Subchondral defects in caprine femora augmented with in situ setting hydroxyapatite cement, polymethylmethacrylate, or autogenous bone graft: biomechanical and histomorphological analysis after two-years.

Juxta-articular defects pose significant challenges due to the high risk of fracture of the subchondral plate and articular cartilage. We evaluated the mechanical and histomorphological repair process of caprine subchondral femoral defects augmented with either a bioresorbable in situ setting hydroxyapatite cement (HAC), polymethylmethacrylate (PMMA), autogenous bone graft (AG), or left empty. Twelve-mm subchondral defects were made bilaterally in the medial femoral condyles of skeletally mature goats and augmented with a test material or left empty. Femurs were harvested at varying time periods out to 2 years and evaluated for subchondral stiffness and histomorphological indices. Several defects augmented using autograft or left empty sustained focal fracture of the subchondral plate. No HAC or PMMA augmented defects showed evidence of subchondral fracture. The HAC and PMMA augmented defects showed comparable stiffness at all time points. The mean volume fraction of HAC remaining within the defects progressively decreased from 96% at 24 h to 38% at 2 years. The new bone replacing the HAC appeared to have normal physiological architecture and orientation. In situ setting hydroxyapatite cement may be a viable alternative for the repair of subchondral defects with an important advantage that while undergoing gradual resorption and replacement with host bone, mechanical integrity of the skeletal defect is maintained.     

Application of a biphasic macroporous synthetic bone substitutes CERAFORM®: clinical and histological results

Missing bone is a challenging situation in orthopaedic surgery. Due to specific chemical and structural properties, biphasic ceramics are used as bone substitutes. We investigated intraoperative manoeuvrability, clinical tolerability, radiological and histological integration of a biphasic synthetic ceramic (CERAFORM^®). Present study reports 5-year follow-up of 43 cases requiring bone substitution: bone tumours; spinal fusions; revision arthroplasty; nonunions; fractures; osteitis. GESTO (Greffes ET Substitutes Tissulaires en Orthopedie) patient form was used for evaluation and follow up. Radiological survey was performed at 3, 6, 9, 12 and 18 months. We used CERAFORM^® as single substitute or mixed with allo- or autograft. Clinical and radiological integration occurred 9–12 months after implantation. Bone biopsy documented new bone formation. CERAFORM allows good filling of the defect, additional autograft or osteosynthesis is needed for higher mechanical stability. Radiological aspect after implantation stands for a rapid integration in the host bone. Histological examination confirmed bone remodelling.     

A systematic review of comparative studies on bone graft alternatives for common spine fusion procedures

Background

The increased prevalence of spinal fusion surgery has created an industry focus on bone graft alternatives. While autologous bone graft remains the gold standard, the complications and morbidity from harvesting autologous bone drives the search for reliable and safe bone graft substitutes. With the recent information about the adverse events related to bone morhogenetic protein use, it is appropriate to review the literature about the numerous products that are not solely bone morphogenetic protein.

Purpose

The purpose of this literature review is to determine the recommendations for use of non-bone morphogenetic protein bone graft alternatives in the most common spine procedures based on a quantifiable grading system.

Study design

Systematic literature review.

Methods

A literature search of MEDLINE (1946–2012), CINAHL (1937–2012), and the Cochrane Central Register of Controlled Trials (1940–April 2012) was performed, and this was supplemented by a hand search. The studies were then evaluated based on the Guyatt criteria for quality of the research to determine the strength of the recommendation.

Results

In this review, more than one hundred various studies on the ability of bone graft substitutes to create solid fusions and good patient outcomes are detailed.

Conclusion

The recommendations for use of bone graft substitutes and bone graft extenders are based on the strength of the studies and given a grade.     

Evolution of an in vivo bioreactor.

