Plasma levels of cobalt and chromium ions and
Metal Artefact Reduction Sequence (MARS)-MRI scans were performed
on patients with 209 consecutive, unilateral, symptomatic metal-on-metal
(MoM) hip arthroplasties. There was wide variation in plasma cobalt
and chromium levels, and MARS-MRI scans were positive for adverse reaction
to metal debris (ARMD) in 84 hips (40%). There was a significant
difference in the median plasma cobalt and chromium levels between
those with positive and negative MARS-MRI scans (p <
0.001).
Compared with MARS-MRI as the potential reference standard for the
diagnosis of ARMD, the sensitivity of metal ion analysis for cobalt
or chromium with a cut-off of >
7 µg/l was 57%. The specificity was
65%, positive predictive value was 52% and the negative predictive
value was 69% in symptomatic patients. A lowered threshold of >
3.5 µg/l for cobalt and chromium ion levels improved the sensitivity
and negative predictive value to 86% and 74% but at the expense
of specificity (27%) and positive predictive value (44%). Metal ion analysis is not recommended as a sole indirect screening
test in the surveillance of symptomatic patients with a MoM arthroplasty.
The investigating clinicians should have a low threshold for obtaining
cross-sectional imaging in these patients, even in the presence
of low plasma metal ion levels.
This study aims to assess the relationship between history of pseudotumour formation secondary to metal-on-metal (MoM) implants and periprosthetic joint infection (PJI) rate, as well as establish ESR and CRP thresholds that are suggestive of infection in these patients. We hypothesized that patients with a pseudotumour were at increased risk of infection. A total of 1,171 total hip arthroplasty (THA) patients with MoM articulations from August 2000 to March 2014 were retrospectively identified. Of those, 328 patients underwent metal artefact reduction sequence MRI and had minimum two years’ clinical follow-up, and met our inclusion criteria. Data collected included demographic details, surgical indication, laterality, implants used, history of pseudotumour, and their corresponding preoperative ESR (mm/hr) and CRP (mg/dl) levels. Multivariate logistic regression modelling was used to evaluate PJI and history of pseudotumour, and receiver operating characteristic curves were created to assess the diagnostic capabilities of ESR and CRP to determine the presence of infection in patients undergoing revision surgery.Aims
Methods
The primary aim was to determine the influence of COVID-19 on 30-day mortality following hip fracture. Secondary aims were to determine predictors of COVID-19 status on presentation and later in the admission; the rate of hospital acquired COVID-19; and the predictive value of negative swabs on admission. A nationwide multicentre retrospective cohort study was conducted of all patients presenting with a hip fracture to 17 Scottish centres in March and April 2020. Demographics, presentation blood tests, COVID-19 status, Nottingham Hip Fracture Score, management, length of stay, and 30-day mortality were recorded.Aims
Methods
Natural Language Processing (NLP) offers an automated method to extract data from unstructured free text fields for arthroplasty registry participation. Our objective was to investigate how accurately NLP can be used to extract structured clinical data from unstructured clinical notes when compared with manual data extraction. A group of 1,000 randomly selected clinical and hospital notes from eight different surgeons were collected for patients undergoing primary arthroplasty between 2012 and 2018. In all, 19 preoperative, 17 operative, and two postoperative variables of interest were manually extracted from these notes. A NLP algorithm was created to automatically extract these variables from a training sample of these notes, and the algorithm was tested on a random test sample of notes. Performance of the NLP algorithm was measured in Statistical Analysis System (SAS) by calculating the accuracy of the variables collected, the ability of the algorithm to collect the correct information when it was indeed in the note (sensitivity), and the ability of the algorithm to not collect a certain data element when it was not in the note (specificity).Aims
Methods
Postoperative delirium (POD) and postoperative cognitive decline (POCD) are common surgical complications. In the UK, the Best Practice Tariff incentivizes the screening of delirium in patients with hip fracture. Further, a National Hip Fracture Database (NHFD) performance indicator is the reduction in the incidence of POD. To aid in its recognition, we sought to determine factors associated with POD and POCD in patients with hip fractures. We interrogated the NHFD data on patients presenting with hip fractures to our institution from 2016 to 2018. POD was determined using the 4AT score, as recommended by the NHFD and UK Department of Health. POCD was defined as a decline in Abbreviated Mental Test Score (AMTS) of two or greater. Using logistic regression, we adjusted for covariates to identify factors associated with POD and POCD.Aims
Methods
Abnormal femoral torsion (FT) is increasingly recognized as an additional cause for femoroacetabular impingement (FAI). It is unknown if in-toeing of the foot is a specific diagnostic sign for increased FT in patients with symptomatic FAI. The aims of this study were to determine: 1) the prevalence and diagnostic accuracy of in-toeing to detect increased FT; 2) if foot progression angle (FPA) and tibial torsion (TT) are different among patients with abnormal FT; and 3) if FPA correlates with FT. A retrospective, institutional review board (IRB)-approved, controlled study of 85 symptomatic patients (148 hips) with FAI or hip dysplasia was performed in the gait laboratory. All patients had a measurement of FT (pelvic CT scan), TT (CT scan), and FPA (optical motion capture system). We allocated all patients to three groups with decreased FT (< 10°, 37 hips), increased FT (> 25°, 61 hips), and normal FT (10° to 25°, 50 hips). Cluster analysis was performed.Aims
