Long-term biostability of polyacetal (Delrin) implants.
Over the past two decades, polyacetal homopolymer (Delrin) has been used for heart valve occluders and in total hip replacements. Both types of implants are subject to mechanical loads that induce wear, and excessive wear could adversely affect the performance of the device. The present study examined components of Delrin heart valves and hip prostheses that had been recovered from patients after extended periods of use in vivo. The molecular properties of these were compared to non-implanted control components, manufactured during approximately the same time period, including comparison between mechanically loaded and non-loaded regions of the implants. The results of infrared spectroscopy, dilute solution viscosity and gel permeation chromatography provided no evidence of systematic degradation of the Delrin components due to long term exposure to biological fluids and cyclic loading, which would indicate the potential for a late decrease in resistance to wear.
McKellop
H A
HA
J. Vernon Luck Orthopaedic Research Center, Orthopaedic Hospital, Los Angeles, CA 90007, USA.
Milligan
H L
HL
Röstlund
T
T
D001672:Biocompatible Materials; D002850:Chromatography, Gel / Q000379:methods; D006350:Heart Valve Prosthesis; D006351:Heart Valves; D006622:Hip Prosthesis; D006801:Humans; D066298:In Vitro Techniques; D012117:Resins, Synthetic / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D014783:Viscosity
D001672:Biocompatible Materials; D012117:Resins, Synthetic; C010102:delrin