Osteoclastic differentiation by mononuclear phagocytes containing biomaterial particles

Aseptic loosening of implant components is a common and important complication of both cemented and uncemented prosthetic joint replacements. Wear particles derived from organic polymer and metal implant biomaterials are commonly found within macrophages and macrophage polykaryons in the fibrous membrane between loose implant components and the host bone undergoing resorption. In order to determine whether biomaterial particle-containing, foreign-body macrophages may contribute to periprosthetic bone resorption, we cultured murine monocytes that had phagocytosed particles of biomaterials commonly employed in bone implant surgery [polymethylmethacrylate (PMMA), ultra-high molecular weight polyethylene (PE), titanium and chromium-cobalt] on bone slices and glass coverslips with UMR 106 osteoblast-like stromal cells in the presence of 1,25-dihydroxy-vitamin D₃. Under these conditions, all biomaterial particle-containing, foreign-body macrophages differentiated into osteoclastic cells, i.e. tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells capable of extensive lacunar bone resorption. This study shows that particle phagocytosis by macrophages does not abrogate the ability of these cells to undergo osteoclast differentiation. These findings emphasise the importance of the foreign-body macrophage response to biomaterial wear particles in the pathogenesis of aseptic loosening.     

Use of resorbable and screw fixation in pediatric craniofacial surgery

The concept of a rigid but nonpermanent method for bone stabilization for craniomaxillofacial surgery, particularly in infants and children, has long had theoretical appeal but a safe and effective method for bone fixation has been wanting. Since 1996, resorbable plate and screw systems have been available for clinical use. In this review, the author's technique and experience over the past 8 years for fixation of pediatric cranial vault deformities with one specific type of resorbable biomaterial, polylactic-polyglycolic acid copolymer (LactoSorb), biomaterial is described. The evolution of device use including conventional plate geometries, mesh panels, extended plate designs, threaded screws, push screws, and rivets is reviewed.     

Use of resorbable and screw fixation in pediatric craniofacial surgery

The concept of a rigid but nonpermanent method for bone stabilization for craniomaxillofacial surgery, particularly in infants and children, has long had theoretical appeal but a safe and effective method for bone fixation has been wanting. Since 1996, resorbable plate and screw systems have been available for clinical use. In this review, the author's technique and experience over the past 8 years for fixation of pediatric cranial vault deformities with one specific type of resorbable biomaterial, polylactic-polyglycolic acid copolymer (LactoSorb), biomaterial is described. The evolution of device use including conventional plate geometries, mesh panels, extended plate designs, threaded screws, push screws, and rivets is reviewed.     

组织工程在创伤骨科领域的研究进展

组织工程作为生命科学研究领域的一门崭新学科,其研究范围涉及骨、软骨、肌腱、神经、血管等多种组织的再造与修复,与创伤骨科的研究与治疗范围有非常大的交叉本文仅就组织工程在创伤骨科领域的研究进展,从骨、软骨、肌腱、血管等创伤骨科治疗中涉及较多的组织构建方面作一简要概述。     

Clinical applications of Trabecular Metal

Trabecular Metal (porous tantalum) offers a viable solution to several challenges in orthopedic reconstructive surgery, including monoblock acetabular cups, avascular necrosis intervention devices, and total hip reconstruction in situations of massive femoral bone loss. Porous tantalum approaches the ideal biomaterial: it is porous, strong, flexible, and biocompatible. For use in components for total hip arthroplasty, porous tantalum provides a substitute for lost bone, immediate bone loading, bone ingrowth, and soft-tissue attachment. It can be machine-shaped into custom designs in situations of massive bone loss.     

The role of polymethylmethacrylate bone cement in modern orthopaedic surgery

Polymethylmethacrylate remains one of the most enduring materials in orthopaedic surgery. It has a central role in the success of total joint replacement and is also used in newer techniques such as percutaneous vertebroplasty and kyphoplasty. This article describes the current uses and limitations of polymethylmethacrylate in orthopaedic surgery. It focuses on its mechanical and chemical properties and links these to its clinical performance. The behaviour of antibiotic-loaded bone cement are discussed, together with areas of research that are now shedding light upon the behaviour of this unique biomaterial.     

Trabecular metal in hip reconstructive surgery

Biological ingrowth surfaces have become a standard prosthetic element in reconstructive hip surgery. A material's properties, three-dimensional architecture, and surface texture all play integral parts in its biological performance. Trabecular metal is an important new biomaterial that has been introduced to enhance the potential of biological ingrowth as well as provide a structural scaffold in cases of severe bone deficit. Initial clinical applications have focused on bone restoration in tumor and salvage cases and in primary and revision reconstructive cases where the increased biological fixation would be of clinical benefit. The bone ingrowth potential and mechanical integrity of this material offer exciting options for orthopedic reconstructive surgeons.     

