Aims. We investigated whether
Purpose. Total shoulder arthroplasty (TSA) has become a successful treatment option for degenerative shoulder disease. With the increasing incidence in primary TSA procedures during the last decades, strategies to improve implant longevity become more relevant. Implant failure is mainly associated with mechanical or biological causes. Chronic inflammation as a response to wear particle exposure is regarded as a main biological mechanism leading to implant failure. Metal ions released by fretting and corrosion at modular taper connections of orthopedic implants can cause cell-mediated hypersensitivity reactions and might lead to aseptic loosening. Modularity is also commonly used in total shoulder replacement. However, little is known about metal ion exposure in patients following TSA. The objective of this study was to determine in-vivo
A concern of metal on metal hip resurfacing arthroplasty is long term exposure to Cobalt (Co) and Chromium (CR) wear debris from the bearing. This study compares whole
High short-term failure rates have been observed with a number of metal-on-metal (MoM) hip designs. Most patients require follow-up with
Metal ion levels are used to track the performance of metal containing bearings in hip replacement patients. Changes in whole
The search for the ideal bearing surface in Total Hip Replacements continues. The current ‘best’ materials are felt to be combinations of metal, ceramics and cross-linked polyethylene. Laboratory studies suggest that ceramic-on-metal articulations may provide distinct advantages. This study aims to identify the best bearing surface combination with the lowest adverse side effect profile. Between February 2004 and September 2007, 164 hips were replaced in 142 patients. 39% were male and 69% were female. The average age at surgery was 53 years (17-72 years). Follow-up assessment included radiographs, the Harris Hip Score and whole blood samples for metal ion levels. Complications to date included 3 hips which needed femoral revision because of surgery related factors, and 3 cases of sepsis of which 1 settled and 2 needed revision. One hip needed revision of head and liner to a larger bearing size for recurrent dislocations, and is no longer being followed up for
Objectives. 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. Methods. 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. Results. Our literature search returned 575 unique articles; only six met inclusion criteria defined a priori. The discriminative capacity of ion tests was homogeneous across studies but that there was substantial cut-point heterogeneity. Our best estimate of the “true” area under curve (AUC) for metal ion testing is 0.615, with a 95% credible interval of 0.480 to 0.735, thus we can state that the probability that metal ion testing is actually clinically useful with an AUC ≥ 0.75 is 1.7%. Conclusion. Metal ion levels are not useful as a screening test for identifying high risk patients because ion testing will either lead to a large burden of false positive patients, or otherwise marginally modify the pre-test probability. With the availability of more accurate non-invasive tests, we did not find any evidence for using blood ion levels to diagnose symptomatic patients. Cite this article: M. Pahuta, J. M. Smolders, J. L. van Susante, J. Peck, P. R. Kim, P. E. Beaule.
There are several component position and design variables that increase the risk of edge loading and high wear in metal-on-metal hip resurfacing (MOM-HR). In this study we combined all of these variables to calculate the ‘contact patch to rim distance’ (CPRD) in patients undergoing revision of their MOM-HR. We then determined whether CPRD was more strongly correlated with component wear and
Introduction. A metal ion study was undertaken in patients who had received an articular surface replacement. The design of these components is optimised in line with lubrication theory and produces low levels of wear in hip joint simulators. Methods. Patients were recruited in four centres. Whole blood samples were analysed for metal ion levels using high resolution ICP-MS (inductively coupled plasma mass spectrophotometry). A total of 75 patients was enrolled into the study and 65 and 47 patients were assessed after 12 and 24 months implantation respectively. Results are included irrespective of clinical outcome. Results. The 12 and 24 month median ion levels were 1.4 μg/l and 1.6 μg/l respectively for chromium and 1.5(μg/l and 1.6 μg/l respectively for cobalt. The pre-operative levels were 0.38(μg/l and 0.34(μg/l for chromium and cobalt respectively. Twenty-seven percent of patients had a pre-operative chromium level that was higher than the 24 month median level. Similarly the value for cobalt was seven percent. However close examination of the data shows that it is skewed by 6 outliers with cobalt or chromium levels greater than 10(μg/l after 24 months implantation. This appears to be related to acetabular component placement. Patients with acetabular components implanted at a high inclination angle (>55deg) are more likely to have elevated metal ion levels compared with a standard angle (<55deg). In the 24 month group two patients (both outliers) have been revised. Furthermore, the high metal ion levels at 24 months could be predicted by intermediate levels after 12 months. Conversely those levels below 10ug/l had already stabilised after 12 months in vivo. Conclusion. Large diameter metal-on-metal bearing with optimised tolerances can produce very low
Objectives. 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. Methods. 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 in vitro study during which human blood was
spiked with trivalent and hexavalent Cr, the serum then separated
and the fractions analysed. Results. Only one patient in the transfusion group was found to have a
blood Co >
2 µg/l. Blood/Serum Cr and Co concentrations were reliable
indicators of abnormal wear. Blood Co appeared to be the most useful
clinical test, with a concentration of 4.5 µg/l showing sensitivity
and specificity for the detection of abnormal wear of 94% and 95%, respectively.
Generated metal ions tended to fill the serum compartment preferentially in
vivo and this was replicated in the in vitro study
when blood was spiked with trivalent Cr and bivalent Co. Conclusions.
Background: Definitive cup position for the reduction of
Background:
The search for the ideal bearing surfaces to be used in Total Hip Replacement continues. The current “best” materials are felt to be various combinations of metal, ceramics and cross-linked polyethylene. Laboratory studies suggest that ceramic-on-metal articulations may provide distinct advantages. This study aims to identify the best combination with the lowest side effect profile. In February 2004 a prospective randomised trial on different bearing surfaces was started. The combinations selected were ceramic-on-cross-linked polyethylene, ceramic-on-ceramic, metal-on-metal and ceramic-on-metal. Institutional ethics clearance was obtained. In all patients uncemented femoral stems are used, with an uncemented porocoated acetabular shell. A uniform 28mm femoral head size was selected. Blood samples have been taken to measure the metal ion concentrations in all patients. These are measured pre operatively, and repeated at follow up visits at 3 months and 1 year, with further follow up at 3,5 and 10 years post operatively. Whole blood ion levels are measured using a graphite furnace atomic absorption spectrometer. Between February 2004 and April 2006 one hundred and ten hips have undergone total hip replacement. There are 105 patients (5 bilateral). 40% are males and 60% female. The average age at operation is 52 years (17 to 72). 49% hips are left and 51% right. Follow up includes blood samples and the Harris Hip Score. Complications to date have been surgeon related, with three femoral components needing early revision for technical reasons. This has not affected the bearing surfaces. Radiological and clinical assessment shows no difference between the different bearing surface groups. Post operative whole
There have been no large comparative studies of the blood levels of metal ions after implantation of commercially available hip resurfacing devices which have taken into account the effects of femoral size and inclination and anteversion of the acetabular component. We present the results in 90 patients with unilateral articular surface replacement (ASR) hip resurfacings (mean time to blood sampling 26 months) and 70 patients with unilateral Birmingham Hip Resurfacing (BHR) implants (mean time 47 months). The whole blood and serum chromium (Cr) and cobalt (Co) concentrations were inversely related to the size of the femoral component in both groups (p <
0.05). Cr and Co were more strongly influenced by the position of the acetabular component in the case of the ASR, with an increase in metal ions observed at inclinations >
45° and anteversion angles of <
10° and >
20°. These levels were only increased in the BHR group when the acetabular component was implanted with an inclination >
55°. A significant relationship was identified between the anteversion of the BHR acetabular component and the levels of Cr and Co (p <
0.05 for Co), with an increase observed at anteversion angles <
10° and >
20°. The median whole blood and serum Cr concentrations of the male ASR patients were significantly lower than those of the BHR men (p <
0.001). This indicates that reduced diametral clearance may equate to a reduction in metal ion concentrations in larger joints with satisfactory orientation of the acetabular component.
