There are limited published data detailing the volumetric material loss from tapers of conventional metal-on-polyethylene (MoP) total hip arthroplasties (THAs). Our aim was to address this by comparing the taper wear rates measured in an explanted cohort of the widely used Exeter THA with those measured in a group of metal-on-metal (MoM) THAs. We examined an existing retrieval database to identify all Exeter V40 and Universal MoP THAs. Volumetric wear analysis of the taper surfaces was conducted using previously validated methodology. These values were compared with those obtained from a series of MoM THAs using non-parametric statistical methodology. A number of patient and device variables were accounted for using multiple regression modelling.Aims
Patients and Methods
We sought to determine whether cobalt-chromium alloy (CoCr) femoral
stem tapers (trunnions) wear more than titanium (Ti) alloy stem
tapers (trunnions) when used in a large diameter (LD) metal-on-metal
(MoM) hip arthroplasty system. We performed explant analysis using validated methodology to
determine the volumetric material loss at the taper surfaces of
explanted LD CoCr MoM hip arthroplasties used with either a Ti alloy
(n = 28) or CoCr femoral stem (n = 21). Only 12/14 taper constructs
with a rough male taper surface and a nominal included angle close
to 5.666° were included. Multiple regression modelling was undertaken
using taper angle, taper roughness, bearing diameter (horizontal
lever arm) as independent variables. Material loss was mapped using
a coordinate measuring machine, profilometry and scanning electron
microscopy.Aims
Patients and Methods
We wished to investigate the influence of metal debris exposure
on the subsequent immune response and resulting soft-tissue injury
following metal-on-metal (MoM) hip arthroplasty. Some reports have
suggested that debris generated from the head-neck taper junction
is more destructive than equivalent doses from metal bearing surfaces. We investigated the influence of the source and volume of metal
debris on chromium (Cr) and cobalt (Co) concentrations in corresponding
blood and hip synovial fluid samples and the observed agglomerated
particle sizes in excised tissues using multiple regression analysis
of prospectively collected data. A total of 199 explanted MoM hips
(177 patients; 132 hips female) were analysed to determine rates
of volumetric wear at the bearing surfaces and taper junctions. Aims
Patients and Methods