The ideal bone graft substitute requires osteoconductive, osteoinductive, and osteogenic components. This study introduces an "in vivo bioreactor," a model in which pluripotent cells are recruited from circulating blood to a vascularized coralline scaffold supplemented with bone morphogenetic protein-2 (BMP-2). The bioreactor generates new, ectopic host bone with the capability of vascularized tissue transfer. More importantly, bone is reproducibly formed in a closed and malleable environment. In a rat model, the superficial inferior epigastric vessels were isolated, ligated, and then threaded through a prefabricated coral cylinder (hydroxyapatite, ProOsteon 500). Experimental groups were characterized by the following variables: (1) with/without incorporation of vascular pedicle; (2) with/without addition of BMP-2 (0.02 mg/cm3). Scaffolds were harvested 6 weeks after implantation, embedded and sectioned. Tissue samples were decalcified, fixed, and stained with H&E, trichrome green, and CD31/PECAM-1 (a marker of endothelial cells). Vascularized coral scaffolds supplemented with BMP-2 presumably recruited circulating mesenchymal stem cells to generate bone. Bone formation was quantified through histological analysis, and reported as a percentage, area bone/area cross section scaffold x 100. Mean bone formation was 11.30%+/-1.19. All scaffolds supplied by the vascular pedicle, regardless of BMP-2 supplementation, demonstrated neo-vascular ingrowth. Scaffolds lacking a pedicle showed no evidence of vascular ingrowth or bone formation. This paper introduces a model of a novel "in vivo bioreactor" that has future clinical and research applications. The tissue engineering applications of the "bioreactor" include treatment of skeletal defects (nonunion, tumor post-resection reconstruction). The bioreactor also may serve as a unique model in which to study primary and metastatic cancers of bone.     

复合珊瑚羟基磷灰石人工骨的研制及其成骨效应

目的 自行研制复合珊瑚羟基磷灰石人工骨并评估其成骨效应。方法 取南海澄黄滨珊瑚碳酸钙在特定条件下经过“热液交换反应”，制成单纯珊瑚羟基磷灰石(coralline Hydroxyapatite，CHA)人工骨，并将其与基因重组骨形态发生蛋白(rhBMP2)和几丁糖复合制成了三种复合珊瑚羟基磷灰石(composite Coralline Hydroxyapatite，CCHA)人工骨，将此三种不同配型的复合人工骨和单纯CHA人工骨分别植入四组24只SD大白鼠肌肉内。手术后2、4、6、8周取材进行组织学观察，计数高倍单位视野内的成骨细胞数量和炎性细胞数量。采用SPSS8.0统计软件处理系统分析。结果 术后各时期取材结果显示：B组(CHA rhBMP2)和D组(CHA rhBM2P 几丁糖)的单位视野内成骨细胞数量明显多于A组(单纯CHA)和C组(CHA 几丁糖)：而C组和D组的单位视野内炎性细胞数量明显少于A组和B组。即D组人工骨的单位视野内的成骨细胞数量多、炎性细胞少。结论 rhBMP2-几丁糖／CHA复合人工骨不但具有显著的成骨诱导作用，还具有炎症反应轻及持续的诱导成骨作用，是一良好的骨移植替代物。     

Bone Graft Substitute Plug Failure With Giant Cell Reaction in the Treatment of Osteochondral Lesions of the Distal Femur: A Report of 2 Cases With Operative Revision

Although the treatment of symptomatic osteochondral lesions remains the focus of many orthopaedic clinicians, controversy remains regarding treatment choices and indications. Recently, the use of synthetic bone graft substitute composite plugs has been described to treat bone void lesions. We report 2 cases in which bone graft substitute plugs were used to graft bone defects in the knee and subsequently failed, requiring revision surgery. At revision arthroscopy, failure of incorporation was noted with foreign-body giant cells on histologic evaluation. Our technique for site debridement, revision bone grafting, and osteochondral resurfacing is presented.     

