Joint registries typically use revision of an implant as an endpoint and report survival rates after a defined number of years. However, reporting lifetime risk of revision may be more meaningful, especially in younger patients. We aimed to assess lifetime risk of revision for patients in defined age groups at the time of primary surgery. The New Zealand Joint Registry (NZJR) was used to obtain rates and causes of revision for all primary total hip arthroplasties (THAs) performed between January 1999 and December 2016. The NZJR is linked to the New Zealand Registry of Births, Deaths and Marriages to obtain complete and accurate data. Patients were stratified by age at primary surgery, and lifetime risk of revision calculated according to age, sex, and American Society of Anesthesiologists (ASA) classification. The most common causes for revision were also analyzed for each age group.Aims
Methods
The primary aim of this independent prospective randomised trial
was to compare serum metal ion levels for ceramic-on-metal (CoM)
and metal-on-metal (MoM) bearing surfaces in total hip arthroplasty
(THA). Our one-year results demonstrated elevation in metal ion
levels above baseline with no significant difference between the
CoM and MoM groups. This paper reviews the five-year data. The implants used in each patient differed only in respect to
the type of femoral head (ceramic or metal). At five-year follow-up
of the 83 enrolled patients, data from 67 (36 CoM, 31 MoM) was available
for comparison.Aims
Patients and Methods
We compared the rate of revision for instability
after total hip replacement (THR) when lipped and non-lipped acetabular
liners were used. We hypothesised that the use of a lipped liner
in a modular uncemented acetabular component reduces the risk of
revision for instability after primary THR. Using data from the
New Zealand Joint Registry, we found that the use of a lipped liner
was associated with a significantly decreased rate of revision for instability
and for all other indications. Adjusting for the size of the femoral
head, the surgical approach and the age and gender of the patient,
this difference remained strongly significant (p <
0.001). We conclude that evidence from the New Zealand registry suggests
that the use of lipped liners with modular uncemented acetabular
components is associated with a decreased rate of revision for instability
after primary THR. Cite this article:
In a double-blinded randomised controlled trial,
83 patients with primary osteoarthritis of the hip received either
a ceramic-on-metal (CoM) or metal-on-metal (MoM) total hip replacement
(THR). The implants differed only in the bearing surfaces used.
The serum levels of cobalt and chromium and functional outcome scores
were compared pre-operatively and at six and 12 months post-operatively. Data were available for 41 CoM and 36 MoM THRs (four patients
were lost to follow-up, two received incorrect implants). The baseline
characteristics of both cohorts were similar. Femoral head size
measured 36 mm in all but two patients who had 28 mm heads. The
mean serum cobalt and chromium levels increased in both groups,
with no difference noted between groups at six months (cobalt p
= 0.67, chromium p = 0.87) and 12 months (cobalt p = 0.76, chromium
p = 0.76) post-operatively. Similarly, the mean Oxford hip scores,
Western Ontario and McMaster Universities Osteoarthritis index and
University of California, Los Angeles activity scores showed comparable improvement
at 12 months. Our findings indicate that CoM and MoM couplings are associated
with an equivalent increase in serum cobalt and chromium levels,
and comparable functional outcome scores at six and 12-months follow-up.
