This paper describes the methodology, validation and reliability
of a new computer-assisted method which uses models of the patient’s
bones and the components to measure their migration and polyethylene
wear from radiographs after total hip arthroplasty (THA). Models of the patient’s acetabular and femoral component obtained
from the manufacturer and models of the patient’s pelvis and femur
built from a single computed tomography (CT) scan, are used by a
computer program to measure the migration of the components and
the penetration of the femoral head from anteroposterior and lateral radiographs
taken at follow-up visits. The program simulates the radiographic
setup and matches the position and orientation of the models to
outlines of the pelvis, the acetabular and femoral component, and
femur on radiographs. Changes in position and orientation reflect
the migration of the components and the penetration of the femoral
head. Validation was performed using radiographs of phantoms simulating
known migration and penetration, and the clinical feasibility of
measuring migration was assessed in two patients.Aims
Materials and Methods
Aims. The aim of this study was to compare the cost-effectiveness of cemented hemiarthroplasty (HA) versus hydroxyapatite-coated uncemented HA for the treatment of displaced intracapsular hip fractures in older adults. Methods. A within-trial economic evaluation was conducted based on data collected from the World Hip Trauma Evaluation 5 (WHiTE 5) multicentre randomized controlled trial in the UK. Resource use was measured over 12 months post-randomization using trial case report forms and participant-completed questionnaires. Cost-effectiveness was reported in terms of incremental cost per quality-adjusted life year (QALY) gained from the NHS and personal social service perspective. Methodological uncertainty was addressed using sensitivity
Aims. The risk of mechanical failure of modular revision hip stems is frequently mentioned in the literature, but little is currently known about the actual clinical failure rates of this type of prosthesis. The current retrospective long-term
Aims. Highly polished stems with force-closed design have shown satisfactory clinical results despite being related to relatively high early migration. It has been suggested that the minimal thickness of cement mantles surrounding the femoral stem should be 2 mm to 4 mm to avoid aseptic loosening. The line-to-line cementing technique of the femoral stem, designed to achieve stem press-fit, challenges this opinion. We compared the migration of a highly polished stem with force-closed design by standard and line-to-line cementing to investigate whether differences in early migration of the stems occur in a clinical study. Methods. In this single-blind, randomized controlled, clinical radiostereometric analysis (RSA) study, the migration pattern of the cemented Corail hip stem was compared between line-to-line and standard cementing in 48 arthroplasties. The primary outcome measure was femoral stem migration in terms of rotation and translation around and along with the X-, Y-, and Z- axes measured using model-based RSA at three, 12, and 24 months. A linear mixed-effects model was used for statistical
The aim of this study was to compare open reduction and internal fixation (ORIF) with revision surgery for the surgical management of Unified Classification System (UCS) type B periprosthetic femoral fractures around cemented polished taper-slip femoral components following primary total hip arthroplasty (THA). Data were collected for patients admitted to five UK centres. The primary outcome measure was the two-year reoperation rate. Secondary outcomes were time to surgery, transfusion requirements, critical care requirements, length of stay, two-year local complication rates, six-month systemic complication rates, and mortality rates. Comparisons were made by the form of treatment (ORIF vs revision) and UCS type (B1 vs B2/B3). Kaplan-Meier survival analysis was performed with two-year reoperation for any reason as the endpoint.Aims
Methods
Aims. Morphological abnormalities are present in patients with developmental dysplasia of the hip (DDH). We studied and compared the pelvic anatomy and morphology between the affected hemipelvis with the unaffected side in patients with unilateral Crowe type IV DDH using 3D imaging and
Aims. We analyzed the acetabular morphology of Crowe type IV hips using CT data to identify a landmark for the ideal placement of the centre of the acetabular component, as assessed by morphometric geometrical
Aims. Osteolysis, secondary to local and systemic physiological effects, is a major challenge in total hip arthroplasty (THA). While osteolytic defects are commonly observed in long-term follow-up, how such lesions alter the distribution of stress is unclear. The aim of this study was to quantitatively describe the biomechanical implication of such lesions by performing subject-specific finite-element (FE)
To assess the sustainability of our institutional
bone bank, we calculated the final product cost of fresh-frozen femoral
head allografts and compared these costs with the use of commercial
alternatives. Between 2007 and 2010 all quantifiable costs associated
with allograft donor screening, harvesting, storage, and administration
of femoral head allografts retrieved from patients undergoing elective
hip replacement were analysed. . From 290 femoral head allografts harvested and stored as full
(complete) head specimens or as two halves, 101 had to be withdrawn.
In total, 104 full and 75 half heads were implanted in 152 recipients.
The calculated final product costs were €1367 per full head. Compared
with the use of commercially available processed allografts, a saving
of at least €43 119 was realised over four-years (€10 780 per year)
resulting in a cost-effective intervention at our institution. Assuming
a price of between €1672 and €2149 per commercially purchased allograft,
breakeven
The cam-type deformity in femoroacetabular impingement
is a 3D deformity. Single measurements using radiographs, CT or
MRI may not provide a true estimate of the magnitude of the deformity.
