99.
Revision Risk of Total Hip Arthroplasty with Ceramic-on-Ceramic
Bearings
Claus Varnum, Alma B. Pedersen, Per Kjærsgaard-Andersen, Søren
Overgaard
Dept. of Orthopaedic Surgery Vejle Hospital; Dept. of Clinical Epidemiology,
Aarhus University Hospital; Dept. of Orthopaedic Surgery, Vejle Hospital;
Dept. of Orthopaedic Surgery and Traumatology, Odense University Hospital
Background:
In general, the prognosis after total hip arthroplasty (THA) is
good with a 10 year overall survival rate around 90% in national registry
studies.
Purpose / Aim of Study:
We wanted to investigate revision risk of ceramic-
on-ceramic (CoC) THA after a maximum of 8.7 years follow-up.
Materials and Methods:
From Danish Hip Arthroplasty Registry 47,155
primary THAs operated from 2002 to 2009 were included into the study. Since
2,384
THAs were registered with a missing value for type of bearings,
multiple imputation was used. Cox regression analysis was performed to
estimate the relative risk (RR) of any revision with 95% confidence intervals
(
CI)
Findings / Results:
The RR for any revision was 0.97 (95% CI, 0.76-1.24) for
CoC THA, 0.84 (95% CI, 0.72-0.97) for ceramic-on- polyethylene (CoP)
THA, and 0.99 (95% CI, 0.68-1.44) for metal-on-metal (MoM) THA
compared to metal-on-polyethylene (MoP) THA. Stratified analyses for
gender, age, comorbidity, osteoarthritis of the hip, head size, uncemented
THA, follow-up shorter or longer than 2 years, revision for aseptic loosening,
dislocation, and other revision causes, showed no difference in RR for revision
for CoC THA compared to MoP THA. For CoP compared to MoP bearings a
lower RR for any revision was found for females (RR 0.75, 95% CI 0.61-
0.92),
patients older than 60 years (RR 0.82, 95% CI 0.68-0.98), patients with
any comorbidity (RR 0.70, 95% CI 0.54-0.89), and patients with 28 mm or
smaller heads (RR 0.84, 95% CI 0.70-0.99). For MoM THA the RR of revision
due to aseptic loosening was higher compared to MoP THA (RR 2.33, 95%
CI: 1.14-4.76).
Conclusions:
We found no difference in RR for any revision of CoC THA
compared to MoP THA. CoP THA had reduced risk for any revision in general
and among certain groups of patients and MoM THA had higher RR for
revision due to aseptic loosening compared to MoP THA.
