Proximal Component Modularity in THA—At What Cost?: An Implant Retrieval Study

Abstract

Background While modular femoral heads have been used in THA for decades, a recent innovation is a second neck-stem taper junction. Clinical advantages include intraoperative adjustment of leg length, femoral anteversion, and easier revision, all providing flexibility to the surgeon; however, there have been reports of catastrophic fracture, cold welding, and corrosion and fretting of the modular junction.

Adverse Local Tissue Reaction Arising from Corrosion at the Femoral Neck-Body Junction in a Dual-Taper Stem with a Cobalt-Chromium Modular Neck

“…Numerous concerns have arisen in recent years over potential complications specific to dual-tapered stem designs, including the potential for fracture of the modular neck component [9][10][11][41][42][43][44][45] , dissociation of the modular neck from the body 46,47 , and corrosion at the modular neck-body interface [4][5][6][7][8] . However, to date, there have been only two small case series describing a total of five cases of adverse local An energy-dispersive x-ray spectrum (Case 5) reveals the elemental composition of particles rich in chromium (Cr) and consistent with chromium phosphate corrosion product.…”

“…While this may relate to a susceptibility of this specific stem design to corrosion, adverse local tissue reactions have also been reported in association with other dual-taper stem designs that feature a modular cobalt-chromiumalloy neck 5,21 . The material composition of the modular components may also influence their susceptibility to corrosion; it is less likely that a modular neck made from a titanium alloy (thereby allowing for a titanium-titanium modular junction) would lead to adverse local tissue reaction 5 as there is no potential source for cobalt or chromium release from such a junction 52 . However, these titanium modular necks have been associated with fracture [9][10][11][41][42][43][44][45] .…”

“…Although corrosion at this junction has been documented in retrieval analyses [4][5][6] , in vitro studies 7,8 , and case reports of modular neck fracture [9][10][11] , the biological implications of taper corrosion at this junction are poorly understood. Recent studies have documented the potential for taper corrosion at the head-neck junction to lead to the release of metal debris and severe adverse local tissue reactions [12][13][14][15][16] , such as that seen in patients with failed metal-on-metal bearings [17][18][19][20] .…”

“…T 15,2013 tissue reaction in response to corrosion at the modular neckbody junction; these occurred in different dual-taper stem designs that also utilized modular cobalt-chromium-alloy necks 5,21 . The current study documents the potential for this process to cause pain and severe soft-tissue destruction around the hip in a larger cohort of patients, which can lead to early failure within the first several years of implantation.…”

Properties and Corrosion Performance of Self-reinforced Composite PEEK for Proposed Use as a Modular Taper Gasket

“…Many efforts have been made to document in vivo evidence of fretting corrosion through retrieval studies aimed at a better understanding of the mechanisms through which it occurs and the conditions that may lead to its initiation [3,6,11,12,15,18,23,27]. Furthermore, in vitro models to understand the performance of tapers in a simulated physiologic situation have been developed, and there are multiple reports linking cyclic loading of headneck tapers to the generation of corrosion currents in these models [13,14,20].…”