STP1560

    Denatured Protein Deposits Identified on Simulator and Explant Hip Bearings

    Published: May 2013


      Format Pages Price  
    PDF (2.8M) 13 $25   ADD TO CART
    Complete Source PDF (98M) 13 $100   ADD TO CART


    Abstract

    Simulator and explant studies have noted contamination of protein films on hip bearings. These films have been suggested to play a role in lubrication and wear mechanisms as both (i) a tribolayer and (ii) a confounding contaminant. It has been suggested that these films composed of protein might be responsible for cyclic weight fluctuations (0.2 to 2 mg) that can obscure gravimetric wear measurements. The aim of this work was to study protein films on simulator and explant hip bearings and develop a method for removing these protein films. Four types of bearings from simulators and explants (metal-on-metal [M-M], ceramic-on-ceramic [C-C], metal-on-polyethylene [M-PE], and ceramic-on-polyethylene [C-PE]) were examined for protein films. The topographies of protein films were characterized via interferometry and scanning electron microscopy. C-C bearings were washed with both acid and chemical solutions and M-M bearings were washed only with chemical solution and the topographies were analyzed. All bearing types were contaminated with protein films. The films were characterized as a thin adsorbed monolayer and clustered gelatinous “islands” predominantly located along the edge of the main wear zone. They were confirmed by their characteristic roughness and third-body wear tracks transitioning through the raised islands. Acid wash treatment on ceramics revealed a weight loss of up to 2 mg, whereas the chemical wash treatment yielded a weight loss that was 10 times less. The chemical wash successfully removed 1.8 mg of protein from the M-M simulator bearings. The accumulation of protein varied, with M-M and C-C ≫ M-PE and C-PE. The protein film topography on explanted bearings confirmed that protein films occur in vivo. The weight loss achieved through the wash treatments confirmed the removal of protein layers.

    Keywords:

    hip arthroplasty, lubrication, protein, simulator, explant


    Author Information:

    Burgett, M.
    Donaldson Arthritis Research Foundation, Colton, CA

    Donaldson, T.
    Donaldson Arthritis Research Foundation, Colton, CA

    Clarke, I. C.
    Donaldson Arthritis Research Foundation, Colton, CA

    Savisaar, C.
    CDRH/FDA, Silver Spring, MD

    Bowsher, J.
    CDRH/FDA, Silver Spring, MD


    Paper ID: STP156020120047

    Committee/Subcommittee: F04.22

    DOI: 10.1520/STP156020120047


    CrossRef ASTM International is a member of CrossRef.