracin, sealed in three sterilised vinyl plastic bags, and stored in a deep freezer for a minimum of 30 days (range 36–93 days, average 67 days), at a temperature of –80 °C.Grafts were placed in the defect after a step was carved on its borders to facilitate the contact between host and graft. Vancomycin 1 g. IV/12 hours and Ceftriaxone 1 g. IV/12 hours were administered for five days.Grafts were covered by means of scalp flaps. Only one required a musculocutaneous free flap. None was exposed, extruded or had to be removed.Plain skull X-ray studies showed progressive remodelling of the grafts. Partial resorption was observed in two (2/20, 10%) and loss of thickness in another 3/20 (15%), but with no changes in the contour.Biopsies were taken in 3/20 (15%) cases at a second surgical procedure. Areas of osteoclastic resorptive activity mixed with others of osteoblastic bone apposition, showed replacement with new bone.We conclude that cranial vault frozen allografts are a good alternative to autologous bone when the latter is absent or not present in sufficient amount.     

自体椎板关节突柱状植骨融合治疗腰椎退行性疾病的疗效分析

[目的]通过与同种异体+自体骨融合比较,探讨术中整块切除椎板关节突裁制柱状植骨融合治疗退行性腰椎退行性疾病的临床疗效.[方法]对本院2008年10月～2011年11月采用术中整块切除椎板关节突裁制柱状植骨块与同种异体+自体骨融合治疗的62例腰椎退变患者进行回顾性分析,其中A组(椎弓根螺钉固定与自体柱状骨融合,自体柱状骨组)28例,B组(椎弓根螺钉固定与同种异体+自体骨融合,同种异体+自体骨组)34例,比较两种治疗方法在手术时间、术中出血量、手术切口大小、住院天数、手术费用、住院总费用等的差异.通过JOA评分、术后1年融合率等指标来评价两种治疗方法的疗效.[结果]术后随访20～35个月,平均26.3个月.A组与B组手术材料费和住院总费用比较有差异(P＜0.05),A组比B组少;两组患者在手术时间、术中出血量、手术切口、住院天数、术后1年融合率无明显差异(P＞0.05).两组患者术后各时间点JOA评分较术前比较有差异(P＜0.05),组间比较无明显差异(P＞0.05).A组未见明显并发症,B组术后有2例伤口周围红肿、白细胞升高及1例脑脊液漏.[结论]通过与同种异体骨+自体骨融合比较,术中整块切除椎板关节突裁制柱状椎体间植骨块作为植骨材料,植骨融合界面大,椎间融合率高,临床疗效好,是一种安全、方便、经济和实用的临床技术.     

Efficacy of different bone volume expanders for augmenting lumbar fusions

BACKGROUND: A wide variety of bone volume expanders are being used in performing posterolateral lumbar noninstrumented and instrumented lumbar fusions. This article presents a review of their efficacy based on fusion rates, complications, and outcomes. METHODS: Lumbar noninstrumented and instrumented fusions frequently use laminar autografts and different bone graft expanders. This review presents the utility of multiple forms/ratios of DBMs containing allografts. It also discusses the efficacy of artificial bone graft substitutes, including HA and B-TCP. Dynamic x-ray and/or CT examinations were used to document fusion in most series. Outcomes were variously assessed using Odom's criteria or different outcome questionnaires (Oswestry Questionnaire, SF-36, Dallas Pain Questionnaire, and/or Low Back Pain Rating Scale). RESULTS: Performing noninstrumented and instrumented lumbar posterolateral fusions resulted in comparable fusion rates in many series. Similar outcomes were also documented based on Odom's criteria or the multiple patient-based questionnaires. However, in some studies, the addition of spinal instrumentation increased the reoperation rate, operative time, blood loss, and cost. Various forms of DBMs, applied in different ratios to autografts, effectively supplemented spinal fusions in animal models and patient series. beta-Tricalcium phosphate, which is used to augment autograft fusions addressing idiopathic scoliosis or lumbar disease, also proved to be effective. CONCLUSIONS: Different types of bone volume expanders, including various forms of allograft-based DBMs, and artificial bone graft substitutes (HA and B-TCP) effectively promote posterolateral lumbar noninstrumented and instrumented fusions when added to autografts.     

