ISSN:0885-9698    

出版商:OVID    

年代:1993

数据来源: OVID

ISSN:0885-9698    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Summary:Metallic devices have been used successfully by the orthopaedic community for stabilization of fractures and more recently for total joint replacement. The metals used are alloys involving several elements. These alloys were not developed by the medical industry but have been adopted by them because of strength, corrosion resistance, and biocompatibility. In general, the materials are well accepted. However, there is concern because of the recognition that metal is released from the implant into the peri-implant tissue and then is transported to distant sites in the body. Some of the metals are known to be causes of contact dermatitis in the normal human population, and some of them in special forms have been associated with carcinogenicity. Nevertheless, the devices have functioned well without major consequences. It remains important to use the best materials available, to insert them correctly, and to minimize situations that will lead to wear, corrosion, and deposition of particulate debris or ions into the tissue.

ISSN:0885-9698    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Summary:In vivo, autopsy, and clinical studies have shown that bulk cement or polymethylmethacrylate appears to be very well tolerated and does not appear to induce a significant foreign body reaction. Examination of autopsy material shows no adverse effect on human endosteal bone, and osseo-integration can and does occur. Long-term clinical studies support these conclusions and clearly demonstrate the importance of technique when using surgical bone cement. Fragmentation of bone cement results in the generation of particulate debris, which is phagocytosized by macrophages. Either through cell activation or cell injury, a variety of enzymes, prostaglandins, and cytokines, capable of stimulating osteoclasts, resulting in bone resorption, are released. Also, there is new evidence that suggests “activated macrophages” may play a direct role in bone resorption.

ISSN:0885-9698    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Summary:It is now well established that the major long-term complication after total joint replacement (TJR) is aseptic loosening of the prosthetic components. This problem, although initially described in subjects with components secured in bone with methacrylate cement, has also been recognized in patients who have undergone TJR using noncementing techniques. The relative roles of so-called “mechanical” and “biological” factors in the pathogenesis of implant loosening have been extensively examined, and it is now generally accepted that this process is indeed multifactorial. Dissecting the individual roles and interplay of mechanical, biomaterial, and biological events in the pathogenesis of implant loosening is of critical importance in developing new strategies to reduce the incidence of this complication. This review will focus on the role of paniculate debris generated from prosthetic materials and its role in the pathogenesis of peri-implant osteolysis and implant loosening.

ISSN:0885-9698    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Summary:The process of ultrahigh molecular weight polyethylene (UHMW-PE) breakdown, started at the articular surface of the cup, continues in small fragments after generation. An assiduous interaction between the UHMW-PE particles and the host cells leads to oxidative changes of the UHMW-PE and to size reduction of the particles simultaneous with transporting them toward, and finally by, lymphatic or blood vessels. The particles are mobilized by means of enzymatic, extracellular matrix-degrading activity of cells that have phagocytosed them or adhered to them. Together, these characteristics indicate an attempt by the natural cellular immunity system to eliminate the implant wear debris. Macrophages are the main effector cells acting as scavengers; however, excessive amount of the wear debris evokes phagocytic activity of cells other than macrophages as well.

ISSN:0885-9698    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Summary:Kinematic characteristics of the knee joint after total knee arthroplasty produce adverse wear conditions at the articular bearing surface. Some implant materials and designs that are currently in use have addressed these issues, but a few problems remain. Polyethylene quality and particulate debris are major concerns that have yet to be resolved, but implant design characteristics can minimize the impact of wear on the clinical course.

ISSN:0885-9698    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Summary:Because of clinical success, total hip arthroplasty (THA) is being performed increasingly in a younger, more active population. Given the cumulative activity of these patients, the wear characteristics of the prosthetic components take on greater importance. Additionally, because the wear of components generates biologically active particles with an inflammatory potential, wear essentially determines the life span of total joint replacement devices. The solutions to this clinical problem thus depend on controlling the production and dissemination of particulate wear debris to the joint space and implant interfaces.

ISSN:0885-9698    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Summary:The role of ceramic materials in joint reconstruction is explored. Ceramic materials in use are defined in terms of chemical composition, mechanical properties, tribological properties, and biocompatibility. The prime materials for structural applications such as joint bearing surfaces are alumina, A12O3, and zirconia, ZrO2. The bone-prosthesis interface in uncemented prostheses may undergo significant improvement through osseo-integration with the use of bioactive ceramic coatings. Both applications of ceramic materials should be approached cautiously until clinical data demonstrate efficacy.

ISSN:0885-9698    

出版商:OVID    

年代:1993

数据来源: OVID

ISSN:0885-9698    

出版商:OVID    

年代:1993

数据来源: OVID