Characterisation of the oxide film on the taper interface from retrieved large diameter metal on polymer modular total hip replacements

Abstract

a b s t r a c tMany metal joint failures have been associated with adverse local tissue reactions due to the response of the body to wear debris and corrosion products, released from the bearing surfaces or the taper interfaces. The oxide film on the CoCrMo plays an important role in the electrochemical behaviour, however, there is a lack of quantitative data on the structure and distribution of oxides following in vivo operation. In the present study, detailed analysis of the surface layer on the taper interfaces is provided. Two retrieved taper interfaces were analysed. Site-specific FIB/TEM cross-sections show evidence of the oxide film and the carbonaceous layer. High resolution TEM results show the oxide film has porous texture and EELS confirmed it is chromium oxide.

Subsurface characterisation of wear on mechanically polished and electro-polished biomedical grade CoCrMo

“…9) indicated C-K, Ca-L and N-K edges, but with no Cr, Co or Mo suggesting that no metal dissolution had occurred into the organic layer. The composition of the layer is similar in structure to an organic layer observed on the CoCrMo surface of a taper, explanted from a patient after 4 years in vivo [17]. However, the structure is different to the observations by other authors [20][21][22][23][24] who suggested the layer was organic material mixed with metal and oxide particles.…”

“…The surface structure of CoCrMo alloys has been the subject of much interest [11][12][13][14][15][16][17]. A number of surface specific structures have been observed in both in vivo and in vitro CoCrMo alloys, which include a nanocrystalline layer, usually at the outermost metal surface, the formation of ε-martensite, mechanical twinning and dislocation flow.…”

“…The presence of carbon and oxygen was seen in most of the surface layer, while some layers showed traces of sodium, magnesium, calcium, nitrogen, sulphur, phosphorus and chlorine. Zeng et al [17] analysed the organic layer on the taper interface from retrieved large diameter metal on polymer modular total hip replacement. An amorphous organic layer was observed in all regions of taper interface as the outermost layer, as thickness various from region to region.…”

Surface and subsurface changes as a result of tribocorrosion at the stem-neck interface of bi-modular prosthesis

“…It has been shown that HC CoCrMo alloys possess lower passive corrosion currents when in bulk like FCC form. Whilst a wealth of knowledge exists for sliding interfaces, in which the tribology has been refined over a number of years, only one study deals with the processes occurring at the nano-scale for modular taper surface [39] (either stem-neck or head-neck). This is surprising considering the breadth of research currently been conducted in this area.…”

Fretting–corrosion at the modular tapers interface: Inspection of standard ASTM F1875-98

“…It is reasonable to assume that the local interfacial metallurgy, chemistry and mechanical properties will be affected and as a result will impact on the evolution wear and corrosion. [23][24][25] While consideration of the male taper topography is an important variable in modular tapers design, the main driver behind the surface topography in modularity must not be forgotten, to facilitate the use of different head materials. Although topography is one aspect of consideration, it is obvious that the tapermachined surface is one variable in a fine balancing act contributing to the design of an optimum modular tapers.…”