Biomechanical and allergological characteristics of a biodegradable poly(D,L-lactic acid) coating for orthopaedic implants.
A poly(D,L-lactic acid) surface coating (PDLLA) has been developed to optimize interactions at the implant-tissue interface. Mechanical and allergological characteristics were evaluated in the present study to elucidate possible indications and limitations prior to clinical application. Implants of stainless steel and Ti-6Al-4V and Co-Cr-Mo alloys were coated with PDLLA, and mechanical stability was studied during intramedullary implantation into rat and human cadaver bones and during dilation of coronary artery stents. Elongation resistance was examined on AlMgSi alloy specimens. Furthermore, proliferation of peripheral blood mononuclear cells of nickel-allergic donors and controls and interleukin-4 and interferon-gamma levels were measured in the presence of coated/uncoated implants and after stimulation with phytohemagglutinin or NiSO4. PDLLA remained stable on the implants with a minimum of 96% of the original coating mass and tolerated lengthening of at least 8%. Further lengthening was followed by microcracking and cohesive failure within the coating. PDLLA exerted no suppressive effect upon spontaneous and pan-T-cell mitogen inducible T-cell proliferation. Furthermore, specific proliferation to nickel in cells of nickel-allergic blood donors and production of interleukin-4 and IFN-gamma were not influenced by the coating. PDLLA coating proved high mechanical stability on different orthopaedic implants and did not influence in vitro T-cell reactivity towards specific biomaterials.
Gollwitzer
Hans
H
Klinik und Poliklinik für Orthopädie und Sportorthopädie, Technische Universität München, Ismaninger Str. 22, 81675 München, Germany. h.gollwitzer@lrz.tu-muenchen.de
Thomas
Peter
P
Diehl
Peter
P
Steinhauser
Erwin
E
Summer
Burkard
B
Barnstorf
Sonja
S
Gerdesmeyer
Ludger
L
Mittelmeier
Wolfram
W
Stemberger
Axel
A
D000328:Adult; D000497:Alloys; D000818:Animals; D002102:Cadaver; D002455:Cell Division / Q000276:immunology; D002858:Chromium Alloys; D020099:Coated Materials, Biocompatible; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology*; D066298:In Vitro Techniques; D019344:Lactic Acid / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D009532:Nickel / Q000276:immunology; D011091:Polyesters; D011108:Polymers; D019736:Prostheses and Implants; D051381:Rats; D033081:Shear Strength; D013193:Stainless Steel; D013601:T-Lymphocytes / Q000276:immunology; D014025:Titanium / Q000276:immunology
D000497:Alloys; D002858:Chromium Alloys; D020099:Coated Materials, Biocompatible; D011091:Polyesters; D011108:Polymers; C103771:cobalt-chromium-molybdenum-carbon alloy; D013193:Stainless Steel; C031462:titanium alloy (TiAl6V4); D019344:Lactic Acid; C033616:poly(lactide); D009532:Nickel; D014025:Titanium