Role of corrosion in taper failure and head disassociation in total hip arthroplasty of a single design

Abstract

Modular junctions have been associated with corrosion in total hip arthroplasty. In a small number of cases, disassociation of the femoral head from the stem following gross wear of the taper has been reported. The purpose of this study was to investigate the role of corrosion in the development of mechanical changes leading to disassociation. Twenty-one retrieved stems and heads of one design previously reported with head disassociation were identified in an IRB-approved database. Components were scored for corrosion and measured for material loss. Stem alloy hardness was measured. Parametric and non-parametric statistics were performed (α < 0.05). Seven of twenty-one stems demonstrated gross material loss of the stem taper and head disassociation. The maximum linear depth (MLD) of material loss on stem tapers without dissociation and all head bores was 7.63 ± 6.04 and 63.76 ± 60.83 μm, respectively. Hardness of the stem material was statistically distinct, but similar to other stem materials. Results suggest material loss via corrosion at the head bore loosens the taper lock, allowing relative motion leading to abrasive wear of the stem taper. All cases of disassociation occurred at greater than 65 months with a minimum of 50 μm of loss at on the head bore. It may be warranted to survey patients with systems reporting head disassociation; for this system, including recalled heads, risk appears to begin after 6 years in vivo. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

Gross trunnion failure after a metal-on-polyethylene total hip arthroplasty leading to dissociation at the femoral head-trunnion interface

“…All components were successfully fixed. Based on retrieval evaluation of similar failures [6] , [7] we believe this failure occurred as a result of unrecognized MACC leading to subsequent GTF, and polyethylene liner failure. With the support of current literature, we hypothesize that this patient’s THA failed because he has several risk factors that have been associated with MACC and GTF.…”

“…This case report demonstrates GTF with malformation of the trunnion leading to dissociation at the head-trunnion interface. We hypothesize that this was secondary to MACC based on the time to failure, prior proposals of the mechanism of GTF [6] , [7] and the fact that this type of implant (a titanium alloy trabecular metal stem with 12/14 trunnion) has previously been described to have MACC in the time frame implanted [9] . In a case series of 5 patients who presented with GTF after non–metal-on-metal THA bearings, Banerjee et al.…”

“…His right lower extremity was 3.5 cm shorter than his left. The anteroposterior and lateral radiographs of the affected hip demonstrated what appears to be a GTF [3] , [6] , [7] ( Fig. 3 ).…”

“…MACC at the femoral head-trunnion interface eventually increases susceptibility to adverse local tissue reaction which is a local hypersensitivity response to Co fretting and corrosion products from MACC [5] . Long-standing MACC causes material loss at the taper junction which in rare cases may lead to gross trunnion failure (GTF) with frank taper disassociation and issues such as marked trunnion deformity, fracture, with or without dislocation at the femoral head-trunnion interface [3] , [5] , [6] , [7] .…”

Standardizing terms for tribocorrosion-associated adverse local tissue reaction in total hip arthroplasty

“…Some retrieved tapers show evidence of etching and grain egression (a mechanism of fatigue-crack initiation) at these interfaces, suggesting macroscopic movement [24]. Furthermore, corrosion at the interface may lead to instability and macromotion, making them further susceptible to abrasive wear [17,24,25], although this may be prosthesis specific [16].…”