This study compared the primary stability of two commercially
available acetabular components from the same manufacturer, which
differ only in geometry; a hemispherical and a peripherally enhanced
design (peripheral self-locking (PSL)). The objective was to determine
whether altered geometry resulted in better primary stability. Acetabular components were seated with 0.8 mm to 2 mm interference
fits in reamed polyethylene bone substrate of two different densities
(0.22 g/cm3 and 0.45 g/cm3). The primary stability
of each component design was investigated by measuring the peak
failure load during uniaxial pull-out and tangential lever-out tests.Objective
Methods
To investigate psychosocial and biomedical outcomes following
total hip replacement (THR) and to identify predictors of recovery
from THR. Patients with osteoarthritis (OA) on the waiting list for primary
THR in North West England were assessed pre-operatively and at six
and 12 months post-operatively to investigate psychosocial and biomedical
outcomes. Psychosocial outcomes were anxiety and depression, social
support and health-related quality of life (HRQoL). Biomedical outcomes
were pain, physical function and stiffness. The primary outcome
was the Short-Form 36 (SF-36) Health Survey Total Physical Function.
Potential predictors of outcome were age, sex, body mass index,
previous joint replacement, involvement in the decision for THR,
any comorbidities, any complications, type of medication, and pre-operative
ENRICHD Social Support Instrument score, Hospital Anxiety and Depression
scores and Western Ontario and McMaster Universities osteoarthritis index
score.Objectives
Methods
We aimed to determine the effect of surgical approach on the
histology of the femoral head following resurfacing of the hip. We performed a histological assessment of the bone under the
femoral component taken from retrieval specimens of patients having
revision surgery following resurfacing of the hip. We compared the
number of empty lacunae in specimens from patients who had originally
had a posterior surgical approach with the number in patients having alternative
surgical approaches.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
The aims of this piece of work were to: 1) record the background
concentrations of blood chromium (Cr) and cobalt (Co) concentrations
in a large group of subjects; 2) to compare blood/serum Cr and Co
concentrations with retrieved metal-on-metal (MoM) hip resurfacings;
3) to examine the distribution of Co and Cr in the serum and whole
blood of patients with MoM hip arthroplasties; and 4) to further
understand the partitioning of metal ions between the serum and
whole blood fractions. A total of 3042 blood samples donated to the local transfusion
centre were analysed to record Co and Cr concentrations. Also, 91
hip resurfacing devices from patients who had given pre-revision
blood/serum samples for metal ion analysis underwent volumetric
wear assessment using a coordinate measuring machine. Linear regression analysis
was carried out and receiver operating characteristic curves were
constructed to assess the reliability of metal ions to identify
abnormally wearing implants. The relationship between serum and
whole blood concentrations of Cr and Co in 1048 patients was analysed
using Bland-Altman charts. This relationship was further investigated
in an Objectives
Methods
The number of surgical procedures performed each year to treat
femoroacetabular impingement (FAI) continues to rise. Although there
is evidence that surgery can improve symptoms in the short-term,
there is no evidence that it slows the development of osteoarthritis
(OA). We performed a feasibility study to determine whether patient
and surgeon opinion was permissive for a Randomised Controlled Trial
(RCT) comparing operative with non-operative treatment for FAI. Surgeon opinion was obtained using validated questionnaires at
a Specialist Hip Meeting (n = 61, 30 of whom stated that they routinely
performed FAI surgery) and patient opinion was obtained from clinical
patients with a new diagnosis of FAI (n = 31).Objectives
Methods
The aim of this review is to evaluate the current
available literature evidencing on peri-articular hip endoscopy
(the third compartment). A comprehensive approach has been set on
reports dealing with endoscopic surgery for recalcitrant trochanteric
bursitis, snapping hip (or coxa-saltans; external and internal),
gluteus medius and minimus tears and endoscopy (or arthroscopy)
after total hip arthroplasty. This information can be used to trigger
further research, innovation and education in extra-articular hip
endoscopy.
Femoroacetabular impingement (FAI) causes pain
and chondrolabral damage via mechanical overload during movement
of the hip. It is caused by many different types of pathoanatomy,
including the cam ‘bump’, decreased head–neck offset, acetabular
retroversion, global acetabular overcoverage, prominent anterior–inferior
iliac spine, slipped capital femoral epiphysis, and the sequelae
of childhood Perthes’ disease. Both evolutionary and developmental factors may cause FAI. Prevalence
studies show that anatomic variations that cause FAI are common
in the asymptomatic population. Young athletes may be predisposed
to FAI because of the stress on the physis during development. Other
factors, including the soft tissues, may also influence symptoms and
chondrolabral damage. FAI and the resultant chondrolabral pathology are often treated
arthroscopically. Although the results are favourable, morphologies
can be complex, patient expectations are high and the surgery is
challenging. The long-term outcomes of hip arthroscopy are still
forthcoming and it is unknown if treatment of FAI will prevent arthrosis.