Assessment of bone graft substitutes in autopsy implant retrievals of the acetabulum in total hip arthroplasty

Two autopsy retrievals of acetabular reconstruction with different bone graft substitutes were analyzed. One patient underwent surgery with hydroxyapatite (HA) granules, and the other with demineralized bone chips. Incorporation occurred with the biomaterial bone-graft substitute HA primarily in the superior part of the acetabulum, where the HA was in contact with host cortical bone. No bony union occurred with the demineralized bone chips because of motion and migration of the acetabular cup. No bone incorporation of either bone-graft substitute was observed in the medial wall defects in both patients. There were two important findings: (1) the 3- to 8-mm depth and 70% to 75% surface of union of the HA bone graft substitute to host cortical bone was the same as seen with morselized, fresh-frozen bone graft; and (2) union of graft material to host bone was dependent on secure fixation of the acetabular construct.     

正颌外科技术联合应用Medpor矫正面中部塌陷

目的：研究Medpor在正颌外科中的应用。方法：对部分面中部塌陷的患者采用Medpor生物材料在梨状孔周围作衬垫，辅助正颌外科手术。结果：手术顺利，畸形纠正明显，均获得满意效果；外形恢复好，无感染等并发症。结论：Medpor生物材料可塑性强，选择适应证应用于正颌外科矫正面中部塌陷，具有创伤小、手术时间短、出血少的特点。     

Bone regeneration after enucleation of mandibular cysts: comparing autogenous grafts from tissue-engineered bone and iliac bone.

OBJECTIVE: The aim of this study was to compare bone regeneration after grafting enucleated mandibular cyst cavities using either autogenous osteoblasts cultured on a biomaterial or autogenous spongiose iliac bone. STUDY DESIGN: Twenty patients with 22 mandibular cysts were assessed. Eleven cysts were filled in with tissue-engineered bone (autogenous osteblasts cultured on demineralized bone matrix Osteovit) and 11 with spongiose iliac bone as controls. Panoramic radiographs were taken preoperatively, immediately postoperatively, and 3, 6, and 12 months after surgery. Radiolucency was computer analyzed using gray-level histograms. RESULTS: In both groups bone regeneration took place in a similar fashion. After 3 and 6 months there were few differences in bone density between the groups. However, in radiographic controls after 12 months ossification was considerably stronger in cysts grafted with tissue-engineered bone. CONCLUSION: These results advocate for the clinical application of tissue-engineered bone as an alternative viable filling material for cysts.     

Pathology of the bone-implant interfaces

Joint replacement surgery has a wide clinical application as a successful technique. However, the release of biomaterial in particulate form from various implant components has been implicated as a cause of two major clinical complications: 1) bone lysis with or without aseptic loosening, and 2) dissemination of wear particles to distant sites with adverse local or systemic cellular responses. This review focuses on the analysis of the clinical material obtained at the time of revision operations and its value in identifying the pathological processes taking place within the bone-implant microenvironment. Important issues discussed include the incidence of infection, characterization of wear particles, particle-cell interactions, local histopathological changes that lead to the formation of erosive inflammatory lesions next to the bone, sensitivity reactions, tumor formation, and the induction of inflammatory factors and cytokines that can influence the rate of bone resorption versus bone formation.     

The use of coral for cervical interbody arthrodesis (IBA) and vertebral body excision

Summary The value of using biomaterials and especially coral in cervical spinal surgery is linked to a desire to eliminate the disadvantages associated with the taking of bone grafts in arthrodeses. A chemical, microscopic, biomechanical and clinical study of coral from 1970 has shown the value of this material, whose structure resembles that of bone, and which degrades completely to be replaced by newly-formed bone. Our initial results in 20 cases confirmed these findings by studying the progress of the coral: its good clinical tolerance, and its excellent radiologic incorporation without modification of spinal statics. Subsequently 83 cases have ben treated with this biomaterial, of which 45 were followed up. The results are satisfactory from both the clinical viewpoint (technques of transdiscal osteophytectomy) and the biomechanical aspect.     

碳酸化羟基磷灰石水泥复合活性多肽修复骨缺损的研究

目的 通过动物实验观察碳酸化羟基磷灰石水泥复合活性多肽P19修复骨缺损的效果。方法 在10只杂种犬肱骨近端制作骨缺损动物模型，采用碳酸化羟基磷灰石水泥复合活性多肽P19修复骨缺损，并以单纯碳酸化羟基磷灰石水泥作为对照，在修复骨缺损后5d，4、8、12、16周处死动物，通过X线和组织学观察其修复效果。结果 实验组和对照组修复材料均能完全充填骨缺损，界面与骨组织结合紧密，生物相容性良好，随着植入时间的延长，实验组修复材料可逐渐降解并被新生骨爬行替代，而对照组降解和新生骨替代速度相对较慢。结论 碳酸化羟基磷灰石水泥是一种新型的骨缺损修复材料，活性多肽P19后可以促进碳酸化羟基磷灰石成骨和降解性能。     

Repair of porcine articular cartilage defect with a biphasic osteochondral composite.