In vivo evaluation of calcium sulfate as a bone graft substitute for lumbar spinal fusion

BACKGROUND CONTEXT: Posterolateral fusions of the lumbar spine have nonunion rates as high as 35%. The availability of autologous bone to promote fusion is limited, particularly for multilevel fusions. Bone substitutes have been proposed to augment or replace autologous bone for spinal surgery. Calcium sulfate offers high porosity, osteoconductivity, and high resorption rate. This material has been used successfully for treatment of long bone defects but has not been investigated as a bone graft substitute for spinal fusions. PURPOSE: To determine whether the use of calcium sulfate granules in conjunction with an implantable electrical stimulator is a safe and effective means of attaining spinal fusion. STUDY DESIGN/SETTING: A rabbit lumbar fusion model was used to assess a calcium sulfate bone graft substitute in combination with electrical stimulation for spinal fusion. METHODS: Thirty-six adult New Zealand White female rabbits were divided into three groups. Each group underwent a single-level (L5-L6) fusion, receiving 3.0 cc calcium sulfate granules with bone marrow aspirate from the iliac crest. Group 1 had no electrical stimulator applied. Groups 2 and 3 received a 40-microA (Group 2) or a 100-microA (Group 3) implantable electrical stimulator. The animals were sacrificed at 8 weeks, and the rabbit spines were subjected to radiographic assessment, manual palpation, and mechanical testing. RESULTS: Two rabbits died postoperatively. The radiographic assessment revealed no fusions occurred at the adjacent nonoperated control levels (L4-L5). There were no fusions observed within Group 1, containing the calcium sulfate and bone marrow aspirate alone. The sites with the implantable stimulators showed a dose-dependent increase in fusion stiffness. However, no fusion mass in Group 2 or 3 was graded as bilaterally complete. CONCLUSION: This study found that calcium sulfate as a bone graft substitute was unsuccessful in promoting spine fusion in a rabbit model. There was radiographic evidence of rapid resorption of the calcium sulfate within 4 weeks after surgery. The use of electrical stimulation created a dose-dependent increase in mechanical competence of the bony mass. However, the addition of direct current (DC) current did not significantly alter fusion rates with calcium sulfate used as the bone graft substitute in this model.     

自体骨移植与骨替代物手术治疗胫骨平台骨折的Meta分析

目的：通过Meta分析系统评价自体骨移植和骨替代物治疗胫骨平台骨折的临床疗效。方法：计算机检索2005年1月至2022年8月PubMed、Web of Science、中国知网、万方等数据库已发表的关于自体骨移植和骨替代物治疗胫骨平台骨折的病例对照研究文献。根据纳排标准进行文献筛选及数据提取,对入选的随机对照研究（randomized controlled trial,RCT）采用Cochrane手册中的干预性Meta分析标准进行质量评价。采用RevMan 5.3软件对两种方法的关节凹陷、关节面二次塌陷率、失血量、手术时间和感染率进行Meta分析。结果：共纳入7项RCT研究,424例患者,其中骨替代物组296例,自体骨移植组128例。两组手术时间[MD=-16.79,95%CI(-25.72,-7.85),P=0.000 2],出血量[MD=-70.49,95%CI(-79.34,-61.65),P<0.000 01]比较,差异有统计学意义。而关节凹陷[MD=-0.17,95%CI(-0.91,0.58),P=0.66],关节面二次塌陷率[RR=-0.74,95%CI(0.35,...     

Perioperative complications with rhBMP-2 in transforaminal lumbar interbody fusion