Introduction: The purpose of this retrospective study is to compare long-term whole
Metal-metal surface replacement (MoMSRA) continues to be used in young women. Systemic metal ion release and its effects cause concern. Do metal ions crossing the placenta in pregnant women have potential mutagenic effects? The hypothesis is that metal ions pass freely through the placenta and there is no difference in maternal and cord metal levels. This is a controlled cross-sectional study of women with MoMSRA. (n = 25, 3 bilateral, mean age 32 years, time from implantation to delivery 60 months). The control group consisted of 24 subjects, mean age 31 years, with no metallic implant and not receiving cobalt/chromium supplements. No patient was known to have renal failure. Whole blood specimens were obtained before delivery and before any infusion or transfusion, and cord blood specimens immediately after delivery.Introduction
Methods
The combination of a ceramic head articulating against a metal acetabular liner (CoM) has shown reduced metal ion levels compared with a metal-on-metal bearing (MoM) in hip simulator studies. A randomized prospective clinical trial was undertaken using CoM and MoM bearings in an otherwise identical total hip procedure. The initial clinical results were encouraging. This report comprises a further review of metal ion data. Patients received identical components with the exception of the bearing surface material but all were 28mm diameter. All components were supplied by DePuy International Ltd. Patients were assessed pre-operatively, 3m, 12m and >
24m (median 32m). Whole blood samples were collected at regular follow-ups, frozen and analysed in batches using high resolution Inductively Coupled Plasma – Mass Spectrometry (ICP-MS). All recruited patients are included irrespective of outcome. However some patients failed to attend specific follow-ups and some contaminated samples had to be discarded. Statistical significance was analyzed using a non-parametric comparison (Mann-Whitney test). After 3m and 12m implantation there were between 21 and 24 patients available for analysis in both the CoM and MoM cohort and after >
24m point 10 and 9 respectively. There were four outliers (either Cr or Co >
10ug/l) in both the CoM and MoM groups. In common with previous studies (with the exception of two marginal outliers), these were related to component position. They were implanted with either a cup abduction angle of >
55°, an anteversion angle of >
30° or both. Other studies with the same design of component have reported no significant outliers. The median Cr and the Co levels are lower with the CoM bearing compared with the MoM at all measurements points following implantation. The median background (pre-operative) levels for the combined CoM and MoM group were Cr: 0.22ug/l and Co: 0.49ug/l. These were significantly different (p=0.006). In the CoM group, the median 12m Cr and Co values were 0.43ug/l and 0.72ug/l respectively. The comparable values for MoM are 0.68ug/l and 0.83ug/l. Increases in metal ion levels from pre-operative levels are used as the primary ion level outcome in this study because the background level will comprise of the order of 30–50% of the overall value. The increase in Cr for CoM and MoM from pre-op levels to 12m significantly different for Cr (p=0.015). It has a lower significance for combined metal ion levels (p=0.029). This difference in not significant for Co (p=0.195). In agreement with predictions from hip simulator studies, CoM bearings in this study produced lower levels of metal ions than comparable MoM bearings at all time points. However the difference is less than that predicted in the laboratory and is much more pronounced with Cr than with Co.
Orthopaedic cobalt chromium particles and ions can induce indirect DNA damage and chromosome aberrations in human cells on the other side of a cellular barrier in tissue culture. This occurs by intercellular signalling across the barrier. We now show that the threshold for this effect depends on the metal form and the particle composition. Ionic cobalt and chromium induced single strand breaks at concentrations equivalent to those found in the blood of patients with well functioning metal on metal hip prostheses. However, they only caused double strand breaks if the chromium was present as chromium (VI), and did not induce chromosome aberrations. Nanoparticles of cobalt chromium alloy caused DNA double strand breaks and chromosome aberrations, of which the majority were tetraploidy. Ceramic nanoparticles induced only single strand breaks and/or alkaline labile sites when indirectly exposed to human fibroblasts. The assessment of reproductive risk from maternal exposure to biomaterials, especially those liberated by orthopaedic implants, is not yet possible with epidemiology. Whilst the barrier model used here differs from the in vivo situation in several respects, it may be useful as a framework to evaluate biomaterial induced damage across physiological barriers.
A two sample t-test demonstrated cobalt and chromium ion levels were significantly higher in patients with abnormalities on USS (p=0.038, p=0.05 respectively), patients with normal USS were more likely to have a retroverted femoral component (p=0.01).
We have previously described the relationship between wear rates of MOM components and soft tissue necrosis. In this study we investigated the link between wear rates, metal ion concentrations and osteolysis. All unilateral patients who underwent revision of hip resurfacings at our centre were included. Retrieved components were analysed using a coordinate measuring machine to determine total volumetric material loss and rates of wear. Given the accuracy of the wear calculations (which we have previously published), wear rates were considered “abnormal” if ≥3mm3/yr. ROC curves were constructed to determine a Co concentration which would be clinically useful to detect abnormal wear. During revision, the presence/absence of osteolysis was documented.Background
Methods
In metal-on-polyethylene (MoP) total hip arthroplasty (THA), large metal femoral heads have been used to increase stability and reduce the risk of dislocation. The increased size of the femoral head can, however, lead to increased taper corrosion, with the release of metal ions and adverse reactions. The aim of this study was to investigate the relationship between the size of the femoral head and the levels of metal ions in the blood in these patients. A total of 96 patients were enrolled at two centres and randomized to undergo MoP THA using either a 32 mm metal head or a femoral head of between 36 mm and 44 mm in size, being the largest possible to fit the thinnest available polyethylene insert. The levels of metal ions and patient-reported outcome measures (Oxford Hip Score, University of California, Los Angeles Activity Scale) were recorded at two and five years postoperatively.Aims
Methods
In metal-on-polyethylene (MoP) THA large femoral metal heads are designed to increase stability and to reduce dislocation risk. The increased head size could lead to increased taper corrosion with the release of metal ions and adverse reactions. Using blood ion measurements, we aimed to investigate the association between femoral head size and metal-ion release after MoP THA. 96 patients were enrolled at two centers and randomized to receive either a 32-mm metal head or a 36–44 mm metal head (the largest possible fitting the thinnest available polyethylene insert).