Autologous chondrocyte implantation (ACI) has been recently used to treat cartilage defects. Partly because of the success of mosaicplasty, a procedure that involves the implantation of native osteochondral plugs, it is of potential significance to consider the application of ACI in the form of biphasic osteochondral composites. To test the clinical applicability of such composite construct, we repaired osteochondral defect with ACI at low cell-seeding density on a biphasic scaffold, and combined graft harvest and implantation in a single surgery. We fabricated a biphasic cylindrical porous plug of DL-poly-lactide-co-glycolide, with its lower body impregnated with beta-tricalcium phosphate as the osseous phase. Osteochondral defects were surgically created at the weight-bearing surface of femoral condyles of Lee-Sung mini-pigs. Autologous chondrocytes isolated from the cartilage were seeded into the upper, chondral phase of the plug, which was inserted by press-fitting to fill the defect. Defects treated with cell-free plugs served as control. Outcome of repair was examined 6 months after surgery. In the osseous phase, the biomaterial retained in the center and cancellous bone formed in the periphery, integrating well with native subchondral bone with extensive remodeling, as depicted on X-ray roentgenography by higher radiolucency. In the chondral phase, collagen type II immunohistochemistry and Safranin O histological staining showed hyaline cartilage regeneration in the experimental group, whereas only fibrous tissue formed in the control group. On the International Cartilage Repair Society Scale, the experimental group had higher mean scores in surface, matrix, cell distribution, and cell viability than control, but was comparable with the control group in subchondral bone and mineralization. Tensile stress-relaxation behavior determined by uni-axial indentation test revealed similar creep property between the surface of the experimental specimen and native cartilage, but not the control specimen. Implanted autologous chondrocytes could survive and could yield hyaline-like cartilage in vivo in the biphasic biomaterial construct. Pre-seeding of osteogenic cells did not appear to be necessary to regenerate subchondral bone.     

Use of mother of pearl as a bone substitute - Experimental study in sheep

Summary The authors present the first results of an experimental study using mother of pearl implants which were placed in the femur of sheeps. The aim of this study is to explore the possible applications of this new biomaterial for bone substitution in orthopaedic surgery. Radiologically it seems that there is extremely good acceptance of the implants in the host bone without mobilization, resorption or lysis of the peripheral bone and in all cases neotrabeculae in contact and in the neighbourhood of the implants. Histologically in the course of 3 months no sign of foreign body reaction were observed and the implants were not subject to biodegradation. By light microscopy osteogenic activity was detected within an osteoprogenitor cellular layer lining the implant resulting in a complete sequence of new bone formation. Nacre appeared to bind directly to new formed bone without intervening fibrous tissue. These preliminary results are extremely encouraging and they should be confirmed by the complete analysis of the sections corresponding to the longest follow-up. These results, combined with mechanical qualities of the mother of pearl implants allows us to hope that there are possible applications in orthopaedic surgery (blocks for intervertebral arthrodesis or for reconstruction in arthroplasty revisions, osteotomy wedges, butresses in recurrent shoulder and dislocation, screws for specific indications).     

Biomaterials in facial reconstruction

This review highlights some of the recent developments in biomaterials that are suited to reconstruction of the craniofacial skeleton. Although there is no ideal biomaterial, numerous alternatives are available to practicing surgeons that provide attractive alternatives to autogenous bone graft in the appropriate clinical settings. Biomaterials are a particularly well suited for skeletal augmentation, since autogenous bone can often undergo unpredictable resorption in these applications. Although all of the biomaterials reviewed in the present chapter seem to maintain their volume over time, porosity of the biomaterial may be a significant factor in determining bone ingrowth into the implant. Cement paste implants tend to contain micropores, and both experimental and clinical evidence indicates that there is less long-term bone ingrowth into these biomaterials than in implants with macroporous architecture.     

Behavior of natural coral in a human osteoporotic bone

The research concerning a preventive treatment of osteoporotic femoral neck started in 1990 because the surgical procedure of unstable femoral neck fractures is difficult, after effects frequent and there number will increase in the next decade. The goal is to reinforce the femur with a biomaterial. Natural coral is bioresorbable and biocompatible. It acts as an autologus bone graft in the reconstruction of either cortical or cancellous bone and increases the mechanical resistance. This work shows evidence of newbone formation in osteoporotic unbroken femur thanks to the biomaterial; consequently, there preventive surgical treatment should be taken in consideration.     

Influence of low-level laser therapy on biomaterial osseointegration: a mini-review

The aim of this paper is to provide an overview of the available literature on low-level laser therapy (LLLT) and its influence on bone repair and the osseointegration of biomaterials. Extensive studies of alveolar bone repair, a common problem in periodontal therapy, have been conduced worldwide. The utility of LLLT in biomaterial osseointegration is still unanswered, due to lack of literature and poorly understood mechanisms. It is still difficult for one to compare studies about the action of LLLT on the osseointegration of biomaterials because the experimental models and duration of treatments are very distinct. However, it could be concluded that LLLT may offer advantages in terms of periodontal and bone functional recovery and biomaterial osseointegration.     

生物材料生物相容性研究及在胸心外科的应用

良好的生物材料,可以替代人体自身相关组织或者器官,支持相应的机体功能,同时可以加速机体的自我修复和自愈过程.生物材料应用于临床,不仅需要具备与机体器官或组织相匹配的理化特性和生物力学性能,还应与机体组织具有良好的生物相容性和使用安全性.文章回顾了近年来生物材料及其生物相容性研究的某些进展以及在胸心外科领域的应用现状.