Aims. The Birmingham Hip Resurfacing (BHR) was introduced in 1997 to address the needs of young active patients using a historically proven large-diameter metal-on-metal (MoM) bearing. A single designer surgeon’s consecutive series of 130 patients (144 hips) was previously reported at five and ten years, reporting three and ten failures, respectively. The aim of this study was to extend the follow-up of this original cohort at 25 years. Methods. The study extends the reporting on the first consecutive 144 resurfacing procedures in 130 patients for all indications. All operations were undertaken between August 1997 and May 1998. The mean age at operation was 52.1 years (SD 9.93; 17 to 76), and included 37 female patients (28.5%). Failure was defined as revision of either component for any reason. Kaplan-Meier survival analysis was performed. Routine follow-up with serum metal ion levels, radiographs, and Oxford Hip Scores (OHSs) was undertaken. Results. Overall implant survival was 83.50% (95% confidence interval (CI) 0.79 to 0.90) at 25 years, and the number at risk was 79. Survival in male patients at 25 years was 89.5% (95% CI 0.83 to 0.96) compared to 66.9% for female patients (95% CI 0.51 to 0.83). Ten additional failures occurred in the period of ten to 25 years. These involved an adverse reaction to metal debris in four patients, a periprosthetic femoral neck fracture affecting five patients, and aseptic loosening in one patient. The median chromium levels were 49.50 nmol/l (interquartile range (IQR) 34 to 70), and the median cobalt serum levels were 42 nmol/l (IQR 24.50 to 71.25). The median OHS at last follow-up was 35 (IQR 10 to 48). During the 25-year study period, 29 patients died. Patient survival at 25 years was 75.10% (95% CI 0.67 to 0.83). Conclusion. This study demonstrates that
The first aim of this study was to evaluate whether preoperative renal function is associated with postoperative changes in whole blood levels of metal ions in patients who have undergone a Birmingham Hip Resurfacing (BHR) arthroplasty with a metal-on-metal bearing. The second aim was to evaluate whether exposure to increased cobalt (Co) and chromium (Cr) levels for ten years adversely affected renal function. As part of a multicentre, prospective post-approval study, whole blood samples were sent to a single specialized laboratory to determine Co and Cr levels, and the estimated glomerular filtration rate (eGFR). The study included patients with 117 unrevised unilateral BHRs. There were 36 females (31%). The mean age of the patients at the time of surgery of 51.3 years (SD 6.5), and they all had preoperative one-, four-, five-, and ten-year laboratory data. The mean follow-up was 10.1 years (SD 0.2).Aims
Methods
The aims of the study were to report for a cohort aged younger than 40 years: 1) indications for HRA; 2) patient-reported outcomes in terms of the modified Harris Hip Score (HHS); 3) dislocation rate; and 4) revision rate. This retrospective analysis identified 267 hips from 224 patients who underwent an hip resurfacing arthroplasty (HRA) from a single fellowship-trained surgeon using the direct lateral approach between 2007 and 2019. Inclusion criteria was minimum two-year follow-up, and age younger than 40 years. Patients were followed using a prospectively maintained institutional database.Aims
Methods
Aims. Hip resurfacing remains a potentially valuable surgical procedure for appropriately-selected patients with optimised implant choices. However, concern regarding high early failure rates continues to undermine confidence in use. A large contributor to failure is adverse local tissue reactions around metal-on-metal (MoM) bearing surfaces. Such phenomena have been well-explored around MoM total hip arthroplasties, but comparable data in equivalent hip resurfacing procedures is lacking. In order to define genetic predisposition, we performed a case-control study investigating the role of human leucocyte antigen (HLA) genotype in the development of pseudotumours around
Large-diameter metal-on-metal (MoM) total hip arthroplasty (THA) has demonstrated unexpected high failure rates and pseudotumour formation. The purpose of this prospective cohort study is to report ten-year results in order to establish revision rate, prevalence of pseudotumour formation, and relation with whole blood cobalt levels. All patients were recalled according to the guidelines of the Dutch Orthopaedic Association. They underwent clinical and radiographical assessments (radiograph and CT scan) of the hip prosthesis and whole blood cobalt ion measurements. Overall, 94 patients (95 hips) fulfilled our requirements for a minimum ten-year follow-up.Aims