Aims. To determine whether there is any association between glomerular
filtration rate (GFR) and blood cobalt (Co) and chromium (Cr) levels
in patients with metal-on-metal (MoM) hip arthroplasty. Patients and Methods. We identified 179 patients with a unilateral 36 mm diameter head
as part of a stemmed Summit-Pinnacle MoM hip arthroplasty. GFR was
calculated using the Modification of Diet in Renal Disease formula. Results. Normal renal function (GFR ≥ 90 ml/min/1.73 m. 2. ) was
seen in 74 patients. Mild renal insufficiency (GFR 60 to 89 ml/min/1.73
m. 2. ) was seen in 90 patients and moderate renal insufficiency
(GFR 30 to 59 ml/min/1.73 m. 2. ) in 15. There was no statistical
difference in Co and Cr levels between patients with normal renal
function and those with mild or moderate renal insufficiency. No
correlation was seen between creatinine and
Aims. The purpose of this study was to compare two different types
of metal-on-metal (MoM) bearing for total hip arthroplasty (THA):
one with a large femoral head (38 mm to 52 mm) and the other with
a conventional femoral head (28 mm or 32 mm). We compared clinical
outcome,
Recent studies have demonstrated that implant-specific
This study compared component wear rates and pre-revision
Aims. To find out if there is an inverse association between estimated glomerular filtration rate (eGFR) and whole blood cobalt (Co) and chromium (Cr) levels in patients with metal-on-metal (MoM) hip arthroplasties and renal insufficiency, suggesting that renal insufficiency could cause accumulation of Co and Cr in blood. Methods. Out of 2,520 patients with 3,013 MoM hip arthroplasties, we identified 1,244 patients with whole blood Co, Cr, and creatinine measured within no more than a one-year interval. We analyzed the correlation of
Metal on metal total hip arthroplasty (MoM THA) provides the potential improvement in articular wear. However, several adverse events including pseudotumor had been reported. Magnetic resonance imaging (MRI) was considered to be the proposal tool for detection of pseudotumor after MoM THA. In this study, we performed the screening of pseudotumor after MoM THA using the MRI. We studied 43 patients with M2a Magnum® (Biomet) and 34 patients with M2a Taper® (Biomet) of MoM THA from December 2009 to December 2011 with follow-up of 2.5 years (2.0–4.0 years) after surgery. MRI assessments were performed at a mean of 2.1 years postoperatively. Pseudotumor findings were graded using Anderson classification (Skeletal Radiol, 2011: 40; 303). Age, sex, height, weight, Harris Hip Score, EQ5D satisfaction score, UCLA activity score, and
Introduction. Many worldwide regulatory authorities recommend regular surveillance of metal-on-metal hip arthroplasty patients given high failure rates. However concerns have been raised about whether such regular surveillance, which includes asymptomatic patients, is evidence-based and cost-effective. We determined: (1) the cost of implementing the 2015 MHRA surveillance in “at-risk” Birmingham Hip Resurfacing (BHR) patients, and (2) how many asymptomatic hips with adverse reactions to metal debris (ARMD) would have been missed if patients were not recalled. Methods. All BHR patients subject to the 2015 MHRA recall (all females, and males with head sizes 46mm or below, regardless of symptoms) at one specialist centre were invited for review (707 hips). All patients were investigated (Oxford Hip Score, radiographs,
Aims. Dual mobility (DM) implants have been shown to reduce the dislocation rate after total hip arthroplasty (THA), but there remain concerns about the use of cobalt chrome liners inserted into titanium shells. The aim of this study was to assess the clinical outcomes, metal ion levels, and periprosthetic femoral bone mineral density (BMD) at mid-term follow-up in young, active patients receiving a modular DM THA. Methods. This was a prospective study involving patients aged < 65 years, with a BMI of < 35 kg/m. 2. , and University of California, Los Angeles activity score of > 6 who underwent primary THA with a modular cobalt chrome acetabular liner, highly cross-linked polyethylene mobile bearing, and a cementless titanium femoral stem. Patient-reported outcome measures, whole
Introduction. Uncertainties in the management of patients with MOM hip implants continue to be a problem for all surgeons. Guidelines vary and do not fully define or quantify thresholds. We aimed to assess the differences in decision-making amongst an international community of six specialist orthopaedic institutions. Methods. Five international tertiary referral orthopaedic units (one UK, two USA, and two European) were invited to participate. Each unit organised an MDT panel consisting of 2 or more hip surgeons and a musculoskeletal radiologist. All units discussed the same 10 patients. A full clinical dataset was provided including blood test and all imaging. Differences in the interpretation of findings, management decision and rationale for decisions were compared between institutions. Results. Asymptomatic patients with metal ions below 7ppb and intra-articular synovitis were collectively treated with monitoring and repeat ion measurement. Symptomatic patients with similar findings were recommended revision surgery by all units. Raised metal ions and a cystic pseudotumour on imaging that is palpable clinically was also consistently recommended revision surgery. Moderate symptoms (OHS 30), 2B pseudotumour, and moderate metal ions (cobalt 5.5ppb) were seen as an indication for revision in 5 units, however the reverse is seen if the patient had several co-morbidities. Further to this, rising
Introduction. We investigated whether
Introduction. Studies of metal-on-metal (MoM) hip resurfacing arthroplasty (HRA) have reported high complication and failure rates due to elevated metal ion levels. These rates were shown to be especially high for the Articular Surface Replacement (ASR) HRA, possibly due to its unique design. Associations between metal ion concentrations and various biological and mechanical factors have been reported. Component positioning as measured by acetabular inclination has been shown to be of especially strong consequence in metal ion production in ASR HRA patients, but few studies have evaluated acetabular anteversion as an independent variable. The primary objective of this study was to evaluate the associations between component orientation, quantified by acetabular inclination and anteversion, and
Circulating cobalt and chromium from metal-on-metal implants cause rare but fatal autopsy-diagnosed cardiotoxicity. Concern exists that milder cardiotoxicity may be common and under-recognized. Unacceptably high failure rates of metal-on-metal hip implants have prompted regulatory authorities to issue worldwide safety alerts. Despite this, approximately 1 million patients continue to live with metal-on-metal implants, putting them at risk of systemic toxicity. Although blood cobalt and chromium levels are easily measured and track local toxicity, no non-invasive tests for organ deposition exist. We recently demonstrated the utilisation of a T2* protocol (cardiovascular MRI) to detect cobalt and chromium deposition within the liver of a patient with elevated blood cobalt levels (confirmed by liver biopsy tissue analysis and X-ray fluorescence spectroscopy). We sought to detect and constrain the correlation between
