Third-body wear is believed to be one trigger for adverse results
with metal-on-metal (MOM) bearings. Impingement and subluxation
may release metal particles from MOM replacements. We therefore
challenged MOM bearings with relevant debris types of cobalt–chrome
alloy (CoCr), titanium alloy (Ti6Al4V) and polymethylmethacrylate
bone cement (PMMA). Cement flakes (PMMA), CoCr and Ti6Al4V particles (size range
5 µm to 400 µm) were run in a MOM wear simulation. Debris allotments
(5 mg) were inserted at ten intervals during the five million cycle
(5 Mc) test. Objectives
Methods
To quantify and compare peri-acetabular bone mineral density
(BMD) between a monoblock acetabular component using a metal-on-metal
(MoM) bearing and a modular titanium shell with a polyethylene (PE)
insert. The secondary outcome was to measure patient-reported clinical
function. A total of 50 patients (25 per group) were randomised to MoM
or metal-on-polyethlene (MoP). There were 27 women (11 MoM) and
23 men (14 MoM) with a mean age of 61.6 years (47.7 to 73.2). Measurements
of peri-prosthetic acetabular and contralateral hip (covariate)
BMD were performed at baseline and at one and two years’ follow-up.
The Western Ontario and McMaster Universities osteoarthritis index
(WOMAC), University of California, Los Angeles (UCLA) activity score,
Harris hip score, and RAND-36 were also completed at these intervals.Objectives
Methods
