摘要:

AbstractMetallurgical and histological examinations of implants and adjacent tissue removed from orthopedic patients have been performed in a series of 190 cases. The results have been correlated with clinical findings where possible. The two major factors to emerge from this study were that many stainless steel implants corrode in the body and that titanium implants release titanium into the local tissue, which may become discolored.Severe cases of corrosion in stainless steel implants were attributed to faulty manufacturing technique and poor implant usage. This corrosion was frequently associated with crystal‐like “microplates” in the tissue and lead to clinically significant effects in some cases. Less severe cases of corrosion were almost invariably associated with interfaces between components. Susceptibility to this corrosion may be minimised by improvements in design and materials specification.Titanium levels in excess of 2,000 ppm were found in the tissue in 3 cases out of 19 analysed, no specimen of a control series showing greater than 100 ppm. Histological sections showed accumulations of intracellular particles of exogenous origin. The evidence that such titanium release and particle accumulation causes clinically significant effects is only minimal but it is possible that systemic distribution of titanium and remote hypersensitivity effects could

ISSN:0021-9304    

DOI:10.1002/jbm.820080303

出版商:John Wiley&Sons, Inc.    

年代:1974

数据来源: WILEY

摘要:

AbstractTissues from around surgical implants have been examined by optical microscopy and electron microscopy and by electron diffraction and x‐ray spectrographic techniques. The presence of small alloy fragments and carbides worn from cobalt‐chromium total joint replacements was confirmed. These foreign bodies had been phagocytosed by macrophages and there were no indications that the tissues were damaged by their presence. In 13 of 44 specimens there were granulomatous foci related apparently to the presence of numerous minute particles of unknown composition which had elicited vigorous macrophage reactions.In tissues near stainless steel joints too there were particles of the naked alloy taken up by macrophages and again the fibrous tissue appeared unaffected.Typically the tissues near to stainless steel implants are affected by cytosiderosis. It is deduced that the iron released by corrosion from stainless steel is processed by macrophages locally and there is formed a mixture of hydrated ferric oxides similar to hemosiderin. This may be looked upon as a detoxication mechanism. There is evidence that in some specimens the limit of tissue tolerance for stored iron has been exceeded locally with consequent pathological changes.Another common deposit around stainless steel implants occurs in large plaques. It attracts giant cells and there is evidence that it is fibrotic and cytoto

ISSN:0021-9304    

DOI:10.1002/jbm.820080304

出版商:John Wiley&Sons, Inc.    

年代:1974

数据来源: WILEY

摘要:

AbstractSubstantial improvements have been made by the surgical manufacturing industry in the development of implants and by the orthopedic surgeon in the use of prosthetic appliances. In spite of these advancements, some prosthetic devices completely fail of do not provide satisfactory performance. Hostile environmental conditions of the human body are highly influential in limiting the service life of the implants, so the material selection and the design and fabrication must be made with extreme care. Examinations we have made of intramedullary pins retrieved from femurs reveal examples of fretting and/or crevice corrosion and in‐service failures that nucleated in microscopic surface gouges. Self‐tapping screws, essential for securing bone implants, failed due to fractures originating in the thread roots. Failures by merely exceeding the ultimate strength of the material and by the more involved process of stress corrosion cracking are shown.An evaluation laboratory for failure analyses of prostheses is recommen

ISSN:0021-9304    

DOI:10.1002/jbm.820080305

出版商:John Wiley&Sons, Inc.    

年代:1974

数据来源: WILEY

摘要:

AbstractTwo types of dense Al2O3ceramics (99.6% purity, 96% purity) were tested in the following fields of interest.1Wear resistibility using a pin and disk method under distilled water and human synovial fluid. Both types showed minimal initial corpuscular wear.2Biocompatibility of ceramic wear particles in mice and rats after injection by different ways. The crystal material is permanently deposited in macrophages, after transport via lymphpatic and blood vessels also in the RES without chronic inflammatory and progressive fibrotic response.3Under moderate stress conditions ceramic plates are fixed firmly by new bone formation within 2–3 months according to tetracycline label studies of bone growth in rats.4A new ceramic total hip prosthesis with two different socket designs for cement free fixation in bone is proposed and used in sheep experiments. The results of a 4 month experiment is presented showing firm fixation of the prosthesis under full stress condition

ISSN:0021-9304    

DOI:10.1002/jbm.820080306

出版商:John Wiley&Sons, Inc.    

年代:1974

数据来源: WILEY

摘要:

AbstractA series of nonporous glasses and glass materials designed with controlled surface ion activities to allow chemical bonding to bone are described. Surface reactivities of these materials in vitro are correlated with biological activities in vivo and in tissue culture. Direct chemical bonding of the materials to bone is demonstrated. The mechanism for development of this bond is through the production of an amorphous ion surface gel on the bioglass. This gel induces osteogenesis by a chemotactic response of osteoblasts.

ISSN:0021-9304    

DOI:10.1002/jbm.820080307

出版商:John Wiley&Sons, Inc.    