Abstract. Introduction. Several studies have reported significant cobalt(Co) and chromium(Cr) elevations in the blood of patients with total-knee-replacements (TKRs), and histological signs of metal sensitivity have been reported in up to 44% of patients undergoing revision of their TKRs. We carried out this investigation to determine the source and quantity of metal release in TKRs. Methodology. We identified all TKRs with polished CoCr trays (N=59) [Vanguard=29, Attune=4 and PFC=26]. These were analysed using peer-reviewed [coordinate-measuring-machine (CMM)] methodology to measure the volumetric wear of the polyethylene (PE) bearing surfaces and trays. The trays were analysed using 2D-profilometry (surface roughness-Ra) and 4D-microscopy. Histological and
The aim of this study was to investigate the
possible benefit of large-head metal-on-metal bearing on a stem
for primary hip replacement compared with a 28 mm diameter conventional
metal-on-polyethylene bearing in a prospective randomised controlled
trial. We investigated cemented stem behaviour between these two
different bearings using Einzel-Bild-Röntgen-Analyse, clinical and
patient reported measures (Harris hip score, Western Ontario and
McMaster Universities osteoarthritis index, Short Form-36 and satisfaction)
and whole
Introduction. Failure rates of Metal-on-Metal (MoM) ASR XL hip implants have been unacceptably high compared with other bearing surfaces, so patients must be monitored over the time checking for disorders in clinical condition, blood tests or in diagnostic imaging. Objectives. We have carried out a continuing prospective investigation to evaluate the relationship between
Aims. The aim of this study was to evaluate
Whole
Whole
Purpose: Whole
Aims. To analyze the short-term outcome of two types of total wrist arthroplasty (TWA) in terms of wrist function, migration, and periprosthetic bone behaviour. Methods. A total of 40 patients suffering from non-rheumatoid wrist arthritis were enrolled in a randomized controlled trial comparing the ReMotion and Motec TWAs. Patient-rated and functional outcomes, radiological changes,
Introduction:. We present the mid-term results of our consecutive series of 155 hips treated with ASR XL Acetabular System (ASR-XL) for large-diameter metal-on-metal total hip arthroplasty and with DePuy ASR Hip Resurfacing System (ASR) for hip resurfacing. Methods:. 114 ASR-XL and 41 ASR were implanted between 2004 and 2008 in 145 patients (69 men and 76 women) with a mean age of 57 years. Twenty-one patients (23 hips) resulted lost to follow-up. All patients were recalled and monitored periodically with clinical, hematological and radiological evaluation. Average follow-up of the 155 hips was 72 months (1 to 104). The mean follow-up, excluding revised patients and those lost to follow-up, was up to 89 months. Results:. At latest follow-up we had revised 54 of 155 hips (35%) with complete removal of ASR device. Revision involved 15 hips with ASR (36.5% within ASR group) and 39 hips with ASR-XL (34.2% within ASR-XL group). Main reasons for revision were aseptic loosening in 24 hips (44%), pain or pain associated with elevation of
Purpose. Elevated
Metal-on-metal (MOM) hip arthroplasty has been associated with a variety of new failure modes that may be unfamiliar to surgeons who traditionally perform metal-on-polyethylene THR. These failure modes include adverse local tissue reaction to metal debris, hypersensitivity to metal debris, accelerated wear/metallosis, pseudotumours, and corrosion. A significant number of patients with metal-on-metal hip arthroplasty may present to surgeons for routine followup, concern over their implant, or frank clinical problems. A common issue with MOM hip arthroplasty that can lead to accelerated wear and failure is implant malposition. Malposition of a hard-on-hard bearing can lead to edge loading and accelerated wear at the articular surfaces, which will lead to elevation in
Aims. Modular dual mobility (DM) prostheses in which a cobalt-chromium liner is inserted into a titanium acetabular shell (vs a monoblock acetabular component) have the advantage of allowing supplementary screw fixation, but the potential for corrosion between the liner and acetabulum has raised concerns. While DM prostheses have shown improved stability in patients deemed ‘high-risk’ for dislocation undergoing total hip arthroplasty (THA), their performance in young, active patients has not been reported. This study’s purpose was to assess clinical outcomes, metal ion levels, and periprosthetic femoral bone mineral density (BMD) in young, active patients receiving a modular DM acetabulum and recently introduced titanium, proximally coated, tapered femoral stem design. Patients and Methods. This was a prospective study of patients between 18 and 65 years of age, with a body mass index (BMI) < 35 kg/m. 2. and University of California at Los Angeles (UCLA) activity score > 6, who received a modular cobalt-chromium acetabular liner, highly crosslinked polyethylene mobile bearing, and cementless titanium femoral stem for their primary THA. Patients with a history of renal disease and metal hardware elsewhere in the body were excluded. A total of 43 patients (30 male, 13 female; mean age 52.6 years (. sd. 6.5)) were enrolled. All patients had a minimum of two years’ clinical follow-up. Patient-reported outcome measures, whole
The Articular Surface Replacement (ASR) hip resurfacing arthroplasty has a failure rate of 12.0% at five years, compared with 4.3% for the Birmingham Hip Resurfacing (BHR). We analysed 66 ASR and 64 BHR explanted metal-on-metal hip replacements with the aim of understanding their mechanisms of failure. We measured the linear wear rates of the acetabular and femoral components and analysed the clinical cause of failure, pre-revision
Introduction:. The ASR™ Articular Surface Replacement and ASR™ XL Metal-on-Metal systems were recalled due to high revision rates at five years. A worldwide clinical follow-up of patients was initiated. This paper summarizes current findings in South Africa (SA) in comparison with those outside SA (OSA). Methods:. Patients were followed annually, or until revision, from 10 clinical centers worldwide. Data collected includes demographic, surgical, radiographic,
Objectives. 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. Methods. 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
Background. Post-market surveillance is necessary to ensure the safety and efficacy of newly introduced technologies and implants. The Birmingham Hip Resurfacing (Smith and Nephew, Inc., Memphis, TN) was the first hip resurfacing implant approved for use by the US FDA in May 2006. A prospective, multi-center postmarket approval study has been in progress to assess safety and efficacy of this implant. Methods. Patients meeting inclusion criteria were enrolled at five sites. Clinical evaluation and radiographs were obtained at 3 months and 1 year, and annually thereafter for a total of 10 years.