Bone morphogenetic protein (BMP) is commonly used as an ICBG substitute for transforaminal lumbar interbody spine fusion (TLIF). However, multiple recent reports have raised concerns regarding a substantial incidence of perioperative radiculopathy. Also, given the serious complications reported with anterior cervical BMP use, risks related to swelling and edema with TLIF need to be clarified. As TLIF related complications with rhBMP-2 have generally been reported in small series or isolated cases, without a clear denominator, actual complication rates are largely unknown. The purpose this study is to characterize perioperative complications and complication rates in a large consecutive series of TLIF procedures with rhBMP-2. We reviewed inpatient and outpatient medical records for a consecutive series of 204 patients [113 females, 91 males, mean age 49.3 (22–79) years] who underwent TLIF using rhBMP-2 between 2003 and 2007. Complications observed within a 3-month perioperative interval were categorized as to etiology and severity. Wound problems were delineated as wound infection, hematoma/seroma or persistent drainage/superficial dehiscence. Neurologic deficits and radiculopathies were analyzed to determine the presence of a clear etiology (screw misplacement) and identify any potential relationship to rhBMP-2 usage. Complications were observed in 47 of 204 patients (21.6%) during the 3-month perioperative period. Major complications occurred in 13 patients (6.4%) and minor complications in 34 patients (16.7%). New or more severe postoperative neurologic complaints were noted in 13 patients (6.4%), 6 of whom required additional surgery. These cases included one malpositioned pedicle screw and one epidural hematoma. In four patients (2.0%), localized seroma/hematoma in the area of the foramen caused neural compression, and required revision. In one additional patient, vertebral osteolysis caused foraminal narrowing and radiculopathy, but resolved without further surgery. Persistent radiculopathy without clear etiology on imaging studies was seen in six patients. Wound related problems were seen in six patients (2.9%), distributed as wound infection (3), hematoma/seroma (1) and persistent drainage/dehiscence (2). Overall, this study demonstrates a modest complication rate for TLIF using rhBMP-2. While perioperative complications which appeared specific to BMP usage were noted, they occurred infrequently. It will be necessary to weigh this incidence of complications against the complication rate associated with ICBG harvest and any differential benefit in obtaining a solid arthrodesis.     

Evaluation of ABM/P-15 versus autogenous bone in an ovine lumbar interbody fusion model

A prospective, randomized study was performed in an ovine model to compare the efficacy of an anorganic bovine-derived hydroxyapatite matrix combined with a synthetic 15 amino acid residue (ABM/P-15) in facilitating lumbar interbody fusion when compared with autogenous bone harvested from the iliac crest. P-15 is a biomimetic to the cell-binding site of Type-I collagen for bone-forming cells. When combined with ABM, it creates the necessary scaffold to initiate cell invasion, binding, and subsequent osteogenesis. In this study, six adult ewes underwent anterior-lateral interbody fusion at L3/L4 and L4/L5 using PEEK interbody rings filled with autogenous bone at one level and ABM/P-15 at the other level and no additional instrumentation. Clinical CT scans were obtained at 3 and 6 months; micro-CT scans and histomorphometry analyses were performed after euthanization at 6 months. Clinical CT scan analysis showed that all autograft and ABM/P-15 treated levels had radiographically fused outside of the rings at the 3-month study time point. Although the clinical CT scans of the autograft treatment group showed significantly better fusion within the PEEK rings than ABM/P-15 at 3 months, micro-CT scans, clinical CT scans, and histomorphometric analyses showed there were no statistical differences between the two treatment groups at 6 months. Thus, ABM/P-15 was as successful as autogenous bone graft in producing lumbar spinal fusion in an ovine model, and it should be further evaluated in clinical studies.     

Effect of Hydroxyapatite porous characteristics on healing outcomes in rabbit posterolateral spinal fusion model

