Investigations on the galvanic corrosion of multialloy total hip prostheses

Abstract

Total hip prostheses combining cobalt and titanium alloys in direct physical contact are currently being used. The purpose of this paper was to investigate the possibility of an accelerated corrosion occurring due to the coupling of these alloys. Electrochemical corrosion studies based on mixed potential and protection potential theories were used to study the in vitro effects of coupling the titanium and cobalt alloys. Verification of these studies was made by direct coupling experiments. Macroscopic examination of' surface features of four retrieved total hip prostheses ranging from 0-6 years implantation were conducted. The electrochemical studies predicted coupled corrosion potentials of -0.22 V and low coupled corrosion rates of 0.02 microA/cm2. Direct coupling experiments verified these results. Cobalt-titanium interfaces on the implants were macroscopically examined, and no instances of extensive corrosion were found. Overall, the in vitro corrosion studies and the examination of retrieved prostheses predicted no exaggerated in vivo corrosion due to the coupling of these cobalt and titanium alloys.

Adverse Local Tissue Reaction Associated With a Modular Hip Hemiarthroplasty

“…This combination increases the risk of galvanic corrosion; however, the reported coupled corrosion potentials generated are low with small observed corrosion rates in an in vitro direct coupling study [12]. The stem used in the primary surgery in this case was reported in a case of adverse reaction to metal debris in a metal-on-polyethylene THA [11].…”

Modern Trunnions Are More Flexible: A Mechanical Analysis of THA Taper Designs

“…Corrosion at this modular junction was first described in the early 1980s [30] and has since been well documented in numerous retrieval analyses [10,12,13,18,28]. The underlying etiology for corrosion at this interface is multifactorial, but one of the strongest predictors of corrosion found at retrieval was the flexural rigidity of the femoral trunnion [23].…”

“…Should revision arthroplasty be required, it also allows for easier surgical exposure and more potential options [8,14]. Shortly after the introduction of modularity in THA, issues of fretting and corrosion at the modular head-neck junction were identified [30], and have since been well documented [10,12,13,18,28]. Early retrieval analyses of femoral components attempted to identify the cause of corrosion, and although initially thought to be galvanic [7], an increasing body of literature points toward a mechanical etiology secondary to fretting and crevice-associated mechanisms of corrosion at the head-neck junction [4,22].…”

Corrosion at the Head-Neck Taper as a Cause for Adverse Local Tissue Reactions After Total Hip Arthroplasty

“…T he idea that corrosion might occur at the head-neck taper of the femoral component of a total hip prosthesis was first described in the early 1980s 30 , and the concept that modular tapers are susceptible to mechanically assisted crevice corrosion, a combination of fretting and crevice corrosion, was subsequently introduced 6 . Since that time, there have been numerous reports of corrosion at this taper interface, documented primarily in retrieval studies [2][3][4][5]8,[13][14][15][16][17][18] or, in rare cases, in association with catastrophic failure 2,7 .…”