Introduction. Complication and revision rates have shown to be high for all metal-on-metal (MoM) bearings, especially for the ASR Hip System (ASR hip resurfacing arthroplasty (HRA) and ASR XL total hip arthroplasty (THA)). This prompted the global recall of the ASR Hip System in 2010. Many studies have previously explored the association between female gender and revision surgery MoM HRA implants; yet less research has been dedicated to exploring this relationship in MoM THA. The first purpose of this study was to assess the associations between gender and implant survival, as well as adverse local tissue reaction (ALTR), in patients with MoM THA. Secondly, we sought to report the differences between genders in metal ion levels and patient reported outcome measures (PROMs) in patients with MoM THA. Methods. The study population consisted of 729 ASR XL THA patients (820 hips) enrolled from September 2012 to June 2015 in a multicenter follow-up study at a mean of 6.4 (3–11) years from index surgery. The mean age at the time of index surgery was 60 (22–95) years and 338 were women (46%). All patients enrolled had complete patient and surgical demographic information,
Introduction. Little is known about variations in
We prospectively assessed the efficacy of a ceramic-on-metal
(CoM) hip bearing with uncemented acetabular and femoral components
in which cobalt–chrome acetabular liners and alumina ceramic heads
were used. The cohort comprised 94 total hip replacements (THRs) in 83 patients
(38 women and 45 men) with a mean age of 58 years (42 to 70). Minimum
follow-up was two years. All patients had pre- and post-operative
assessment using the Western Ontario and McMaster Universities osteoarthritis
index (WOMAC), Oxford hip score and Short-Form 12 scores. All showed
a statistically significant improvement from three months post-operatively
onwards (all p <
0.001). After two years whole
Introduction. Cemented stems have shown 90–100% survivorship when coupled with polyethylene acetabular component. This study aims to compare cemented stem behaviour in combination with large metal on metal (MOM) vs. metal on poly (MOP) bearings. Patients and Methods. 100 patients were recruited into a single centre RCT (we required 40 in each group for power .90 to confirm stem subsidence of >0.5mm at 2 years; p< 0.05). Recruits were randomized to MOP (28mm) or MOM femoral heads with CPCS cemented femoral stem. Assessments included X-rays (AP pelvis), Harris Hip Scores,
SUMMARY. We report a prospective study of clinical data collected pre, intra and post operation to remove both cup and head components of 118 failed, current generation metal on metal (MOM) hips. Whilst component position was important, the majority were unexplained failures and of these the majority (63%) had cup inclination angles of less than 55 degrees. Poor biocompatibility of the wear debris may explain many of the failures. BACKGROUND. Morlock et al reported a retrospective analysis of 267 MOM hips but only 34 head and cup couples (ie most were femoral neck fractures) and without data necessary to define cause of failure. The commonest cause of failure in the National Joint Registry (NJR) is unexplained. METHODS. We categorised the cause of failure, as defined by the NJR, of all MOM hips received over an 18 month period that had a full set of pre, intra and post op data. A group of 40 patients with unilateral well functioning MOM hips was used for comparison. RESULTS. In the retrieval group, the median age was 61 years (25 to 87) and there were 80 females and 38 males. The median time between primary and revision operation was 35 months (4 to 121). Femoral head size was <50mm in 89 and >=50mm in 29. The causes of failure were: unexplained in 75; aseptic loosening (acetabular) in 12; aseptic loosening (femoral) in 7; dislocation/subluxation in 1; infection in 11; periprosthetic femoral fracture in 2; malalignment in 6; size mismatch in 3; other in 1. 47 (63%) of unexplained failures had cup inclination angles of less than 55 degrees. The unexplained failures had increased
This study reports on ceramic-on-metal (CoM) bearings in total hip replacement. Whole
We present the mid-term results of our consecutive series of 155 hips treated with ASR extra-large (XL) Acetabular System (ASR XL) and with ASR Hip Resurfacing System (ASR). We reviewed the clinical records of patients with implanted ASR or ASR XL. All patients were recalled and invited to come to our hospital for a periodic clinical, hematological and radiological evaluation.114 ASR XL and 41 ASR were implanted between 2004 and 2008 in 145 patients (69 men and 76 women) with a mean age of 57 years. 21 patients (23 hips) were lost from follow-up. Average follow-up was 76 months (50 to 91). Up now 42 ASR implants have been revised (27.0%): revision involved 9 hips on 41 treated with resurfacing (21.9%) and 33 hips on 114 treated with XL total hip arthroplasty (28.9%). Main reasons for revision were aseptic loosening with or without metallosis in 23 hips (56%), infection in 3 hips (7%), recurrent dislocation in 1 hip (2%), periprosthetic fractures in 1 hip (2%), elevation of
Introduction. Metal-on-metal (MoM) hip resurfacing arthroplasty is a popular choice for young and active patients. However, there are concerns recently regarding soft tissue masses or pseudotumours. The appearance of these complications is thought to be related
This prospective study evaluates the outcome of a new metal -on-metal total hip replacement in a younger group of patients. Fifty-five primary all-metal total hip replacements (THR) were evaluated prospectively at a follow-up of 2.8–5.5 years. Patients were selected according to age and activity levels. The mean age was 58 years (41–69). 33 males and 22 females were included in the study. Surgery was carried out for osteoarthritis in 52 patients and for non-union fractured femoral neck, ankylosing spondilitis and post slipped upper femoral epiphysis in the three remaining patients. A single surgeon (the senior author) through the posterior approach carried out the surgery. All patients received the porous coated titanium shell with a Morse taper cobalt chrome liner and double wedge tapered polished cobalt chrome stem and modular head.
Objectives. This study aimed to characterise and qualitatively grade the severity of the corrosion particles released into the hip joint following taper corrosion. Methods. The 26 cases examined were CoC/ABG Modular (n = 13) and ASR/SROM (n = 13).
Fifty five primary Ultima® hybrid all-metal (Johnson &
Johnson Professional DePuy) total hip replacements (THR) were evaluated prospectively at a mean follow up of 24 months. Patients were selected according to age and activity levels. The mean age at surgery was 58 years (41–69 years). 33 males and 22 females were included in the study. Surgery was carried out for osteoarthritis in 52 patients and for non-union fractured neck of femur, ankylosing spondilitis and post slipped upper femoral epiphysis in the three remaining patients. A single surgeon (the senior author) through the posterior approach carried out surgery. All patients received the Ultima® porous coated titanium shell with a morse taper cobalt chrome liner and double wedge taper polished stem and modular head.
An increase in metal ion levels is seen after implantation of all MoM hip prosthesis due to release from the surface directly, more so during articulation and corrosion of the bearing surfaces. The bearing surfaces in MoM prosthesis consist of cobalt, chromium and molybdenum. Several case-reports of cobalt toxicity due to a MoM prosthesis have been published in the last decade. Cobalt intoxication may lead to a variety of symptoms: neuro-ocular toxicity (tinnitus, vertigo, deafness, blindness, convulsions, headaches and peripheral neuropathy), cardiotoxicity and thyroid toxicity. Nausea, anorexia and unexplained weight loss have been described. Systemic effects from metal ions even with well functioning implants or with ion concentrations lower than those associated with known adverse effects may exist and warrant investigation. The aim of this study is to investigate self-reported systemic complaints in association with cobalt ion concentrations in patients with any type of MoM hip prosthesis. A cohort study was conducted. Patients with both unilateral and bilateral, resurfacing and large head metal on metal total hip arthroplasties were included for the current study.
