The aim of this study was to determine whether there is a difference
in the rate of wear between acetabular components positioned within
and outside the ‘safe zones’ of anteversion and inclination angle. We reviewed 100 hips in 94 patients who had undergone primary
total hip arthroplasty (THA) at least ten years previously. Patients
all had the same type of acetabular component with a bearing couple
which consisted of a 28 mm cobalt-chromium head on a highly crosslinked
polyethylene (HXLPE) liner. A supine radiostereometric analysis
(RSA) examination was carried out which acquired anteroposterior
(AP) and lateral paired images. Acetabular component anteversion
and inclination angles were measured as well as total femoral head
penetration, which was divided by the length of implantation to
determine the rate of polyethylene wear.Aims
Patients and Methods
The purpose of this study was to compare the long-term results
of primary total hip arthroplasty (THA) in young patients using
either a conventional (CPE) or a highly cross-linked (HXLPE) polyethylene
liner in terms of functional outcome, incidence of osteolysis, radiological
wear and rate of revision. We included all patients between the ages of 45 and 65 years
who, between January 2000 and December 2001, had undergone a primary
THA for osteoarthritis at our hospital using a CPE or HXLPE acetabular
liner and a 28 mm cobalt-chrome femoral head. From a total of 160 patients, 158 (177 hips) were available for
review (CPE 89; XLPE 88). The mean age, body mass index (BMI) and
follow-up in each group were: CPE: 56.8 years (46 to 65); 30.7 kg/m2 (19
to 58); 13.2 years (2.1 to 14.7) and HXLPE: 55.6 years (45 to 65);
BMI: 30 kg/m2 (18 to 51); 13.1 years (5.7 to 14.4).Aims
Methods
This was a randomised controlled trial studying
the safety of a new short metaphyseal fixation (SMF) stem. We hypothesised
that it would have similar early clinical results and micromovement
to those of a standard-length tapered Synergy metaphyseal fixation
stem. Using radiostereometric analysis (RSA) we compared the two
stems in 43 patients. A short metaphyseal fixation stem was used
in 22 patients and a Synergy stem in 21 patients. No difference
was found in the clinical outcomes pre- or post-operatively between
groups. RSA showed no significant differences two years post-operatively
in mean micromovement between the two stems (except for varus/valgus tilt
at p = 0.05) (subsidence 0.94 mm ( Cite this article:
We evaluated the outcome of primary total hip replacement (THR) in 3290 patients with the primary diagnosis of osteoarthritis at a minimum follow-up of two years. They were stratified into categories of body mass index (BMI) based on the World Health Organisation classification of obesity. Statistical analysis was carried out to determine if there was a difference in the post-operative Western Ontario and McMaster Universities osteoarthritis index, the Harris hip score and the Short-Form-12 outcome based on the BMI. While the pre- and post-operative scores were lower for the group classified as morbidly obese, the overall change in outcome scores suggested an equal if not greater improvement compared with the non-morbidly obese patients. The overall survivorship and rate of complications were similar in the BMI groups although there was a slightly higher rate of revision for sepsis in the morbidly obese group. Morbid obesity does not affect the post-operative outcome after THR, with the possible exception of a marginally increased rate of infection. Therefore withholding surgery based on the BMI is not justified.
This was a safety study where the hypothesis was that the newer-design CPCS femoral stem would demonstrate similar early clinical results and micromovement to the well-established Exeter stem. Both are collarless, tapered, polished cemented stems, the only difference being a slight lateral to medial taper with the CPCS stem. A total of 34 patients were enrolled in a single-blinded randomised controlled trial in which 17 patients received a dedicated radiostereometric CPCS stem and 17 a radiostereometric Exeter stem. No difference was found in any of the outcome measures pre-operatively or post-operatively between groups. At two years, the mean subsidence for the CPCS stem was nearly half that seen for the Exeter stem (0.77 mm (−0.943 to 1.77) and 1.25 mm (0.719 to 1.625), respectively; p = 0.032). In contrast, the mean internal rotation of the CPCS stem was approximately twice that of the Exeter (1.61° (−1.07° to 4.33°) and 0.59° (0.97° to 1.64°), respectively; p = 0.048). Other migration patterns were not significantly different between the stems. The subtle differences in designs may explain the different patterns of migration. Comparable migration with the Exeter stem suggests that the CPCS design will perform well in the long term.
