Aims. Cementless acetabular components rely on press-fit fixation for initial stability. In certain cases, initial stability is more difficult to obtain (such as during revision). No current study evaluates how a surgeon’s impaction technique (mallet mass, mallet velocity, and number of strikes) may affect component fixation. This study seeks to answer the following research questions: 1) how does impaction technique affect a) bone strain generation and deterioration (and hence implant stability) and b) seating in different density bones?; and 2) can an impaction technique be recommended to minimize risk of implant loosening while ensuring seating of the acetabular component?. Methods. A custom drop tower was used to simulate surgical strikes seating acetabular components into synthetic bone. Strike velocity and drop mass were varied. Synthetic bone strain was measured using strain gauges and stability was assessed via push-out tests. Polar gap was measured using optical trackers. Results. A phenomenon of strain deterioration was identified if an excessive number of strikes was used to seat a component. This effect was most pronounced in low-density bone at high strike velocities. Polar gap was reduced with increasing strike mass and velocity. Conclusion. A high mallet mass with low strike velocity resulted in satisfactory implant stability and polar gap, while minimizing the risk of losing stability due to over-striking. Extreme caution not to over-strike must be
This study investigates the use of the metabolic equivalent of task (MET) score in a young hip arthroplasty population, and its ability to capture additional benefit beyond the ceiling effect of conventional patient-reported outcome measures. From our electronic database of 751 hip arthroplasty procedures, 221 patients were included. Patients were excluded if they had revision surgery, an alternative hip procedure, or incomplete data either preoperatively or at one-year follow-up. Included patients had a mean age of 59.4 years (SD 11.3) and 54.3% were male, incorporating 117 primary total hip and 104 hip resurfacing arthroplasty operations. Oxford Hip Score (OHS), EuroQol five-dimension questionnaire (EQ-5D), and the MET were recorded preoperatively and at one-year follow-up. The distribution was examined reporting the presence of ceiling and floor effects. Validity was assessed correlating the MET with the other scores using Spearman’s rank correlation coefficient and determining responsiveness. A subgroup of 93 patients scoring 48/48 on the OHS were analyzed by age, sex, BMI, and preoperative MET using the other metrics to determine if differences could be established despite scoring identically on the OHS.Aims
Methods
Femoroacetabular Junction Impingement (FAI) describes abnormalities
in the shape of the femoral head–neck junction, or abnormalities
in the orientation of the acetabulum. In the short term, FAI can
give rise to pain and disability, and in the long-term it significantly increases
the risk of developing osteoarthritis. The Femoroacetabular Impingement
Trial (FAIT) aims to determine whether operative or non-operative
intervention is more effective at improving symptoms and preventing
the development and progression of osteoarthritis. FAIT is a multicentre superiority parallel two-arm randomised
controlled trial comparing physiotherapy and activity modification
with arthroscopic surgery for the treatment of symptomatic FAI.
Patients aged 18 to 60 with clinical and radiological evidence of
FAI are eligible. Principal exclusion criteria include previous
surgery to the index hip, established osteoarthritis (Kellgren–Lawrence
≥ 2), hip dysplasia (centre-edge angle <
20°), and completion
of a physiotherapy programme targeting FAI within the previous 12
months. Recruitment will take place over 24 months and 120 patients
will be randomised in a 1:1 ratio and followed up for three years.
The two primary outcome measures are change in hip outcome score
eight months post-randomisation (approximately six-months post-intervention
initiation) and change in radiographic minimum joint space width
38 months post-randomisation. ClinicalTrials.gov: NCT01893034. Cite this article: Aims
Methods
Total hip replacement causes a short-term increase
in the risk of mortality. It is important to quantify this and to identify
modifiable risk factors so that the risk of post-operative mortality
can be minimised. We performed a systematic review and critical
evaluation of the current literature on the topic. We identified
32 studies published over the last 10 years which provide either
30-day or 90-day mortality data. We estimate the pooled incidence
of mortality during the first 30 and 90 days following hip replacement
to be 0.30% (95% CI 0.22 to 0.38) and 0.65% (95% CI 0.50 to 0.81),
respectively. We found strong evidence of a temporal trend towards
reducing mortality rates despite increasingly co-morbid patients.
The risk factors for early mortality most commonly identified are
increasing age, male gender and co-morbid conditions, particularly
cardiovascular disease. Cardiovascular complications appear to have
overtaken fatal pulmonary emboli as the leading cause of death after
hip replacement. Cite this article:
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