We carried out metal artefact-reduction MRI, three-dimensional CT measurement of the position of the component and inductively-coupled plasma mass spectrometry analysis of cobalt and chromium levels in whole blood on 26 patients with unexplained pain following metal-on-metal resurfacing arthroplasty. MRI showed periprosthetic lesions around 16 hips, with 14 collections of fluid and two soft-tissue masses. The lesions were seen in both men and women and in symptomatic and asymptomatic hips. Using three-dimensional CT, the median inclination of the acetabular component was found to be 55° and its positioning was outside the Lewinnek safe zone in 13 of 16 cases. Using inductively-coupled plasma mass spectrometry, the levels of
Introduction. It is well-known that wear debris generated by metal-on-metal hip replacements leads to aseptic loosening. This process starts in the local tissue where an inflammatory reaction is induced, followed by an periprosthetic osteolysis. MOM bearings generate particles as well as ions. The influence of both in human bodies is still the subject of debate. For instance hypersensitivity and high
To assess clinical outcomes, metal ion levels, and periprosthetic femoral bone mineral density (BMD) in young, active patients receiving a modular dual mobility acetabulum and recently introduced titanium, proximally coated, tapered femoral stem design. This was a prospective study of patients 65 years of age, with a BMI 35 kg/m. 2. , and UCLA activity score > 6 who received a modular cobalt chrome acetabular liner, highly cross-linked polyethylene mobile bearing, and cementless titanium femoral stem for their primary THA. Patients with a history of renal disease and metal hardware elsewhere in the body were excluded. All patients had a minimum of 2-year clinical follow-up. Patient reported outcome measures, whole
Pain following total hip arthroplasty is a relatively rare event. Several series place the incidence of some degree of pain post THA at approximately 5%. A systematic approach to determining etiology will direct treatment. Hip pain can be categorised as:. Extrinsic to the Hip. –. Spine +/− radiculopathy. –. Vascular disease. –. Metabolic (Paget's). –. Malignancy. Intrinsic to the Hip. Intracapsular/Implant. Loosening. Sepsis. Prosthetic failure. Osteolysis. Instability. Thigh pain. Stem tip pain. Hypersensitivity/ALVAL. Extracapsular. Iliopsoas tendonitis. Snapping Hip. Trochanter problems (bursitis). Heterotopic ossification. A full history and appropriate physical exam will direct the clinician. The use of routine radiographs, blood tests, and special tests (i.e.,
Introduction. The Birmingham Hip Resurfacing (Smith & Nephew London, UK) is the most popular hip resurfacing (HR) in the UK. However, it is now subject to two Medical Device Alerts (MDA) from the Medicines and Healthcare products Regulatory Agency (MHRA). Patients/Materials & Methods. A cross-sectional survey of primary metal-on-metal hip procedures recorded on the National Joint Registry for England, Wales and Northern Ireland (NJR) until 5. th. November 2013 was performed. Cost-analysis was based on an algorithm for surveillance of HR at a tertiary referral centre and followed previous MHRA guidance. NIHR NHS Treatment costs were used. The local protocol encompassed: patient outcome scoring (Oxford hip score),
Introduction. The impact of pseudotumours associated with metal-on-metal hip resurfacings (MoMHRs) within the second decade is unknown. We investigated: (1) the incidence and risk factors for all-cause and pseudotumour revision following MoMHR at 15-years follow-up, and (2) whether risk factors were gender specific. Patients and methods. This single-centre prospective cohort study included 1429 MoMHRs (1216 patients; 40% female) implanted between 1999–2009. All patients were contacted in 2010 and 2012 as per national recommendations. Patients with hip problems and/or suboptimal Oxford Hip Scores (<41/48) underwent cross-sectional imaging and
Introduction:. Whole
Introduction. When following patients with metal-on-metal (MoM) hip replacements, current evidence suggests that orthopaedic surgeons should avoid reliance on any single investigative tool. In 2014, guidelines for stratifying patients with MoM hip replacement into groups of low, medium, and high risk of failure based on multiple criteria were published. However, such risk stratification guidelines can be difficult to interpret due to the numerous risk factors related to MoM hip replacements. This is especially true for patients with various (high and low) risk levels for different criteria within the guidelines. The first purpose of this study was to assess if a scoring system can be applied to the current MoM guidelines. The second purpose was to test, using this scoring system, how the contemporary guidelines would classify a cohort of patients with a recalled MoM hip replacement system. Methods. The study population consisted of 1301 patients (1434 hips) enrolled from September 2012 to June 2015 in a multicenter follow-up study of a recalled MoM hip replacement system at a mean of 6.2 (range 2.4 – 11.2) years from index surgery. Eleven required scoring criteria were determined based on existing follow-up algorithm recommendations and consisted of patient factors, symptoms, clinical status, implant type, metal ion levels, and radiographic imaging results. Criteria considered ‘low’ risk were given 1 point, 2 points for ‘moderate’ risk, and 3 points for the ‘high’ risk group. Forward stepwise logistic regression was conducted to determine the minimum set of predictive variables for risk of revision and assign variable weights. The MoM risk score for each hip was then created by averaging the weighted values of each predictive variable. Results. Only two of the proposed eleven criteria were found to be significant predictors of revision in our logistic regression model; clinical status (as measured by the Harris Hip Score) and
Introduction. This study aimed to: (1) compare published follow-up guidelines for metal-on-metal (MoM) hip patients and analyse protocols in relation to current evidence, and (2) assess the financial implications of these guidelines. Methods. Follow-up guidance for MoM hips from five national authorities (MHRA in the UK; EFORT; United States FDA; Therapeutic Goods Administration of Australia; Health Canada) were contrasted and critically appraised. Using National Joint Registry (NJR) data (67,363 MoM hips implanted) the cost of annual surveillance for all MoM hips recorded in the NJR was calculated for each protocol. Results. Significant differences existed between recommended guidance, with protocols not reflecting the best available evidence. These include not stratifying patients according to implant type (total hip replacement (THR) or hip resurfacing (HR)) or adverse reaction to metal debris (ARMD) risk factors, using symptoms to decide patient follow-up, and using suboptimal
Introduction. Edge loading is a common wear mechanism in Metal-on-Metal (MOM) hip resurfacing and is associated with higher wear rates and the incidence of pseudotumour. The purpose of this study was to develop a method to investigate the contributions of patient, surgical and implant design variables on the risk of edge loading. Method. We created a mathematical model to calculate the distance from the head-cup contact patch to the rim of the cup and used this to investigate the effect of component position, specific design features and patient activity on the risk of edge loading. We then used this method to calculate the contact patch to rim distance (CPRD) for 160 patients having undergone revision of their MOM hip resurfacing in order to identify any possible associations. Results. We identified several variables that reduce the CPRD and increase the risk of edge loading, including; increased cup anteversion and inclination, activities involving increased hip flexion, reduced clearance, reduced hip diameter and reduced cup arc angle. We also determined the threshold cup orientation for edge loading for five resurfacing designs (Figure 1). In patients with failed MOM hip resurfacings, there was a significant correlation between CPRD and both component wear rates (Figure 2) and