年代:1974

数据来源: WILEY

摘要:

AbstractA comprehensive protocol is presented for the in vivo evaluation of soft tissue foreign body reactions to surgical implants. A number of methods of evaluation and quantitation of the tissue reaction to implants are presented and discussed. A strong plea is made for semi‐quantitation of tissue reactions, rather than relying on subjective, qualitative method

ISSN:0021-9304    

DOI:10.1002/jbm.820080308

出版商:John Wiley&Sons, Inc.    

年代:1974

数据来源: WILEY

摘要:

AbstractThe adsorption, conformational changes, and desorption of biological molecules at foreign interfaces are effected by both kinetic and thermodynamic factors. The thermodynamic factors which drive the biomolecule/foreign interface system towards equilibrium include the enthalpy and entropy changes occurring during each step in the adsorption process. The principles governing interaction of proteins with nonwettable (nonpolar) and wettable (polar) foreign interfaces are discussed in terms of these thermodynamic parameters. Some examples to illustrate these arguments are presented are presented for plasma‐protein interactions on Silastic and radiation‐grafted hydrogel/Silastic interfa

ISSN:0021-9304    

DOI:10.1002/jbm.820080309

出版商:John Wiley&Sons, Inc.    

年代:1974

数据来源: WILEY

摘要:

AbstractA study of the tissue compatibility of aluminum oxide implants under different stress conditions in rabbits was performed over four‐ and eight‐week implantation periods. The specific objectives were to examine endosteal bone ingrowth into aluminum oxide coneshaped plugs in amputated tibiae, while additional pellet‐shaped implants in the tibiae and femora of rabbits with amputated and nonamputated limbs were studied to determine: (1) if the degree of loading placed on the amputated limb was sufficient to promote bone activity, (2) the degree of inertness and/or toxicity of the aluminum oxide implants, and (3) a possible cause of bone spurs.The results of the radiographic, histologic and microradiographic analyses of the in vivo implants demonstrated that there was little mineralized bone ingrowth into the coneshaped aluminum oxide implants in the amputated tibiae. The study also showed that the aluminum oxide pellet implants in the tibiae and femora of the nonamputated limbs demonstrated excellent mineralized bone ingrowth into surface and internal pores. By comparing these results with the incomplete ingrowth into corresponding pellet implants in the tibiae and femora of amputated limbs, it was determined that a lack of weight bearing and damage to the musculature and vascularity following amputation were interfering with the normal bone activity and therefore bone ingrowth.Angiographs and radiographs of the amputated tibiae demonstrated that bone spurs were present and that they originated at the site of the periosteal damage. Their cause was believed to be associated with an increase in the vascularity of the adjacent ti

ISSN:0021-9304    

DOI:10.1002/jbm.820080310

出版商:John Wiley&Sons, Inc.    

年代:1974

数据来源: WILEY

摘要:

AbstractOne method of providing an artificial limb for an amputee might be to attach the external prosthesis directly to the skeleton but a major problem is the behavior of the tissues at the point where the prosthesis penetrates the skin surface. Preliminary experiments have been carried out using small flexible implants in porcine skin to study the principles involved. It is confirmed that the epidermis grows down into the dermis around the nonporous materials and the implant‐skin junction is unstable and readily becomes infected. It was found that polytetrafluorethylene with pores of 10 μm diameter and hydron sponge with pores of 40 μm diameter became invaded by fibrous tissue and this appeared to prevent the migration of epidermis alongside the implants and a stable ring of epidermal tissue was formed near the skin surface. A review of other situations where epidermal migration is taking place suggests that epidermis is able to migrate through damaged collagenous tissue, possibly with the help of leucocytic enzymes, but that epidermal cell movement is halted when the epidermal sheet is confronted by heathly collagen bund

ISSN:0021-9304    

DOI:10.1002/jbm.820080311

出版商:John Wiley&Sons, Inc.    

年代:1974

数据来源: WILEY

摘要:

AbstractA standardized readily reproducible experimental model has been developed to assess the relative importance of the chemical and physical configuration of sutures as determinants of early infection in contaminated wounds. The chemical structure of the suture appeared to be the most important factor in the development of surgical infection. The incidence of infection in contaminated tissues containing either polypropylene sutures or nylon sutures was lower than the infection rate of tissues subjected to any other nonabsorbable suture. Among the absorbable sutures, polyglycolic acid (PGA) sutures evoked the least inflammatory response. The infection rate of contaminated tissues containing the PGA sutures was not significantly different from the incidence of infection of tissues subjected to the least reactive nonabsorbable sutures. The physical configuration of the suture played a relatively unimportant role in the development of early infection. The infection rate of contaminated tissues containing monofilament nonabsorbable sutures did not differ significantly from the incidence of infection of tissues subjected to multifilament sutures made from the same material. Coating the multifilament suture with either silicone, wax, or Teflon did not alter the incidence of early infection in the contaminated tissue. Finally, the presence of even the least reactive suture in contaminated subdermal tissue potentiated the development of infection.

ISSN:0021-9304    

DOI:10.1002/jbm.820080312

出版商:John Wiley&Sons, Inc.    

年代:1974

数据来源: WILEY