Patients and Methods
The aim of this study was to determine if the Oxford Knee and Hip Score (OKHS) can accurately predict when a primary knee or hip referral is deemed nonsurgical We retrospectively reviewed pre-consultation OKHS for all consecutive primary total knee arthroplasty (TKA) and total hip arthroplasty (THA) consultations of a single surgeon over three years. The 1436 knees (1016 patients) and 478 hips (388 patients) included were categorized based on the surgeon’s decision into those offered surgery during the first consultation Aims
Patients and Methods
A borderline dysplastic hip can behave as either stable or unstable and this makes surgical decision making challenging. While an unstable hip may be best treated by acetabular reorientation, stable hips can be treated arthroscopically. Several imaging parameters can help to identify the appropriate treatment, including the Femoro-Epiphyseal Acetabular Roof (FEAR) index, measured on plain radiographs. The aim of this study was to assess the reliability and the sensitivity of FEAR index on MRI compared with its radiological measurement. The technique of measuring the FEAR index on MRI was defined and its reliability validated. A retrospective study assessed three groups of 20 patients: an unstable group of ‘borderline dysplastic hips’ with lateral centre edge angle (LCEA) less than 25° treated successfully by periacetabular osteotomy; a stable group of ‘borderline dysplastic hips’ with LCEA less than 25° treated successfully by impingement surgery; and an asymptomatic control group with LCEA between 25° and 35°. The following measurements were performed on both standardized radiographs and on MRI: LCEA, acetabular index, femoral anteversion, and FEAR index.Aims
Patients and Methods
Prosthetic joint infection (PJI) and aseptic loosening in total hip arthroplasty (THA) can present with pain and osteolysis. The Musculoskeletal Infection Society (MSIS) has provided criteria for the diagnosis of PJI. The aim of our study was to analyze the utility of F18-fluorodeoxyglucose (FDG) positron emission tomography (PET) CT scan in the preoperative diagnosis of septic loosening in THA, based on the current MSIS definition of prosthetic joint infection. A total of 130 painful unilateral cemented THAs with a mean follow-up of 5.17 years (Aims
Patients and Methods
This study of patients with osteoarthritis (OA) of the hip aimed to: 1) characterize the contribution of the hip, spinopelvic complex, and lumbar spine when moving from the standing to the sitting position; 2) assess whether abnormal spinopelvic mobility is associated with worse symptoms; and 3) identify whether spinopelvic mobility can be predicted from static anatomical radiological parameters. A total of 122 patients with end-stage OA of the hip awaiting total hip arthroplasty (THA) were prospectively studied. Patient-reported outcome measures (PROMs; Oxford Hip Score, Oswestry Disability Index, and Veterans RAND 12-Item Health Survey Score) and clinical data were collected. Sagittal spinopelvic mobility was calculated as the change from the standing to sitting position using the lumbar lordosis angle (LL), sacral slope (SS), pelvic tilt (PT), pelvic-femoral angle (PFA), and acetabular anteinclination (AI) from lateral radiographs. The interaction of the different parameters was assessed. PROMs were compared between patients with normal spinopelvic mobility (10° ≤ ∆PT ≤ 30°) or abnormal spinopelvic mobility (stiff: ∆PT < ± 10°; hypermobile: ∆PT > ± 30°). Multiple regression and receiver operating characteristic (ROC) curve analyses were used to test for possible predictors of spinopelvic mobility.Aims
Patients and Methods
Leucocyte esterase (LE) has been shown to be an accurate marker of prosthetic joint infection (PJI), and has been proposed as an alternative to frozen section (FS) histology for intraoperative diagnosis. In this study, the intraoperative assessment of LE was compared with FS histology for the diagnosis of prosthetic hip infection. A total of 119 patients undergoing revision total hip arthroplasty (THA) between June 2015 and December 2017 were included in the study. There were 56 men and 63 women with a mean age of 66.2 years (27 to 88). Synovial fluid was collected before arthrotomy for the assessment of LE using enzymatic colourimetric strips. Between five and six samples were stained with haematoxylin and eosin for FS histology, and considered suggestive of infection when at least five polymorphonuclear leucocytes were found in five high-power fields.Aims
Patients and Methods
The purpose of this study was to determine the sensitivity, specificity
and predictive values of previously reported thresholds of proximal
translation and sagittal rotation of cementless acetabular components
used for revision total hip arthroplasty (THA) at various times
during early follow-up. Migration of cementless acetabular components was measured retrospectively
in 84 patients (94 components) using Ein-Bild-Rontgen-Analyse (EBRA-Cup)
in two groups of patients. In Group A, components were recorded
as not being loose intra-operatively at re-revision THA (52 components/48
patients) and Group B components were recorded to be loose at re-revision
(42 components/36 patients).Aims
Patients and Methods
The purpose of this study was to validate the diagnosis of periprosthetic
joint infection (PJI) in the Danish Hip Arthroplasty Register (DHR). We identified a cohort of patients from the DHR who had undergone
