Corrosion of Metals During Use in Arthroplasty

Abstract

Arthroplasty implants can undergo corrosion at the modular components, trunnion, and hinges, owing to implant material makeup, micromotion, and interaction with body fluid. In this review, various mechanisms of corrosion in arthroplasty were explored with suggestions on means of improvement. We identified 10 methods including pitting, crevice, mechanically assisted crevice corrosion, fretting, fretting initiated crevice corrosion, mechanically assisted taper corrosion, galvanic corrosion, stress/ tension, fatigue corrosion, and inflammatory cell induced corrosion. The position of implants on the galvanic series, and their ability to maintain passivation contribute to their longevity in service. Due to the relative motion of arthroplastic components, bio-tribocorrosion may disrupt passive oxide films, and pitting is initiated at interfaces. Thus, corrosion in arthroplasty as an electrochemical phenomenon mainly starts on one spot and progresses in 3 steps: (1) the oxidative dissolution of metal from implant surfaces into the aqueous active environment, releasing cations, (2) the attraction of electrons to the opposite charge created at another point of the implant surface, producing current flow, and (3) the formation of oxides of metal and metal hydroxides deposited as rust at the surface of the implant. Recent innovations in material manufacturing continue to improve the efficiency of arthroplasty; however, the component parts remain susceptible to biotribocorrosion. Thus, a complete eradication of corrosion in arthroplasty would require futuristic materials with improvement in recent materials and designs, derived from knowledge of existing retrieved implants, and strategies to provide overall surface finishes that protect against bio-tribocorrosion.

A review on manufacturing processes of cobalt‐chromium alloy implants and its impact on corrosion resistance and biocompatibility

“…When the metals and alloys were started to find extensive applications in medical devices, between the early 1960s and late 1980s, numerous comparative studies were conducted to better understand the biological effects of metal ion extractables released into the body due to the corrosion of metallic implants 34–40 . The implants can undergo various forms of localized corrosion such as crevice, fretting, and galvanic corrosion depending on the implant type, material, shape, design, geometry, surface characteristics, mechanical function, load bearing capacity, material‐to‐material interface, and in‐vivo conditions at the implant site 41–43 . The corrosion products, depending on the type, form, size, and concentration, can adversely affect the implant biocompatibility 44–46 …”