Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 14 (1980), S. 567-586 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Repair or replacement of the damaged anterior cruciate ligament (ACL) is a significant clinical problem. A design utilizing ultrahigh-molecular-weight polyethylene (UHMWPE) was developed and marketed by an orthopaedic device manufacturer. Mechanical failure rates of greater than 10%/year postoperatively raised the issue of the adequacy of UHMWPE in that design. A study has been made to estimate the forces in the human anterior cruciate ligament for young, middle age, and older patients and to thus derive the minimum materials requirements for a now withdrawn prosthetic anterior cruciate ligament (PACL) design. It is concluded that UHMWPE does not possess adequate yield, creep, or fatigue properties to meet the design. Furthermore, consideration of the varying requirements on the PACL, due to differences in age and activity levels of patients, suggest that a band-type design offers a better possibility of achieving adequate materials performance in the ACL prosthetic replacement.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The release of corrosion products by implants has become a matter of concern. Using a microsphere model, the release of chromium, cobalt, and nickel, secondary to implantation of various surface area exposures of F-75, a cast cobalt-chromium alloy, was studied over a 30 day period in the rat. Dose related elevations were observed in the serum concentration of chromium and cobalt but not of nickel, with the maxima being achieved at 3 days after metal implantation followed by declines in concentration. The chromium elevation, approximately twelvefold for a surface area to body weight (SA/BW) ratio of 300 x is similar to that previously reported in patients receiving total hip replacement arthoplasties. However, the cobalt elevation, twentyfold for a SA/BW ratio of 300 x, has not been previously observed. These serum concentration changes are as yet unexplained, but are probably not due to fibrous capsule maturation or alloy repassivation.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 18 (1984), S. 99-114 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: An investigation into blood-borne organometallic compounds that arise from the corrosion of metals used in orthopedic prosthetic devices was conducted using an in vivo rat model with an implantation time of 10 days and an in vitro human serum model with an incubation time of 5 days. Both models involved 316LSS and HS-21Haynes Stellite 21: Stellite Division of Cobalt Corporation, Kokomo, Indiana (An alloy of very similar composition to ASTM F-75) in the spherical powder form of 55 ± 5 μm microns in diameter at three different surface areas to body weight ratios. Gel chromatography on cross-linked dextran (G-200) was used to fractionate the serum proteins which bound the metal ions (chromium, cobalt, and nickel) released and identify them. Atomic-absorption-spectrophotometry analysis measured the concentration of the metal ions in each serum protein peak as well as whole serum from both models, and red cell and tissue from the in vivo model. Within the serum proteins, the metal ions were bound to two of the principal serum protein peaks. Similar distributions of the metals among the serum protein peaks were not noted.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 26 (1992), S. 593-606 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Fiber reinforced polymer (FRP) composites are being developed as alternatives to metals for structural orthopedic implant applications. FRP composite fracture behavior and environmental interactions are distinctly different from those which occur in metals. These differences must be accounted for in the design and evaluation of implant performance. Fiber/ matrix interfacial bond strength in a FRP composite is known to strongly influence fracture behavior. The interfacial bond strength of four candidate fiber/matrix combinations (carbon fiber/polycarbonate, carbon fiber/polysulfone, polyaramid fiber/polycarbonate, polyaramid fiber/ polysulfone) were investigated at 37°C in dry and in vivo simulated (saline, exudate) environments. Ultimate bond strength was measured by a single fiber-microdroplet pull-out test. Dry bond strengths were significantly decreased following exposure to either saline or exudate with bond strength loss being approximately equal in both the saline and exudate. Bond strength loss is attributed to the diffusion of water and/or salt ions into the sample and their interaction with interfacial bonding. Because bond degradation is dependent upon diffusion, diffusional equilibrium must be obtained in composite test samples before the full effect of the test environment upon composite mechanical behavior can be determined.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 27 (1993), S. 1281-1291 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Fiber/matrix interfacial bonding in fiber reinforced polymer (FRP) composite materials is potentially sensitive to degradation in aqueous environments. Ultimate bond strength (UBS) in carbon fiber/polysulfone (CF/PSF) and polyaramid/polysulfone (K49/PSF) was previously reported to be significantly decreased in two simulated in vivo environments. While UBS is a useful parameter, for orthopedic implant applications the fatigue behavior of the interface is probably a more relevant indicator of long-term composite material performance. In this article, the effects of simulated in vivo environments (saline, exudate) upon the fatigue behavior of the interface of CF/PSF and K49/PSF are reported. The fatigue behavior of both material combinations was linearly dependent on the logarithm of fatigue life in the dry (control), saline, and exudate environments. Testing either material in saline and exudate resulted in significantly lower fatigue strength than in the dry environment; however, results in the two wet environments were indistinguishable. The CF/PSF interface experienced fatigue failure at approximately 105 load cycles at a maximum applied load level of only 15% of its ultimate dry bond strength without indication of a endurance limit being reached. These results raise some important questions regarding the durability of CF/PSF composite in load bearing orthopedic applications. © 1993 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 29 (1995), S. 1101-1110 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The