Hydroxyapatite (HA) has been commonly used as a bone graft substitute in various kinds of clinical fields. To improve the healing capability of HA, many studies have been performed to reveal its optimal structural characteristics for better healing outcomes. In spinal reconstruction surgery, non-interconnected porous HAs have already been applied as a bone graft extender in order to avoid autogenous bone harvesting. However, there have been few experimental studies regarding the effects of the structural characteristics of HA in posterolateral lumbar intertransverse process spine fusion (PLF). The aims of this study were to investigate the effect of HA porous characteristics on healing outcomes in a rabbit PLF model in order to elucidate appropriate structural characteristics of HA as a bone graft extender. Thirty-six adult female Japanese White rabbits underwent bilateral intertransverse process fusion at the level of L5–6 without internal fixation. We prepared three types of HA with different porosities: HA with 15% porosity (HA15%), HA with 50% porosity (HA50%), and HA with 85% porosity (HA85%), all of which were clinically available materials. The HA15% and HA50% had few interconnecting pores, whereas the HA85%, which was a recently developed material, had abundant interconnecting pores. All rabbits were randomly divided into the following four groups according to the grafted materials: (1) HA15% + autogenous bone, (2) HA50% + autogenous bone, (3) HA85% + autogenous bone, (4) pure autogenous bone graft. The animals were euthanized at 5 weeks after surgery, and post-mortem analyses including biomechanical testing, radiographical and histological evaluations were performed. There was no statistically significant difference in either fusion rate and/or bending stiffness among the three HA groups. However, in histological and radiological analyses, both bone ingrowth rate and direct bone bonding rate in the HA85% group were significantly higher than those in the HA15% and HA50% groups, despite the similar value of bone volume rate in fusion mass among the three HA groups. In the HA85% group, bone ingrowth was achieved throughout the implanted HAs via interconnecting pores and there was excellent unification between the HA granules and the newly mineralized bone. On the other hand, in the non-interconnected porous HA groups, only a little bone ingrowth could be seen at the peripheral pores of the implanted HA, and its surface was mostly covered with fibrous tissue or empty space. The current study demonstrated that the HA porous characteristics had an effect on the histological outcomes in a rabbit PLF model. We would like to conclude that the interconnected high porous structure seems to be promising for the environment of PLF in the point of producing fusion mass with higher cellular viability. This is because the HA85% is superior in terms of integration with the newly formed bone in fusion mass compared to the non-interconnected porous HAs. However, the porous modifications of HA have little influence on fusion rate and mechanical strength because primary stabilization of the fusion segment is mainly achieved by bridging bone between the adjacent transverse processes outside the implanted materials, rather than the degree of integration between the newly formed bone and the HA granules in PLF.     

Is there still an indication for bovine xeno-graft in human orthopaedic and trauma surgery?

Summary The author has studied 21 cases of bovine xeno-grafts in human orthopaedic and trauma surgery. The indications were benign tumours (filling of defects with or without structural support), osteotomies for lengthening or passive correction of the limb (support and filling of defects), tibial tubercle elevation and some trauma cases, particularly complex fractures of the lateral tibial plateau. The study showed a lack of graft resorption, no matter the site of implantation. The graft was more or less incorporated according to the site. It incorporated well in the traumatised epiphysis, incompletely in short or flat bones and in the metaphyseal zone, and poorly in the diaphysis. Histological studies were made of 2 cases with follow-up of 2 and 5 years. They both showed a fibrous interface, discrete graft resorption with no sign of consolidation. Without considering the risks of contamination (prion or other), the author rejects this type of graft from a biological view point. Out of the 21 cases, we can however confirm the good mechanical hold of the bovine xenografts, whatever their site of implantation. In conclusion, it seems that the only and rare indications which remain are purely mechanical in the attempt to substitute bone which could add mechanical qualities which are sometimes necessary for good biological results with bone substitutes in osteosynthesis.     

Bony allografts and prosthetic replacement of the acetabular aspect of the hip

Summary 51 cases of repeat hip replacement have been reviewed, using allografts for acetabular bone loss, stages 2 and 3 (27 lyophilised and 24 deep-frozen). Mean follow-up was 4 years. Loosening was the reason for intervention; 14% of cases were septic. Massive grafts were used in 75% of cases and smaller grafts in 25% of cases. In addition a reinforcement ring was necessary in 75% of cases. Merle d'Aubigné's rating scale was used to assess results. The radiologic assessment score was that of Gross and De Lee.There was no difference between lyophilised and deep-frozen grafts. Clinical scores found 55% of excellent results; 11% were poor, the rest were good or fair. Stability was more troublesome than pain. Radiologic screening showed union between graft and host in 53% of cases but in 41% there was incomplete fusion. In the non-weight-bearing area bone lysis appeared in 14 cases out of 20. Five cases were complete failures; four of these were infected and were reoperated, the bone-graft acting as a foreign body.To date, we have no better bone replacement material than allografts. Fixation of the graft must be secure. An infected hip is not a good indication for this type of operation. Clinical results are satisfactory in more than 80% of cases, although 40% of grafts seem to be incompletely integrated.     