primary total hip arthroplasty (THA) since 1 January 2005 and followed
them until first-time revision, death, emigration or until 31 December
2012. Revision for PJI, as registered in the DHR, was validated against
a benchmark which included information from microbiology databases,
prescription registers, clinical biochemistry registers and clinical
records. We estimated the sensitivity, specificity, positive predictive
value (PPV) and negative predictive value (NPV) for PJI in the DHR
alone and in the DHR when combined with microbiology databases.Aims
Patients and Methods
We investigated whether blood metal ion levels could effectively
identify patients with bilateral Birmingham Hip Resurfacing (BHR)
implants who have adverse reactions to metal debris (ARMD). Metal ion levels in whole blood were measured in 185 patients
with bilateral BHRs. Patients were divided into those with ARMD
who either had undergone a revision for ARMD or had ARMD on imaging
(n = 30), and those without ARMD (n = 155). Receiver operating characteristic
analysis was used to determine the optimal thresholds of blood metal
ion levels for identifying patients with ARMD.Aims
Patients and Methods
The diagnosis of periprosthetic joint infection (PJI) is difficult and requires a battery of tests and clinical findings. The purpose of this review is to summarize all current evidence for common and new serum biomarkers utilized in the diagnosis of PJI. We searched two literature databases, using terms that encompass all hip and knee arthroplasty procedures, as well as PJI and statistical terms reflecting diagnostic parameters. The findings are summarized as a narrative review.Objectives
Methods
This study aimed to determine the diagnostic performance of radiographic
criteria to detect aseptic acetabular loosening after revision total
hip arthroplasty (THA). Secondary aims were to determine the predictive
values of different thresholds of migration and to determine the
predictive values of radiolucency criteria. Acetabular component migration to re-revision was measured retrospectively
using Ein-Bild-Rontgen-Analyse (EBRA-Cup) and manual measurements
(Sutherland method) in two groups: Group A, 52 components (48 patients) found
not loose at re-revision and Group B, 42 components (36 patients)
found loose at re-revision between 1980 and 2015. The presence and
extent of radiolucent lines was also assessed.Aims
Patients and Methods
Acetabular labral tears and associated intra-articular
pathology of the hip have been recognised as a source of symptoms.
However, it is now appreciated that there is a relatively high prevalence
of asymptomatic labral tears. In this study, 70 young asymptomatic
adult volunteers with a mean age of 26 years (19 to 41) were recruited
and underwent three tesla non-arthrographic MR scans. There were
47 women (67.1%) and 23 men (32.9%). Labral tears were found in 27 volunteers (38.6%); these were
an isolated finding in 16 (22.9%) and were associated with other
intra-articular pathology in the remaining 11 (15.7%) volunteers.
Furthermore, five (7.1%) had intra-articular pathology without an
associated labral tear. Given the high prevalence of labral pathology in the asymptomatic
population, it is important to confirm that a patient's symptoms
are due to the demonstrated abnormalities when considering surgery. Cite this article:
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. 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.Aims
Patients and Methods
Alarm over the reported high failure rates for metal-on-metal (MoM) hip implants as well as their potential for locally aggressive Adverse Reactions to Metal Debris (ARMDs) has prompted government agencies, internationally, to recommend the monitoring of patients with MoM hip implants. Some have advised that a blood ion level >7 µg/L indicates potential for ARMDs. We report a systematic review and meta-analysis of the performance of metal ion testing for ARMDs. We searched MEDLINE and EMBASE to identify articles from which it was possible to reconstruct a 2 × 2 table. Two readers independently reviewed all articles and extracted data using explicit criteria. We computed a summary receiver operating curve using a Bayesian random-effects hierarchical model.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 aims of this study were to compare the diagnostic test characteristics
of ultrasound alone, metal artefact reduction sequence MRI (MARS-MRI)
alone, and ultrasound combined with MARS-MRI for identifying intra-operative
pseudotumours in metal-on-metal hip resurfacing (MoMHR) patients
undergoing revision surgery. This retrospective diagnostic accuracy study involved 39 patients
(40 MoMHRs). The time between imaging modalities was a mean of 14.6
days (0 to 90), with imaging performed at a mean of 5.3 months (0.06
to 12) before revision. The prevalence of intra-operative pseudotumours
was 82.5% (n = 33).Aims
Methods
The aim of this study was to assess the role
of synovial C-reactive protein (CRP) in the diagnosis of chronic periprosthetic
hip infection. We prospectively collected synovial fluid from 89
patients undergoing revision hip arthroplasty and measured synovial
CRP, serum CRP, erythrocyte sedimentation rate (ESR), synovial white
blood cell (WBC) count and synovial percentages of polymorphonuclear
neutrophils (PMN). Patients were classified as septic or aseptic
by means of clinical, microbiological, serum and synovial fluid
findings. The high viscosity of the synovial fluid precluded the
analyses in nine patients permitting the results in 80 patients
to be studied. There was a significant difference in synovial CRP
levels between the septic (n = 21) and the aseptic (n = 59) cohort.