Methods
Elevated levels of circulating cobalt ions have been linked with a wide range of systemic complications including neurological, endocrine, and cardiovascular symptoms. Case reports of patients with elevated blood cobalt ions have described significant cardiovascular complications including cardiomyopathy. However, correlation between the actual level of circulating cobalt and extent of cardiovascular injury has not previously been performed. This review examines evidence from the literature for a link between elevated blood cobalt levels secondary to metal-on-metal (MoM) hip arthroplasties and cardiomyopathy. Correlation between low, moderate, and high blood cobalt with cardiovascular complications has been considered. Elevated blood cobalt at levels over 250 µg/l have been shown to be a risk factor for developing systemic complications and published case reports document cardiomyopathy, cardiac transplantation, and death in patients with severely elevated blood cobalt ions. However, it is not clear that there is a hard cut-off value and cardiac dysfunction may occur at lower levels. Clinical and laboratory research has found conflicting evidence of cobalt-induced cardiomyopathy in patients with MoM hips. Further work needs to be done to clarify the link between severely elevated blood cobalt ions and cardiomyopathy. Cite this article:
Cardiac magnetic resonance (CMR) was used to assess whether cardiac function or tissue composition was affected in patients with well-functioning metal-on-metal hip resurfacing arthroplasties (MoMHRA) when compared with a group of controls, and to assess if metal ion levels correlated with any of the functional or structural parameters studied. In all, 30 participants with no significant cardiac history were enrolled: 20 patients with well-functioning MoMHRA at mean follow-up of 8.3 years post-procedure (ten unilateral, ten bilateral; 17 men, three women) and a case-matched control group of ten non-MoM total hip arthroplasty patients (six men, four women). The mean age of the whole cohort (study group and controls) at the time of surgery was 50.6 years (41.0 to 64.0). Serum levels of cobalt and chromium were measured, and all patients underwent CMR imaging, including cine, T2* measurements, T1 and T2 mapping, late gadolinium enhancement, and strain measurements.Aims
Patients and Methods
Objectives. We have encountered patients who developed large joint fluid collections with massive elevations in chromium (Cr) and cobalt (Co) concentrations following metal-on-metal (MoM) hip arthroplasties. In some cases, retrieval analysis determined that these ion concentrations could not be explained simply by the wear rates of the components. We hypothesized that these effects may be associated with aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL). Patients and Methods. We examined the influence of the ALVAL grade on synovial fluid Co and Cr concentrations following adjustment for patient and device variables, including volumetric wear rates. Initially restricting the analysis to include only patients with one
To determine ten-year failure rates following 36 mm metal-on-metal
(MoM) Pinnacle total hip arthroplasty (THA), and identify predictors
of failure. We retrospectively assessed a single-centre cohort of 569 primary
36 mm MoM Pinnacle THAs (all Corail stems) followed up since 2012
according to Medicines and Healthcare Products Regulation Agency
recommendations. All-cause failure rates (all-cause revision, and
non-revised cross-sectional imaging failures) were calculated, with predictors
for failure identified using multivariable Cox regression.Aims
Patients and Methods
Our first aim was to determine whether there are significant
changes in the level of metal ions in the blood at mid-term follow-up,
in patients with an Articular Surface Replacement (ASR) arthroplasty.
Secondly, we sought to identify risk factors for any increases. The study involved 435 patients who underwent unilateral, metal-on-metal
(MoM) hip resurfacing (HRA) or total hip arthroplasty (THA). These
patients all had one measurement of the level of metal ions in the
blood before seven years had passed post-operatively (early evaluation)
and one after seven years had passed post-operatively (mid-term evaluation).
Changes in ion levels were tested using a Wilcoxon signed-rank test.