Introduction: Local problems of metal on metal (MOM) hip arthroplasty such as pseudotumours, neck thinning and osteolysis maybe related to concentrations of cobalt and chromium ions in the synovial fluid. There is little reported on these values. Our aim was to determine the range of metal ion levels in synovial fluid, and to investigate the relationship between these samples and simultaneous blood samples. Methods: Synovial fluid and whole blood samples were taken from 30 consecutive patients at the time of revision surgery for a painful MOM hip. Aspirated fluid was not visibly contaminated with blood. Impants were in situ for a mean period of 31 months. All had normal renal function. Samples were analysed using ICP mass spectrometry and compared with 10 samples from patients without implants. Results: The mean (and range) of synovial fluid metal ion levels were 1965 ug/l (30 to 13618) and 6265 ug/l (11 to 81630) for Cobalt and Chromium respectively. There was a good correlation between synovial and blood levels for both cobalt (R=0.65, p = 0.0001) and chromium (R = 0.59, p = 0.006). Discussion and Conclusion: Metal ions in synovial fluid from MOM hips are generated from wear of the bearing surfaces, the correlation with
Purpose. Our primary purpose was to study the rate of occurrence and the natural course of pseudotumors in patients who had not required a revision procedure. Our secondary purpose was to see if there is a relationship between serum metal ion analysis and clinical symptoms with metal-on-metal (MOM) hip arthroplasty. Patients and Methods. We used repeated metal artifact reduction sequence (MARS) magnetic resonance imaging (MRI) to screen 17 unrevised hips (mean patient age 63.0 years, 43 to 83 years) with pseudotumors and 26 hips (mean patient age 63.2 years, 47 to 83 years) without pseudotumors. Patients with 17 MOM, 17 ceramic-on-polyethylene (COP) and 7 ceramic on ceramic (COC) who had undergone repeated MARS MRI were evaluated with or without any symptoms. We utilized MARS MRI to score the type of pseudotumors using the Hart method. The mean post-operative time to the first MARS MRI scan was 30.0 months (8 to 96), and the time between the first and the second MARS MRI scan was eleven months (6 to 12). Serum Cr and Co ion measurements were undertaken at the time of both MRIs and analyzed only after MOM total hip arthroplasty. Results. The rate of occurrence of pseudotumors was 47.5% with MOM, 33.0% with COP, and 25.0% with COC. There was a significant difference in number of abnormalities between MOM and COP and COC bearing. At the second MRI scan, the grade of severity of pseudotumors had not changed in 40 hips. Two new asymptomatic pseudotumors (MOM:1 case, COP:1 case) were detected and one pseudotumor was downgraded. In 17 patients with pseudotumors, two cases (11.7%) were symptomatic and in 26 patients without pseudotumors, 4 cases (15.3%) were symptomatic, with no significance between the two groups. In 17 patients with MOM cases, only two cases with pseudotumors were symptomatic, and both cases showed elevated
Monitoring the performance of hip replacements post-operatively is tedious and costly, necessitating radiological examinations as well as other specialized examinations such as whole
Metal on Metal hip resurfacing (MoM HR) can be an effective operation for the young arthritic hip population. However, errors in cup orientation have been associated with increased wear, circulating
Introduction. The articulating surfaces of a new metal-on-metal (MoM) hip prosthesis system were modified with the ceramic Titanium-Niobium-Nitride (TiNbN) by Physical Vapor Deposition (PVD). The purpose of the study was to investigate whether the elevation of the ion levels of chromium and cobalt, normally seen in the blood of patients after MoM hip arthroplasty, can be prevented by ceramic engineering of the articulating metal surfaces. Materials and methods. the ACCIS components (manufactured by Implantcast GmbH, Buxtehude, Germany from casted hi-carbon Co-Cr-Mo alloy) are heat treated, polished and micro-surface finished. Then TiNbN ceramic is integrated into the metal surfaces by PVD. 200 ACCIS resurfacing hip prostheses were implanted in three centres: Morriston Hospital, Swansea and Neville Hall Hospital, Abergavenny in the UK and Arthro Clinic, Hamburg, Germany. Blood samples of 60 randomly selected patients were analysed before surgery and at intervals of 3, 6, 12 and 24 months after surgery. Independent trace metal measurements were performed at the Universitätsklinikum Carl Gustav Carus Dresden, Germany. Results. the median chromium concentrations after 2 years were 0.94 (0.25-3.6) and the median cobalt concentrations after 2 years were 1.04 (0.07-2.36) μ gr/L. The average chromium concentration after 2 years was 1.073 and the average cobalt concentration after 2 years was 1.095 μ gr/L. None of the patients at any moment after operation showed an obvious increase of Cr and Co ions in the
Introduction. Patients presenting with osteoarthritis as late sequelae following pediatric hip trauma have few options aside from standard Total Hip Replacement (THR). For younger more active patients, Hip Resurfacing Arthroplasty (HRA) can be offered as an alternative. HRA has been performed in the United States over the past decade and allows increased bone preservation, decreased hip dislocation rates versus THR, and potential to return to full activities. Patients presenting with end-stage hip arthritis as following prior pediatric trauma or disease often have altered hip morphology making HRA more complicated. Often Legg-Calve-Perthes (LCP) patients present with short, wide femoral necks, and femoral head distortion including coxa magna or coxa plana. There often can be acetabular dysplasia in conjunction with the proximal femoral abnormalities. Slipped Capital Femoral Epiphysis (SCFE) patients have an alteration of the femoral neck and head alignment, which can make reshaping the femoral head difficult. In particular, the femoral head is rotated medially and posteriorly, reducing the anterior and lateral offset. We present a cohort of 20 patients, with history of a childhood hip disorder (SCFE or LCP), who underwent HRA to treat end-stage arthritis. Fifty percent had prior pediatric surgical intervention at an average age of 11. Method. After Institutional Review Board approval, data was reviewed retrospectively on patients with pediatric hip diseases of SCFE and LCP who underwent HRA using the Birmingham Hip Resurfacing (BHR) by a single orthopaedic surgeon at a teaching institution. Harris Hip Scores (HHS), plain radiographs and
This report documents the clinical and histological findings, the operative management and the explant analyses of patients with early aseptic failure of large metal-on-metal (MonM) bearing joints. Three hundred and fifty patients have been implanted with the ASR bearing surface (resurfacing or a modular THR) by a single surgeon at an independent centre since 2004. Six patients (all female) have been revised secondary to aseptic failure. All complained of severe groin pain exacerbated by straight leg raise and routine investigations were unable to establish a cause. Large amounts of sterile, highly viscous green fluid were aspirated from the hip joints in each case. Gross swelling of the pseudocapsule and a similar green fluid surrounding the implants were found at revision surgery. Histological examination of periprosthetic tissue samples showed changes consistent with ALVAL/metallosis, and analysis of the fluid revealed dense numbers of inflammatory cells. Symptoms in patients revised to ceramic-on-ceramic bearings improved post operatively. This was not the case with those reimplanted with MoM joints. Data from a subset of 76 patients (all unilateral resurfacings) showed that malaligned cups (anteverted >
20° +/− inclination angle >
45°) were associated with significantly higher whole
Metal ion concentrations following metal on metal hip resurfacing arthroplasty remain a concern. Variables associated with increased metal ion concentrations need to be established. This study provides metal ion data from a consecutive cohort of the first 76 patients implanted with a fourth generation hip resurfacing prosthesis. All patients agreed to post-operative