Biomechanical studies of transthoracic vertebral body replacement with autologous bone grafts (fibula and rib)

Thoracic processes which destroy vertebral bodies leave gaps which usually have to be bridged. The aim of our experiments was to find out whether rib and fibula grafts are suitable vertebral body substitutes from the biomechanical point of view. Therefore, we examined characteristics of vertebral body/bone graft/vertebral body arrangements under the influence of pulsating compression forces in a testing machine. The deformation of the rib graft alone was 0.78 mm under a preselected peak load of 1010 Newton. When the rib graft was placed between two vertebral bodies, the deformation (creeping) was 6 mm under a peak load of 1010 Newton. The deformation of the fibula graft alone was 0.41 mm, and when placed between vertebral bodies maximally 3 mm. The results of our experiments lead to the conclusion that ribs modified according to our design are prinzipally suitable for vertebral body replacement in the thoracic region as far as primary stress resistance is concerned. Characteristics of these bone grafts in the human body are being followed-up.     

Lumbar spinal fusion with β-TCP granules and variable Escherichia coli–derived rhBMP-2 dose

Background contextThe ideal tissue-engineered solution for any bone graft substitute is to assist in the rapid formation of bone and facilitate fusion.PurposeThe present study aims to evaluate this E-BMP-2 (Escherichia coli–derived human bone morphogenetic protein-2) in ovine posterolateral lumbar fusion (PLF) to examine the influence of dose and overall performance in a model with similar graft size and diffusive challenges to the human.Study design/settingIn vivo large animal model study.MethodsAn adult ovine PLF was performed in 30 animals with groups of E-BMP-2 with a beta-tricalcium phosphate (β-TCP) carrier at three different dosages, β-TCP alone, and autograft from the iliac crest. The fusions were assessed by radiography (X-ray and microcomputed tomography), mechanical testing, and hard-tissue histology with bone labels at 6, 8, and 10 weeks along with routine paraffin histology at 12 weeks.ResultsResults showed increasing new bone and fusion rate with E-BMP-2 dose, whereas β-TCP alone was largely resorbed and did not achieve fusion in this model at 12 weeks. Autograft showed similar grading for the amount of bone between the transverse processes but a lower fusion rate than β-TCP/E-BMP-2 groups. Bone labels revealed new bone formation at all time points for the E-BMP2 groups, whereas the autograft group showed active bone formation at 10 weeks. Beta-tricalcium phosphate displayed reliable incorporation into the decorticated host bone, whereas limited new bone was found between the transverse processes. At the center of the fusion mass, increased E-BMP-2 dose led to increased incorporation of β-TCP by new bone.ConclusionsThese results suggest that E-BMP-2 was capable of producing posterolateral fusion in the ovine model that is equal to or superior to autologous graft in terms of fusion rate and mechanical strength. E-BMP-2 dose had considerable influence on β-TCP granule resorption.     

Comparison of three techniques of anterior fusion in single-level cervical disc herniation