biosynthetic and migratory response of bone cells to changes in both surface composition and morphology of polystyrene (PS) substrates was examined. A system was devised wherein micromachined silicon wafers were used as templates to solvent-cast PS replicas [using 0, 1, or 2 wt % styrene (S) monomer additions] with either 0.5- or 5.0- μm-deep surface grooves. Smooth replicas (0% S) served as the control surfaces. The chemical and morphologic characteristics of the nine unique model biomaterial surfaces (MBSs) produced using this system were documented and were found to be distinct. For the biosynthetic studies, bone cells isolated from neonatal rat calvaria were plated onto the MBSs and labeled at postconfluence with [14C]proline for 24 h. Total DNA per surface, total newly synthesized collagenous (CP), and noncollagenous protein (NCP) (cell associated and secreted) were determined. Cell-associated CP was found to increase significantly for the bone cells cultured on the substrates with 0.5-μm grooves and 2% S (P 〈 .05). Cell-associated NCP was found to be elevated for all 2% S substrates and for the 0.5-μm grooves substrates with 1% S. For the migration studies, bone cells were plated first onto 5-mm nitrocellulose disks that were attached to standard Petri dishes using a plasma clot. At confluence, the disks were removed aseptically and placed on the replicas. The cellular area occupied as a result of the outward migration of the bone cells was measured after 4 days of culture using an image analysis system. An average velocity for the leading edge of bone cell populations on each of the nine MBSs was calculated: Cells on surfaces with either 1% S or 5.0-μm grooves displayed significantly higher velocities than did the control cultures. A significant interaction effect between chemistry and morphology was observed. The biosynthetic and migratory responses of in vitro cultures of bone cells were not predictable from the observations of the cellular responses to the individual features, but appeared to depend on cellular responses to more than one substrate factor. © 1995 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 32 (1996), S. 447-457 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The surface characteristics of sixteen “monobloc” titanium-6% aluminum-4% vanadium (Ti6Al4V) femoral components (two of the 6-Ti-28 type and 14 of the 6-Ti-32 type) retrieved after periods of 78-131 months following loosening of the femoral component, as well as two unimplanted controls, were studied. The femoral heads were examined by a combination of noncontact light profilometry, scanning electron microscopy, and energy-dispersive X-ray analysis. No consistent correlations were found between classical surface roughness parameters (average, root mean square, peak-to-valley roughness, and radius of curvature) and any clinical parameter studied (patient gender, weight, and height; primary diagnosis; implantation time; or calculated force applied on the hip joint). This extensive quantitative topographic analysis suggests that wear mechanisms in vivo are complex and that wear of titanium alloy femoral heads is partly attributed to a combination of an imperfect nature of the surface before implantation, removal of the oxide layer causing abrasion of the alloy, subsequent deformation of the bearing surface including polishing, and, to a very small degree, patient parameters. © 1996 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 17 (1983), S. 655-668 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: An in vivo study of a new total finger joint prosthesis was performed to evaluate a biological ingrowth system of attachment of the device to bone. The prosthesis consisted of two conical ribbed ultrahigh molecular weight polyethylene plugs that were fixed by impaction into the medullary cavity after reaming. A cobalt-chromium alloy metal stemmed hinge slides inside the plugs with the joint articulation at the end of the stem. The focus of this study was to measure the concentration of cobalt and nickel in the serum, erythrocytes, and periarticular tissue (muscle from the sartorius and vastus medialis) resulting from the implantation of this device in the knee of the cat for periods of up to 1 year. The results indicate significant elevation in serum cobalt concentrations only after 5 months and increased concentrations in serum nickel which, were more pronounced after two months. Column chromatographic separations on cross-linked Dextran (G-200) shows a different distribution across the three principal protein peaks for each metal.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: There is concern whether in vivo corrosion of chromium-cobalt alloys releases ions containing trivalent [Cr(III)] or hexavalent [Cr(VI)] chromium. The question arises from indications that Cr(VI) is far more biologically active than Cr(III). Using a previously developed microsphere implant model, specimens of F-75 chromium-cobalt-molybdenum alloy were implanted in rats for periods up to 120 days. Blood and urine were collected at intervals during the study. Significant postoperative serum and urine chromium concentration elevations were observed. In addition, weight gain inhibition, lung morbidity, and animal mortality, related to the implant surface area to animal body weight ratio (SA/BW), were observed. Comparison of measured chromium serum concentrations with those concentrations found by others to be biologically active in tissue culture studies strongly suggests the release of Cr(VI) in this study.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 21 (1987), S. 1213-1230 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A pyrolytic carbon coating was applied to F-75 chromium-cobalt-molybdenum alloy in an effort to reduce the release of corrosion products in vivo. After intramuscular implantation in the rat, a complex pattern of serum and urine concentration elevations of chromium, cobalt, and nickel was seen. The carbon-coated implants released more chromium and cobalt than uncoated controls, as seen by significantly elevated metal concentrations in serum and urine. Animals receiving carbon-coated implants showed a high rate of recurrent implant site inflammation. Neoplastic infiltration of the implant site occurred in 3 out of 24 animals with coated implants, but not in any of the 16 animals which received either uncoated F-75 microsphere or poly(ethylene) particulate implants.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...