Maintenance of interbody space in one- and two-level anterior cervical interbody fusion: comparison of the effectiveness of autograft, allograft, and cage

The use of allografts, autologous iliac crest grafts, and cages for anterior cervical fusion is well documented, however there is no comparison regarding the effectiveness of maintaining the interbody space with the three approaches. We retrospectively measured the rate and amount of interspace collapse, segmental sagittal angulations, clinical results, and radiographic fusion success rates to determine which is the best fusion material. We assessed 73 patients who had one- and two-level cervical discectomies and interbody fusions without instrumentation. The three groups had similar clinical results and fusion rates. However, in the autograft group union occurred in 4 months. In the allograft group, union did not occur until 5.54 months. Moreover, the loss of cervical lordosis (2.75 degrees) was less in the cage group than in the allograft group (9.23 degrees). Additionally, the anterior interspace collapse (1.73 mm) in the cage group was less than the collapse recorded in the autograft group (2.82 mm) and in the allograft group (4 mm). An interspace collapse of 3 mm or greater was observed in 56.1% of the patients in the allograft group, compared with only 19% of the patients in the cage group. We showed that the cage is superior to the allograft and autograft in maintaining cervical interspace height and cervical lordosis after one-level and two-level anterior cervical decompression procedures.Level of Evidence: Therapeutic study, Level III-2 (retrospective cohort study).     

Repair of long bone defects with demineralized bone matrix and autogenous bone composite

Background:

Repair of diaphyseal bone defects is a challenging problem for orthopedic surgeons. In large bone defects the quantity of harvested autogenous bone may not be sufficient to fill the gap and then the use of synthetic or allogenic grafts along with autogenous bone becomes mandatory to achieve compact filling. Finding the optimal graft mixture for treatment of large diaphyseal defects is an important goal in contemporary orthopedics and this was the main focus of this study. The aim of this study is to investigate the efficacy of demineralized bone matrix (DBM) and autogenous cancellous bone (ACB) graft composite in a rabbit bilateral ulna segmental defect model.

Materials and Methods:

Twenty-seven adult female rabbits were divided into five groups. A two-centimeter piece of long bone on the midshaft of the ulna was osteotomized and removed from the rabbits’ forearms. In group 1 (n=7) the defects were treated with ACB, in group 2 (n=7) with DBM, and in group 3 (n=7) with ACB and DBM in the ratio of 1:1. Groups 4 and 5, with three rabbits in each group, were the negative and positive controls, respectively. Twelve weeks after implantation the rabbits were sacrificed and union was evaluated with radiograph (Faxitron), dual-energy x-ray absorptiometry (DEXA), and histological methods (decalcified sectioning).

Results:

Union rates and the volume of new bone in the different groups were as follows: group 1 - 92.8% union and 78.6% new bone; group 2 - 72.2% union and 63.6% new bone; and group 3 - 100% union and 100% new bone. DEXA results (bone mineral density [BMD]) were as follows: group 1 - 0.164 g/cm², group 2 - 0.138 g/cm², and group 3 - 0.194 g/cm².

Conclusions:

DBM serves as a graft extender or enhancer for autogenous graft and decreases the need of autogenous bone graft in the treatment of bone defects. In this study, the DBM and ACB composite facilitated the healing process. The union rate was better with the combination than with the use of any one of these grafts alone.     

Anterior cervical fusion using dense cancellous allografts and dynamic plating

OBJECTIVE: Dense cancellous grafts provide an open matrix for vascular and cellular penetration for early osseous integration. Thus, they provide a better biological fusion substrate than cortical or corticocancellous grafts. The aim of this study is to evaluate the efficacy of the dense cancellous allografts as a substrate for anterior cervical fusion along with instrumentation. METHODS: This is a retrospective study of 98 patients who underwent anterior cervical discectomy, fusion with dense cancellous allograft bone, and instrumentation using dynamic plating between January 2001 and March 2002. Of these procedures, 60 involved single-level and 38 involved two-level fusions. Subsidence was assessed by plain x-rays at 1, 3, 6, and 12 months and fusion at 3, 6, and 12 months after surgery. Fusion was defined as the appearance of bridging trabecular bone and absence of motion in flexion-extension films. RESULTS: The mean follow-up period was 15 months (range, 12-25 mo). Successful fusion was observed in 70, 84, and 96% of the patients at 3, 6, and 12 months, respectively. The average subsidences for single-level and two-level fusions were 2.0 and 3.2 mm, respectively. No allograft- or hardware-related complications were encountered in our series. CONCLUSION: Dense cancellous allografts are very effective as bone graft substitutes for achieving anterior cervical fusion along with instrumentation. Successful fusion was observed in 70% of our patients at 3 months, with a fusion rate of 96% at 1 year. These allografts provide an effective replacement for autologous grafts in cervical interbody fusion.     