We identified subgroups at the highest risk of increase using a
multivariable linear logistic regression model.Aims
Patients and Methods
The high revision rates of the DePuy Articular Surface Replacement (ASR) and the DePuy ASR XL (the total hip arthroplasty (THA) version) have led to questions over the viability of metal-on-metal (MoM) hip joints. Some designs of MoM hip joint do, however, have reasonable mid-term performance when implanted in appropriate patients. Investigations into the reasons for implant failure are important to offer help with the choice of implants and direction for future implant designs. One way to assess the performance of explanted hip prostheses is to measure the wear (in terms of material loss) on the joint surfaces. In this study, a coordinate measuring machine (CMM) was used to measure the wear on five failed cementless Biomet Magnum/ReCap/ Taperloc large head MoM THAs, along with one Biomet ReCap resurfacing joint. Surface roughness measurements were also taken. The reason for revision of these implants was pain and/or adverse reaction to metal debris (ARMD) and/or elevated blood metal ion levels.Objectives
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
Recently, the use of metal-on-metal articulations
in total hip arthroplasty (THA) has led to an increase in adverse
events owing to local soft-tissue reactions from metal ions and
wear debris. While the majority of these implants perform well,
it has been increasingly recognised that a small proportion of patients
may develop complications secondary to systemic cobalt toxicity
when these implants fail. However, distinguishing true toxicity
from benign elevations in cobalt ion levels can be challenging. The purpose of this two part series is to review the use of cobalt
alloys in THA and to highlight the following related topics of interest:
mechanisms of cobalt ion release and their measurement, definitions
of pathological cobalt ion levels, and the pathophysiology, risk factors
and treatment of cobalt toxicity. Historically, these metal-on-metal
arthroplasties are composed of a chromium-cobalt articulation. The release of cobalt is due to the mechanical and oxidative
stresses placed on the prosthetic joint. It exerts its pathological
effects through direct cellular toxicity. This manuscript will highlight the pathophysiology of cobalt
toxicity in patients with metal-on-metal hip arthroplasties. Take home message: Patients with new or evolving hip symptoms
with a prior history of THA warrant orthopaedic surgical evaluation.
Increased awareness of the range of systemic symptoms associated
with cobalt toxicity, coupled with prompt orthopaedic intervention, may
forestall the development of further complications. Cite this article:
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
We undertook a retrospective cohort study to
determine clinical outcomes following the revision of metal-on-metal (MoM)
hip replacements for adverse reaction to metal debris (ARMD), and
to identify predictors of time to revision and outcomes following
revision. Between 1998 and 2012 a total of 64 MoM hips (mean age
at revision of 57.8 years; 46 (72%) female; 46 (72%) hip resurfacings
and 18 (28%) total hip replacements) were revised for ARMD at one specialist
centre. At a mean follow-up of 4.5 years (1.0 to 14.6) from revision
for ARMD there were 13 hips (20.3%) with post-operative complications
and eight (12.5%) requiring re-revision. The Kaplan–Meier five-year survival rate for ARMD revision was
87.9% (95% confidence interval 78.9 to 98.0; 19 hips at risk). Excluding
re-revisions, the median absolute Oxford hip score (OHS) following
ARMD revision using the percentage method (0% best outcome and 100%
worst outcome) was 18.8% (interquartile range (IQR) 7.8% to 48.3%),
which is equivalent to 39/48 (IQR 24.8/48 to 44.3/48) when using
the modified OHS. Histopathological response did not affect time
to revision for ARMD (p = 0.334) or the subsequent risk of re-revision
(p = 0.879). Similarly, the presence or absence of a contralateral
MoM hip bearing did not affect time to revision for ARMD (p = 0.066)
or the subsequent risk of re-revision (p = 0.178). Patients revised to MoM bearings had higher rates of re-revision
(five of 16 MoM hips re-revised; p = 0.046), but those not requiring
re-revision had good functional results (median absolute OHS 14.6%
or 41.0/48). Short-term morbidity following revision for ARMD was
comparable with previous reports. Caution should be exercised when choosing
bearing surfaces for ARMD revisions. Cite this article:
The October 2014 Hip &
Pelvis Roundup360 looks at: functional acetabular orientation; predicting re-admission following THR; metal ions and resurfacing; lipped liners increase stability; all anaesthetics equal in hip fracture surgery; revision hip surgery in very young patients; and uncemented hips.
The aim of this study was to establish the natural
course of unrevised asymptomatic pseudotumours after metal-on-metal
(MoM) hip resurfacing during a six- to 12-month follow-up period.
We used repeated metal artefact reduction sequence (MARS)-magnetic
resonance imaging (MRI), serum metal ion analysis and clinical examination to
study 14 unrevised hips (mean patient age 52.7 years, 46 to 68,
5 female, 7 male) with a pseudotumour and 23 hips (mean patient
age 52.8 years, 38 to 69, 7 female, 16 male) without a pseudotumour.
The mean post-operative time to the first MARS-MRI scan was 4.3 years
(2.2 to 8.3), and mean time between the first and second MARS-MRI scan
was eight months (6 to 12). At the second MRI scan, the grade of
severity of the pseudotumour had not changed in 35 hips. One new
pseudotumour (Anderson C2 score, moderate) was observed, and one
pseudotumour was downgraded from C2 (moderate) to C1 (mild). In
general, the characteristics of the pseudotumours hardly changed. Repeated MARS-MRI scans within one year in patients with asymptomatic
pseudotumours after