This study compared the clinical and radiographic outcome of three techniques of anterior fusion for cervical disc herniation: Cloward fusion with autograft, Cloward fusion with freeze-dried bone, and BAK-C device fusion. In a cohort of 84 consecutive patients, 34 were treated by classic autograft Cloward’s technique, in 26 patients freeze-dried xenograft Surgibone was used and in the last 24 patients a BAK-C titanium device was implanted. The mean follow-up period of this last group was 14.6 months. All patients were operated by the same surgeon at the same hospital and all underwent single-level surgery. Results were evaluated on the basis of patient satisfaction and postoperative capacity to work. There was no significant difference between the three groups related to the preoperative assessment. The analysis revealed that BAK-C patients had significantly shorter hospital stays. No postoperative cervical collar was worn by BAK-C patients and they had the highest percentage of excellent clinical results. Concerning radiographic evaluation, BAK-C achieved a more stable fixation of the involved segment without complications in contrast with the two others, which presented a significant incidence of extrusion, collapse, kyphosis and pseudarthrosis. Measurement of the progressive kyphosis grade shows statistically significant differences between the three groups. BAK-C patients had the lowest kyphosis grade at the end of the follow-up. There is an important correlation between collapse, collapse with kyphosis and pseudarthrosis with bad clinical results. In conclusion, the BAK-C device showed significant advantages, including higher patient satisfaction, unnecessary postoperative collar, early rehabilitation and a lower rate of complications. Furthermore, BAK-C is cost effective because of it shortens postoperative hospital stay and allows an earlier return to work. Received: 9 March 1998 Revised: 21 August 1998 Accepted: 25 August 1998     

Demineralized Bone Matrix Injection in Consolidation Phase Enhances Bone Regeneration in Distraction Osteogenesis via Endochondral Bone Formation

Background

Distraction osteogenesis (DO) is a promising tool for bone and tissue regeneration. However, prolonged healing time remains a major problem. Various materials including cells, cytokines, and growth factors have been used in an attempt to enhance bone formation. We examined the effect of percutaneous injection of demineralized bone matrix (DBM) during the consolidation phase on bone regeneration after distraction.

Methods

The immature rabbit tibial DO model (20 mm length-gain) was used. Twenty-eight animals received DBM 100 mg percutaneously at the end of distraction. Another 22 animals were left without further procedure (control). Plain radiographs were taken every week. Postmortem bone dual-energy X-ray absorptiometry and micro-computed tomography (micro-CT) studies were performed at the third and sixth weeks of the consolidation period and histological analysis was performed.

Results

The regenerate bone mineral density was higher in the DBM group when compared with that in the saline injection control group at the third week postdistraction. Quantitative analysis using micro-CT revealed larger trabecular bone volume, higher trabecular number, and less trabecular separation in the DBM group than in the saline injection control group. Cross-sectional area and cortical thickness at the sixth week postdistraction, assessed using micro-CT, were greater in the regenerates of the DBM group compared with the control group. Histological evaluation revealed higher trabecular bone volume and trabecular number in the regenerate of the DBM group. New bone formation was apparently enhanced, via endochondral ossification, at the site and in the vicinity of the injected DBM. DBM was absorbed slowly, but it remained until the sixth postoperative week after injection.

Conclusions

DBM administration into the distraction gap at the end of the distraction period resulted in a significantly greater regenerate bone area, trabecular number, and cortical thickness in the rabbit tibial DO model. These data suggest that percutaneous DBM administration at the end of the distraction period or in the early consolidation period may stimulate regenerate bone formation and consolidation in a clinical situation with delayed bone healing during DO.     

生物活性复合人工骨的制备与理化性能研究

目的探讨硫酸钙/骨基质明胶生物活性复合人工骨的制备方法及其理化性能。方法分别制备硫酸钙、骨基质明胶颗粒,按1：1、2：1、3：1、1：0不同质量比例制备复合人工骨。经扫描电镜观察、生物力学测试及体外降解试验,研究不同配比复合人工骨的结构特征、力学强度及降解速率。结果硫酸钙与骨基质明胶呈均匀混合分布,材料内见较多孔径为100～500μm的微孔结构,孔隙间相互交通,随着骨粒含量的增加,孔径逐渐增大。质量比为1：1、2：1、3：1、1：0的复合人工骨的抗压强度分别为(3．53±0．62)、(6．74±0．78)、(13．60±1．01)、(39．85±2．33)MPa,100%体外降解时间分别为8、10、12、12周。结论硫酸钙/骨基质明胶复合人工骨具有利于新骨长入的微孔结构,随着骨粒含量的增高,材料的力学强度逐渐减低,降解时间加快,不同配比的复合材料可适用于不同的植骨需要。