Fibula and tibia fusion with cancellous allograft vitalised with autologous bone marrow: first results for infected tibial non-union

Background and aims  Autogenous bone grafting has been used in reconstructing bone defects and in stimulating fracture healing, producing high healing rates in the treatment of infected tibial non-unions. A novel therapeutic alternative is now available known as “vitalised allograft”, a cancellous bone graft procured from femoral heads from living human donors and “vitalised” through the injection of autologous bone marrow. The aim of this study is to summarise the initial results of the fibula and tibia fusion using vitalised cancellous allograft in the treatment of infected tibial non-unions. Patients and methods  We initiated a follow-up of 15 prospective non-randomized patients who received a vitalised allograft in the treatment of infected tibial non-unions in order to produce bony union. The patients included 13 men and 2 women with an average age of 48 years. All patients received a multi-stage surgical approach. After establishing an infection-free environment, allogenic cancellous bone grafting was performed, intended as the final surgical procedure in fibula and tibia fusion. Our follow-up included a clinical and radiographic investigation of the calf in four planes. We analysed union-rate and time required for bony consolidation, as well as recurrent infections, re-fractures, potential graft-resorption, and time needed for graft and bone remodelling. Results  With an average follow-up of 17.1 months, infection control was obtained in 14 of 15 patients, producing an infection arrest rate of 93.3%. Radiographs indicated consolidation in 11 out of 15 cases, with a union rate of 73.3%. Bone union was achieved on average in 17.1 weeks. Conclusions  Fibula and tibia fusion with allogenic cancellous bone grafting, vitalised through autogenic bone marrow, could well become an innovative treatment option for infected tibial non-unions. We need, however, to analyse a higher number of cases over a longer follow-up period in order to assess more accurately recurrent infections and re-fractures.     

Donor site morbidity of calcaneal,distal tibial,and proximal tibial cancellous bone autografts in foot and ankle surgery. A systematic review and meta-analysis of 2296 bone grafts

PurposeThis study aims to report on the safety and donor site morbidity of the distal lower extremity (calcaneal, proximal, and distal tibial) cancellous bone autografts. We summarized the findings in a comprehensive infographic illustration. We are unaware of any similar meta-analyses to date.MethodsFollowing the PRISMA guidelines, two independent investigators searched MEDLINE (PubMed), EMBASE, SCOPUS, Google Scholar, and Cochrane databases in December 2020 using the following keywords and their synonyms: ("bone graft", "donor site morbidity", "calcaneal graft", “proximal tibia graft”, and “distal tibia graft”). Besides, the reference lists from previous review articles were searched manually for eligible studies. The primary outcomes of interest were (1) chronic pain, (2) fracture, and (3) infection, whereas the secondary outcomes were (1) neurological complications, (2) sensory disturbance and hypertrophic scars, (3) other complications such as shoe-wear difficulties and gait disturbance. Inclusion criteria were: studies on complications and adverse events of lower extremity bone autografts (calcaneal, proximal tibial, and distal tibial bone autografts) reporting at least one of the desired outcomes. Studies not reporting any of the outcomes of interest or if the full text is not available in English were excluded. Studies reporting on bone marrow aspirate or autografts for non-orthopedic indications were also excluded.ResultsAfter the removal of duplicates, a total of 5981 studies were identified. After screening those records, 85 studies remained for full-text assessment. Out of those, 15 studies qualified for the meta-analysis with a total of 2296 bone grafts. Out of those grafts, 1557(67.8%) were calcaneal grafts, 625 (27.2%) were proximal tibial grafts, and 114 (5%) were distal tibial grafts. In calcaneal bone grafts, there were 28 cases of chronic pain [1.97%, CI:1.10?2.50%, I² = 66%], 5 fractures [0.32%, CI: 0.10?0.60%,I² = 0%], 20 sural neuritis [1.28%, CI:0.70?1.80%, I² = 0%), and no wound infections. In proximal tibial grafts there were 13 cases of chronic pain [2.08%, CI: 1.01?3.2%, I² = 34.5%], 1 fracture [0.16%, CI:0.10?0.50%, I² = 0%], and 3 superficial wound infections [0.48%, CI: 0.10?1.01, I² = 0%]. In the distal tibial grafts there were no cases of chronic pain or wound infections, 1 fracture [0.90%, CI: 0.80?2.6%, I² = 0%], and 5 saphenous neuritis [4.5%, CI: 0.70?8.40%, I² = 65%].ConclusionCalcaneal, distal tibial, and proximal tibial bone autografts are safe with a low rate of overall and major complications. We report an overall complication rate of 6.8%, which is less than half of that previously reported for iliac crest grafts. The authors recommend using distal lower extremity grafts for foot and ankle primary surgeries instead of iliac crest grafts when indicated. Clinical trials with a large sample size are required.     

