Synthetic periprosthetic synovial fluid development for in vitro cell‐tribocorrosion testing using the Taguchi array approach

Abstract

Synovial fluid is dynamic in vivo with biological components changing in ratio and size depending on the health of the joint space, making it difficult to model in vitro. Previous efforts to develop synthetic synovial fluid have typically focused on single organic‐tribological interactions with implant surfaces, thus ignoring interplay between multiple solution components. Using a Taguchi orthogonal array, we were able to isolate the individual effects of five independent synovial fluid composition variables: ratios of (1) hyaluronic acid to phospholipids (HA:PL) and (2) albumin to globulin (A:G), and concentrations of (3) hydrogen peroxide (H2O2), (4) cobalt (Co2+) and (5) chromium (Cr3+) ions on macrophage viability and reduced glutathione production, local solution pH and the comprehensive CoCrMo alloy electrochemical response. While no single synovial fluid variable significantly affected the collective response, HA:PL ratio resulted in the largest impact factor (Δ) on 12 of the 13 measured responses with significant effects (p < .05) on the average macrophage survival rate and electrochemical capacitive state of the CoCrMo surface. Cluster analysis separated significant responses from all trials into three groups, corresponding to healthy, mild, or severely inflamed fluids, respectively; with the healthy synovial fluid composition having mid‐range HA:PL ratios with no Co2+ ions, and the severely inflamed fluids consisting of low and high HA:PL ratios with H2O2 and Co2+ ions. By utilizing the Taguchi approach in combination with cluster analysis, we were able to advance our knowledge of complex multivariate synthetic synovial fluids influence on macrophage and electrochemical behavior at the cell‐solution‐metal interface.

Oxide degradation precedes additively manufactured Ti‐6Al‐4V selective dissolution: An unsupervised machine learning correlation of impedance and dissolution compared to Ti‐29Nb‐21Zr

“…28,33,34,[68][69][70] To reproduce the electrolyte solution in vivo, others have used synovial fluid, and Taguchi approaches. [71][72][73] A truly representative in vivo solution may require elements of all these approaches. In this study, we used 0.1 M H 2 O 2 -PBS, a much higher concentration than the 10 À4 M documented in vivo.…”

“…Various researchers have added hydrochloric acid to H 2 O 2 containing solutions (decreasing pH), cultured and activated macrophages, and investigated the synergistic effect of commonly adhering proteins at the device interface 28,33,34,68–70 . To reproduce the electrolyte solution in vivo, others have used synovial fluid, and Taguchi approaches 71–73 . A truly representative in vivo solution may require elements of all these approaches.…”

CORR Insights®: Are Damage Modes Related to Microstructure and Material Loss in Severely Damaged CoCrMo Femoral Heads?

“…Collaborations between clinicians, biologists, and corrosion experts are needed to design human joint fluid electrochemical tests to recapitulate the observed in vivo corrosion processes. Future studies should also develop simulated inflammatory joint fluid conditions [11]. Researchers can then test the corrosion characteristics of both CoCrMo and Ti-6Al-4V.…”