Biocompatibility testing of simulated total joint arthoplasty articulation debris

Abstract

Surface characterization was performed to evaluate the surface condition of an uncoated cobalt alloy disc (control), and discs with medium and thick boron coatings for total joint articulating surfaces. Discs were characterized by scanning electron microscopy before and after dissolution studies. Chemical analyses of elemental transfer to the solution were assessed to evaluate the surface stability of the new coating. An in vivo biocompatibility study for particulates [of boron (B), titanium alloy (Ti), cobalt alloy (Co), and combinations of B + Ti and B + Co] was performed using a rat air pouch model. The inflammatory reactions to particulates were evaluated histologically and histochemically. No physical alteration was seen in the discs after the dissolution studies, and the elemental transfer to the dissolution solution was minimal. The cytokines, tumor necrosis factor (TNFalpha), and histology results from these simulated debris showed similar and moderate level responses magnitudes for the boron and mixtures and the primary alloy particulates. The conclusion from this initial study was that assessments of the coated discs showed physical properties similar to control. Also results from the in vivo studies of simulated wear debris from boron coatings on titanium and cobalt alloys demonstrated biocompatibility profiles that were mild to moderate and similar to prior analyses of wear debris products in synovial pouch models.

Tribo-mechanical properties of thin boron coatings deposited on polished cobalt alloy surfaces for orthopedic applications

“…Moreover, ion release from boron, when it occurs, is expected to be in the form of boric acid, which is a mild antiseptic, commonly used in ophthalmic solutions. The results of a recent, standardized biocompatibility study of boron, and boron-coated Co-Cr-Mo are consistent with these expectations, and will be reported separately from this paper [16].…”

Biological Reactions to Metal Particles and Ions in the Synovial Layer of Mice

“…In contrast to various in vitro cell culture studies that focus on one cell type [32,40], the murine model can not only reflect complex cellular and tissue interactions, but can also mimic the dynamic process of joints. Additionally, compared with other models, such as hamsters' skinfold-chamber models [41] and "air pouch" models [42], results from this model, as the suspensions were injected intraarticularly, are easier to translate into a clinical scenario because the generated wear debris primarily accumulates in the joint that has been replaced. In terms of the characteristics of metal materials, the CoCrMo particles and ions used in our study were consistent with those found in some clinical studies.…”

Local Biological Reactions and Pseudotumor-Like Tissue Formation in relation to Metal Wear in a Murine In Vivo Model

“…A common accepted theory of metal wear debris is that it is capable of stimulating the formation of aseptic lymphocytic vasculitis lesions around the prosthesis, which is characterized by diffusing lymphocytic infiltrates and extensive connective tissue necrosis [46]. Various other animal models that have attempted to study aseptic implant loosening, such as hamsters' skinfold-chamber models [46] and “air pouch” models [47], have yielded to date unreliable and limiting information that is not translatable into the clinical scenario, as the particle stimulation site does not correlate with the situation after surgery: the generated wear debris primarily accumulates in the joint that had been replaced. Different from other studies, this study uses an animal model to compare the biological inflammatory response of CoCr particles and CoCr ions in the knee joint in vivo .…”