Inhibition of vessel allograft rejection by endothelial removal. Morphologic and ultrastructural changes.

The vascular endothelium plays an important and complex role in vascular allograft rejection. Antigens expressed by the endothelium can act to promote and be the target of rejection reactions, which often lead to thrombosis and ischemic necrosis of the allograft. In this study, segments of femoral artery and femoral vein with or without endothelium were grafted between allogenic or autologous control rats. Immunocompetent Lewis (RT1(1] recipient rats were randomly selected for groups (N = 14 for each) receiving the following: ACI- (RT1a) allografts with intact endothelium, allografts with endothelium removed before operation, autografts with endothelium, and autografts with endothelium removed. Rejection was assessed by graft patency as well as morphologic and ultrastructural changes. At 5 days, the allografts with intact endothelium were totally occluded, whereas allografts without endothelium remained patent, as did autologous control grafts with or without endothelium. Two additional groups (N = 14 each) receiving the de-endothelialized allografts or autografts were examined at 120 days after operation, revealing that grafts in both groups were still patent and had been re-endothelialized. These findings indicate that physical removal of vascular endothelium may depress vessel allograft rejection without immunosuppressive therapy.     

The effect of histocompatibility matching on canine frozen bone allografts

The value of histocompatibility matching in frozen bone allografts was studied in a canine cancellous ulnar segmental-replacement model. Frozen bone that was exchanged across strong and weak transplantation barriers was evaluated histologically and radiographically at thirteen and twenty-six weeks after grafting. Histological grading criteria quantified the type of union at each end of the graft and the degree of remodeling of the marrow, spongiosa, and compacta. Radiographic grading criteria included the presence of union at each end of the graft and the degree of remodeling of the graft segment. In vitro studies for serum antibody and cell-mediated immunity were carried out by isotopic cytotoxicity methods at seven intervals during the twenty-six-week study period. Histologically, the strong-barrier allografts had fewer osseous unions and less reorganization of spongiosa and marrow when compared with autograft controls at both thirteen and twenty-six weeks. Radiographically, the strong-barrier allografts at thirteen weeks had fewer unions and marked resorption of grafts material when compared with autograft controls. There were no differences between weak transplantation-barrier grafts and control autografts radiographically or histologically at thirteen and twenty-six weeks after grafting. Frozen bone allografts did not elicit detectable serum antibody or lymphocytes that were cytotoxic for donor cells.     

大段同种异体骨移植愈合的实验研究

目的　研究大段同种异体骨移植愈合过程和特点。方法　采用新西兰大白兔股骨中段切除 1 5cm骨干和骨膜实验动物模型。将 36只兔随机分成实验组和对照组。实验组植入深低温保存的同种异体骨 ,对照组植入自体新鲜骨 ,均用直径 3mm的髓内针固定。于术后第 1、 2、 3个月分别行X线摄片、ECT、大体标本、组织学观察 (四环素荧光标记、HE染色 )以及BMP免疫组织化学染色。结果　深低温保存的同种异体骨移植愈合与自体骨相似 ,ECT显示术后第 1个月骨代谢活跃 ,2、 3个月趋于稳定。移植骨BMP表达阴性 ,新生骨及其周围类基质表达阳性。其愈合是从宿主骨向移植骨 ,从周围向中央 ,从哈佛氏管向其四周逐渐进行爬行替代的过程。结论　同种异体骨移植愈合过程是移植骨全方位活化的过程 ,即全方位再血管化、新骨形成和宿主与移植骨接连的过程。其主要通过骨传导实现成骨 ,骨诱导亦发挥积极作用     