According to the receiver operating characteristic curve, a synovial
CRP threshold of 2.5 mg/l had a sensitivity of 95.5% and specificity
of 93.3%. The area under the curve was 0.96. Compared with serum
CRP and ESR, synovial CRP showed a high diagnostic value. According
to these preliminary results, synovial CRP may be a useful parameter
in diagnosing chronic periprosthetic hip infection. Cite this article:
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 analysis. A total of 12 hips were categorised as group 1 and 61 as group 2. Both the post-operative intact ratio and the localisation of the necrotic lesion correlated with the radiological outcome. The cut-off point of the postoperative intact ratio to prevent the progression of collapse was 33.6%, and the cut-off point to prevent both the progression of collapse and joint-space narrowing was 41.9%. The results of this study indicate that a post-operative intact ratio of 33.0% is necessary if a satisfactory outcome is to be achieved after this varus osteotomy.
Two major complications of hip replacement are loosening and infection. Reliable differentiation between these pathological processes is difficult since both may be accompanied by similar symptoms. Our aim was to assess the diagnostic ability of triple-phase bone scanning (TPBS) and positron-emission tomography (PET) to detect and differentiate these complications in patients with a hip arthroplasty. Both TPBS and PET were performed in 63 patients (92 prostheses). The radiotracer for PET imaging was 18F-fluorodeoxyglucose (FDG). Image interpretation was performed according to qualitative and quantitative criteria although the final diagnosis was based upon either surgical findings or clinical follow-up. The sensitivity, specificity and accuracy of PET was 0.94, 0.95 and 0.95 respectively, compared with 0.68, 0.76 and 0.74 for TPBS. We found that an image interpretation based exclusively upon quantitative criteria was inappropriate because of its low selectivity. The histological examination indicated that increased periprosthetic uptake of FDG in patients with aseptic loosening was caused by wear-induced polyethylene particles and the subsequent growth of aggressive granulomatous tissue.
Pseudotumour is a rare but important complication of metal-on-metal hip resurfacing that occurs much more commonly in women than in men. We examined the relationship between head-neck ratio (HNR) and pseudotumour formation in 18 resurfaced hips (18 patients) revised for pseudotumour and 42 asymptomatic control resurfaced hips (42 patients). Patients in whom pseudotumour formation had occurred had higher pre-operative HNR than the control patients (mean 1.37 ( We suggest that reducing the size of the femoral head, made possible by a high pre-operative HNR, increases the risk of impingement and edge loading, and may contribute to high wear and pseudotumour formation. As the incidence of pseudotumour is low in men, it appears safe to perform resurfacing in men. However, this study suggests that it is also reasonable to resurface in women with a pre-operative HNR ≤ 1.3.
We report the follow-up at 12 years of the use of the Elite Plus total hip replacement (THR). We have previously reported the results at a mean of 6.4 years. Of the 217 patients (234 THRs), 83 had died and nine had been lost to follow-up. The patients were reviewed radiologically and clinically using the Oxford hip score. Of the 234 THRs, 19 (8.1%) had required a revision by the final follow-up in all but one for aseptic loosening. Survivorship analysis for revision showed a survival of 93.9% (95% confidence interval (CI) 89.2 to 96.5) at ten years, and of 88.0% (95% CI 81.8 to 92.3) at 12 years. At the final follow-up survival analysis showed that 37% (95% CI 37.3 to 44.7) of the prostheses had either failed radiologically or had been revised. Patients with a radiologically loose femoral component had a significantly poorer Oxford hip score than those with a well-fixed component (p = 0.03). Radiological loosening at 6.4 years was predictive of failure at 12 years. Medium-term radiographs and clinical scores should be included in the surveillance of THR to give an early indication of the performance of specific implants.