We performed an
Aims. We hypothesised that the synovial white blood cell (WBC) count
in patients with a late periprosthetic joint infection (PJI) of
the hip would depend on the duration of a patient’s symptoms, and
that the optimal diagnostic threshold would also depend on this
period of time. Patients and Methods. The synovial WBC count and percentage of polymorphonuclear cells
(%PMN), and the serum CRP and ESR levels obtained >
six weeks after
primary THA were compared between 50 infected and 88 non-infected
THAs, and in patients with symptoms for more than or less than two
weeks. Diagnostic thresholds for the synovial WBC count were calculated
using area under the curve calculation. Results. The synovial WBC count was significantly higher in patients with
symptoms for ≤ two weeks compared with those with symptoms for >
two weeks (p = 0.03). The optimal threshold for diagnosing PJI for
the synovial WBC count was 5750 cells/µL (sensitivity 94; specificity
100; PPV 100%; NPV 89%; AUC 99%) and 1556 cells/µL (sensitivity
91; specificity 94; PPV 87% and NPV 97%; AUC 95%), respectively.
The thresholds for the cut-offs based on duration of symptoms improved
the diagnostic performance of this test. Conclusion. This study shows that the diagnostic thresholds for synovial
fluid
We reviewed 264 consecutive primary total hip replacements in 244 patients in which the Harris-Galante I porous-coated acetabular component had been used. The mean follow-up was 95 months (69 to 132). In 221 arthroplasties a 32 mm ceramic head had been used, and in the other 43 one of cobalt-chrome alloy. There were 124 women and 120 men with a mean age at operation of 56.8 years (21 to 83). Survival
Although about 200 000 cementless Zweymüller-Alloclassic total hip arthroplasties (THAs) were carried out worldwide in the last decade, the survival
We retrospectively analysed concentrations of chromium and cobalt ions in samples of synovial fluid and whole blood taken from a group of 92 patients with failed current-generation metal-on-metal hip replacements. We applied acid oxidative digestion to our trace metal
The Birmingham hip resurfacing (BHR) arthroplasty is a metal-on-metal prosthesis for which no medium- or long-term results have been published. Despite this, it is increasing in popularity as an alternative to stemmed prostheses for younger patients. Since the fixation of the socket is conventional, the major concern is long-term failure of the femoral component. This can be predicted by the use of roentgen stereophotogrammetric
Aims. The primary aim of this study was to analyse the position of
the acetabular and femoral components in total hip arthroplasty
undertaken using an anterior surgical approach. . Patients and Methods. In a prospective, single centre study, we used the EOS imaging
system to analyse the position of components following THA performed
via the anterior approach in 102 patients (103 hips) with a mean
age of 64.7 years (. sd. 12.6). Images were taken with patients
in the standing position, allowing measurement of both anatomical
and functional anteversion of the acetabular component. . Results. The mean inclination of the acetabular component was 39° (standard
deviation (. sd). 6), the mean anatomical anteversion was
30° (. sd. 10), and the mean functional anteversion was 31°
(. sd. 8) five days after surgery. The mean anteversion of
the femoral component was 20° (. sd. 11). Anatomical and functional
anteversion of the acetabular component differed by >
10° in 23
(22%) cases. Pelvic tilt was the only pre-operative predictive factor
of this difference. Conclusion. Our study showed that anteversion of the acetabular component
following THA using the anterior approach was greater than the recommended
target value, and that substantial differences were observed in
some patients when measured using two different measurement planes.
If these results are confirmed by further studies, and considering
that the anterior approach is intended to limit the incidence of
dislocation, a new correlation study for each reference plane (anatomical
and functional) will be necessary to define a ‘safe zone’ for use
with the anterior approach. Take home message: EOS imaging system is helpful in the pre-operative
and post-operative radiological
Using a modern cementing technique, we implanted 22 stereolithographic polymeric replicas of the Charnley-Kerboul stem in 11 pairs of human cadaver femora. On one side, the replicas were cemented line-to-line with the largest broach. On the other, one-size undersized replicas were used (radial difference, 0.89 mm . sd. 0.13). CT
Osteolysis is due to particulate wear debris and is responsible for the long-term failure of total hip replacements. It has stimulated the development of alternative joint surfaces such as metal-on-metal or ceramic-on-ceramic implants. Since 1988 the second-generation metal-on-metal implant Metasul has been used in over 60 000 hips.
Revision arthroplasty of the hip is expensive
owing to the increased cost of pre-operative investigations, surgical implants
and instrumentation, protracted hospital stay and drugs. We compared
the costs of performing this surgery for aseptic loosening, dislocation,
deep infection and peri-prosthetic fracture. Clinical, demographic
and economic data were obtained for 305 consecutive revision total
hip replacements in 286 patients performed at a tertiary referral
centre between 1999 and 2008. The mean total costs for revision
surgery in aseptic cases (n = 194) were £11 897 (
We investigated the factors related to the radiological outcome of a transtrochanteric curved varus osteotomy in patients with osteonecrosis of the hip. We reviewed 73 hips in 62 patients with a mean follow-up of 12.4 years (5 to 31.1). There were 28 men and 34 women, with a mean age of 33.3 years (15 to 68) at the time of surgery. The 73 hips were divided into two groups according to their radiological findings: group 1 showed progression of collapse and/or joint-space narrowing; group 2 had neither progressive collapse nor joint-space narrowing. Both of these factors and the radiological outcomes were analysed by a stepwise discriminant