The Kaplan-Meier estimation is widely used in orthopedics to
calculate the probability of revision surgery. Using data from a
long-term follow-up study, we aimed to assess the amount of bias
introduced by the Kaplan-Meier estimator in a competing risk setting. We describe both the Kaplan-Meier estimator and the competing
risk model, and explain why the competing risk model is a more appropriate
approach to estimate the probability of revision surgery when patients
die in a hip revision surgery cohort. In our study, a total of 62 acetabular
revisions were performed. After a mean of 25 years, no patients
were lost to follow-up, 13 patients had undergone revision surgery
and 33 patients died of causes unrelated to their hip.Objectives
Methods
The Oxford hip score (OHS) is a 12-item questionnaire designed
and developed to assess function and pain from the perspective of
patients who are undergoing total hip replacement (THR). The OHS
has been shown to be consistent, reliable, valid and sensitive to
clinical change following THR. It has been translated into different
languages, but no adequately translated, adapted and validated Danish
language version exists. The OHS was translated and cross-culturally adapted into Danish
from the original English version, using methods based on best-practice
guidelines. The translation was tested for psychometric quality
in patients drawn from a cohort from the Danish Hip Arthroplasty
Register (DHR).Objectives
Methods
The accuracy and precision of two new methods of model-based
radiostereometric analysis (RSA) were hypothesised to be superior
to a plain radiograph method in the assessment of polyethylene (PE)
wear. A phantom device was constructed to simulate three-dimensional
(3D) PE wear. Images were obtained consecutively for each simulated
wear position for each modality. Three commercially available packages
were evaluated: model-based RSA using laser-scanned cup models (MB-RSA),
model-based RSA using computer-generated elementary geometrical
shape models (EGS-RSA), and PolyWare. Precision (95% repeatability
limits) and accuracy (Root Mean Square Errors) for two-dimensional
(2D) and 3D wear measurements were assessed.Objectives
Methods
Over recent years hip arthroscopic surgery has
evolved into one of the most rapidly expanding fields in orthopaedic surgery.
Complications are largely transient and incidences between 0.5%
and 6.4% have been reported. However, major complications can and
do occur. This article analyses the reported complications and makes recommendations
based on the literature review and personal experience on how to
minimise them.
To study the vascularity and bone metabolism of the femoral head/neck
following hip resurfacing arthroplasty, and to use these results
to compare the posterior and the trochanteric-flip approaches. In our previous work, we reported changes to intra-operative
blood flow during hip resurfacing arthroplasty comparing two surgical
approaches. In this study, we report the vascularity and the metabolic
bone function in the proximal femur in these same patients at one
year after the surgery. Vascularity and bone function was assessed
using scintigraphic techniques. Of the 13 patients who agreed to
take part, eight had their arthroplasty through a posterior approach
and five through a trochanteric-flip approach.Objectives
Methods
Pseudotumours (abnormal peri-prosthetic soft-tissue reactions)
following metal-on-metal hip resurfacing arthroplasty (MoMHRA) have
been associated with elevated metal ion levels, suggesting that
excessive wear may occur due to edge-loading of these MoM implants.
This study aimed to quantify The duration and magnitude of edge-loading Objectives
Methods
An ongoing prospective study to investigate failing metal-on-metal
hip prostheses was commenced at our centre in 2008. We report on
the results of the analysis of the first consecutive 126 failed
mated total hip prostheses from a single manufacturer. Analysis was carried out using highly accurate coordinate measuring
to calculate volumetric and linear rates of the articular bearing
surfaces and also the surfaces of the taper junctions. The relationship
between taper wear rates and a number of variables, including bearing
diameter and orientation of the acetabular component, was investigated.Objectives
Methods
Metal-on-metal (MoM) hip resurfacing was introduced into clinical
practice because it was perceived to be a better alternative to
conventional total hip replacement for young and active patients.
However, an increasing number of reports of complications have arisen
focusing on design and orientation of the components, the generation
of metallic wear particles and serum levels of metallic ions. The
procedure introduced a combination of two elements: large-dimension
components and hard abrasive particles of metal wear. The objective
of our study was to investigate the theory that microseparation
of the articular surfaces draws in a high volume of bursal fluid
and its contents into the articulation, and at relocation under
load would generate high pressures of fluid ejection, resulting
in an abrasive water jet. This theoretical concept using MoM resurfacing components (head
diameter 55 mm) was modelled mathematically and confirmed experimentally
using a material-testing machine that pushed the head into the cup
at a rate of 1000 mm/min until fully engaged.Objectives
Methods
The purpose of this study was to assess N-acetyl aspartate changes
in the thalamus in patients with osteoarthritis of the hip using
proton magnetic resonance spectroscopy. Nine patients with osteoarthritis of the hip (symptomatic group,
nine women; mean age 61.4 years (48 to 78)) and nine healthy volunteers
(control group, six men, three women; mean age 30.0 years (26 to
38)) underwent proton magnetic resonance spectroscopy to assess
the changes of N-acetyl aspartate in the thalamus. Objectives
Methods