Osteogenesis after Bone and Bone Marrow Transplantation: II. The Initial Cellular Events Following Transplantation of Decalcified Allografis of Cancellous Bone

An experimental study was done in rabbits to investigate the fate of allogeneic iliac cancellous bone, both non-decalcified and decalcified with hydrochloric acid, transplanted to a muscular site for up to 14 days. Some of the treated allografts were impregnated with autologous bone marrow cells, obtained from the femoral medulla by aspiration, and each was compared with allografts alone. Combined myelo-osseous grafts produced bone after 7 to 8 days implantation, as did marrow autografts alone. In addition non-decalcified implants stimulated the production of multinucleated giant cells. Three different types of wash solution were used but these did not influence the cell population seen, nor the new bone formation. It is concluded that the critical events in bone formation after transplantation occur less than 8 days after the transplantation and that marrow cells have osteogenic capacity. This has relevance to the clinical aspects of bone grafting.     

Bovine bone grafting in occipito-cervical fusion for atlanto-axial instability in rheumatoid arthritis

Summary Bovine bone chips (Surgibone®) were used in occipito-cervical fusion in nine patients with atlanto-axial instability due to rheumatoid arthritis. The patients were examined with CT 12–15 months after surgery.Graft resorbtion was observed in one patient. The other 8 patients showed preserved grafts, in most cases the grafts appeared to be in contact with the underlying bone. One patient was revised, and at the grafted site a bony bridge was found.In conclusion, the use of bovine chips in posterior occipitocervical fusion will not lead to predictable bone union. However, there seem to be exceptions to that rule.     

Biomechanical properties of heat-treated bone grafts

Introduction A possible critical complication associated with banking bone is human immunodeficiency virus (HIV) infection. Recently, since the report of HIV infection in bone allografts from an HIV-seronegative donor, a more reliable method of sterilization for preserved bone graft has become necessary. Heat treatment of banking bone is one of the simple sterilization methods. This method is especially safe and practical for the prevention of HIV infection.Materials and methods We previously reported a biological study on heat-treated bone graft. In that study, we showed that revascularization and new bone formation of bone graft after heat treatment at 60°C was nearly the same as that of non-heat-treated bone graft, while at 100°C, revascularization and new bone formation showed a significant delay. This time, we examined the change of mechanical strength of heat-treated bone grafts after transplantation in an experiment. To eliminate the problem of antigenicity of grafted bone, we used autografts, not allografts. Two types of heat-treated autografts were employed: heat-treated at 60°C for 30 min and heat-treated at 100°C for 5 min; as a control, fresh autografts were replaced in the left femur of rabbits. A strength test was performed for both the transplanted bone and the untreated intact right femur with time after transplantation. The strength test consisted of a compression test and torsional test, and the strength was compared between transplanted bone and the untreated intact right femur.Results In the compression test, the grafts heat-treated at 60°C showed a strength ratio before transplantation of 97.3%. The strength ratio decreased to 63.5% at 18 weeks after transplantation. Then the strength ratio increased and recovered to 94.5% at 48 weeks after transplantation. However, the grafts heat-treated at 100°C showed unsatisfactory mechanical strength, at 48 weeks the strength ratio was 60.1%, which was significantly lower compared with controls. In the torsional test, the grafts heat-treated at 60°C showed almost the same strength observed in the compression test. However, the grafts heat-treated at 100°C showed unsatisfactory mechanical strength: at 48 weeks, the strength ratio was 57.3%.Conclusion Therefore, heat treatment at 60°C is a useful sterilization method, not only in biological but also mechanical terms.     

Osteogenesis after bone and bone marrow transplantation. II. The initial cellular events following transplantation of decalcified allografts of cancellous bone.

An experimental study was done in rabbits to investigate the fate of allogeneic iliac cancellous bone, both non-decalcified and decalcified with hydrochloric acid, transplanted to a muscular site for up to 14 days. Some of the treated allografts were impregnated with autologous bone marrow cells, obtained from the femoral medulla by aspiration, and each was compared with allografts alone. Combined myelo-osseous grafts produced bone after 7 to 8 days implantation, as did marrow autografts alone. In addition non-decalcified implants stimulated the production of multinucleated giant cells. Three different types of wash solution were used but these did not inftical events in bone formation after transplantation occur less than 8 days after tho the clinical aspects of bone grafting.