In a cross sectional cohort study three different metal on metal total hip systems were assessed. Two monoblock acetabular designs; the Durom socket (Zimmer, Warsaw, In) and the Birmingham socket (Smith and Nephew, Memphis, TN), and one modular metal on metal total hip system (Pinnacle, Depuy Orthopaedics, Warsaw, In) in patients who have received these implants in the our region. 56 patients were recruited in total. All patients were assessed clinically, radiologically and biochemically. Whole blood Cobalt, Chromium and titanium levels were tested. The median head size used in the Birmingham group was 52mm (Range 44mm to 56mm), and in the Durom group, 48mm (Range 42 to 54mm). The median head size used in the modular Pinnacle group was 40mm (Range 36–44mm). The
Introduction: We have previously shown an association between whole blood metal particles from unilateral metal on metal (MOM) hip resurfacing and reduced CD8+ T cells (JBJS Br April 2006). There are no reported clinical effects of these findings. Certain patients maybe at high risk of developing clinical effects; one such group is patients with bilateral hip resurfacings. There are no published studies of bilateral hip resurfacings. Our aim was to investigate the association between whole
The aim of this study is to investigate whether MoM implants result in more chromosome aberrations and increased
There has been much discussion and controversy in the media recently regarding metal toxicity following large head metal on metal (MoM) total hip replacement (THR). Patients have been reported as having hugely elevated levels of metal ions with, at times, devastating systemic, neurolgical and/or orthopaedic sequelae. However, no direct correlation between metal ion level and severity of metallosis has yet been defined. Normative levels of metal ions in well functioning, non Cobalt-Chrome hips have also not been defined to date. The Exeter total hip replacement contains no Cobalt-Chrome (Co-Cr) as it is made entirely from stainless steel. However, small levels of these metals may be present in the modular head of the prosthesis, and their effect on metal ion levels in the well functioning patient has not been investigated. We proposed to define the “normal” levels of metal ions detected by blood test in 20 well functioning patients at a minimum 1 year post primary Exeter total hip replacement, where the patient had had only one joint replaced. Presently, accepted normal levels of blood Chromium are 10–100 nmol/L and plasma Cobalt are 0–20 nmol/L. The UK Modern Humanities Research Association (MHRA) has suggested that levels of either Cobalt or Chromium above 7 ppb (equivalent to 135 nmol/L for Chromium and 120 nmol/L for Cobalt) may be significant. Below this level it is indicated that significant soft tissue reaction and tissue damage is less likely and the risk of implant failure is reduced. Hips were a mixture of cemented and hybrid procedures performed by two experienced orthopaedic consultants. Seventy percent were female, with a mixture of head sizes used. In our cohort, there were no cases where the blood Chromium levels were above the normal range, and in more than 70% of cases, levels were below recordable levels. There were also no cases of elevated plasma Cobalt levels, and in 35% of cases, levels were negligible. We conclude that the implantation with an Exeter total hip replacement does not lead to elevation of
Comparisons of
The aim of this study is to investigate whether Metal-on-Metal (MoM) implants result in more chromosome aberrations and increased
Background. Previous studies have suggested that the modular junction of metal on metal (MoM) total hip replacements (THR) is an important source of metallic debris. Methods. We carried out a prospective study using custom techniques to analyse one of the largest collections of failed contemporary MoM devices in the world. All explants from patients who had suffered adverse reactions to metal debris (ARMD) were included in this study. These explants included: 82 36mm THRs, and 147 resurfacing head THRs and 140 resurfacing arthroplasties from several manufactures. Volumetric wear analysis of the bearing surfaces and taper junctions was carried out using a coordinate measuring machine. The relationships between total metallic loss and metal ion concentrations and the macroscopic and histological tissue appearance of THR patients were compared to those in resurfacing patients. Mann Whitney test for non-parametric data was used to assess significant differences between groups. Results. Resurfacing explants retrieved from patients who had suffered ARMD were found to have significantly higher median rates of volumetric wear than the THRs (10.16 versus 2.25mm. 3. /yr (p < 0.001)). Total volumetric material loss from taper junctions ranged from 0.01 to 21.55mm. 3. When volumetric taper wear was combined with bearing surface wear in the THR patients this total rate of material loss was still significantly less than in the resurfacing patients 2.52 versus 10.16mm. 3. /yr (p < 0.001)). Despite this, macroscopic tissue destruction and extent of ALVAL infiltration was found to be significantly greater in the THR patients. Conclusion. Taper debris appears to more readily stimulate a destructive immune cascade than debris from primary bearing surfaces. This cascade can culminate in catastrophic tissue necrosis when
Since wear debris is recognised as a major cause of hip prosthesis loosening in the last decade, research was aimed to lower the coefficient of friction. Polyethylene revealed to be the principal source of debris so new bearing materials were introduced in the effort to increase implant longevity. In 1965 Mc Keee Farrar introduced metal on metal bearings, in 1970 Boutin ceramic on ceramic. Both of them demonstrated the capability to reduce wear debris more than 97% as compared to PE-metal coupling but have possible risks. Ceramic heads are scratch resistant but they can fracture, then they offer limited options as lenght and diameter. Metal on metal bearing couples give all the options but can determine high
Introduction: The aim of this study is to investigate whether MoM implants result in more chromosome aberrations and increased
Introduction and aim: We have previously shown an association between whole
Purpose: Tribological studies suggest that larger metal-on-metal articulations would produce less wear than smaller diameter components. The aim of the present study is to describe whole blood Chrome and Cobalt ions concentration after metal-metal total hip arthroplasty (THA) and surface replacement arthroplasty (SRA). Methods: 180 patients eligible for the study were randomized to receive uncemented 28 mm metal-metal THA or a hybrid metal-metal SRA. Whole blood samples were collected pre-operatively, at three, six months and one year post operatively. Chrome and Cobalt concentration were measured by mass spectrophotometry. Results: At one year post op, whole blood levels of the were Cr 1.8 umol/L and Co 0.6 umol/L for the SRA and Cr 1.7 umol/L and Co 0.8 umol/L for the THA group (Cr, p=0.676 and Co, p=0.08). In comparison to pre-operative levels, the post operative levels significantly incresed for all elements Cr 1.9x and Co 3.8x for the SRA; Cr 1.3x and Co 3.4x. for the SRA group, Anova regression tests showed a significant relation between component size and Cr and Co metal ions levels; the larger the component, the lower the ions levels (Cr p=0.0285 and Co p=0.0442). Conclusions: Using these specific implants, the increases whole
Introduction. Total hip prostheses which use a ceramic head within a metal liner are a relatively recent introduction. As such, survivorship rates from independent centres alongside explant analysis are rare. The early experience with this novel ceramic-on-metal (CoM) bearing couple is reported. Methods and Materials. All CoM hips implanted between 2008 and 2009 at a single hospital by a single surgeon were reviewed. Radiographs were analysed using EBRA software to determine acetabular cup inclination and anteversion angles.
Bearing diameter and acetabular component orientation have been shown to be important variables effecting
Introduction: Metal on metal hip replacement using large diameter bearings can be used as part of a hip resurfacing (HR) system or with a large diameter head total hip arthroplasty (LDH-THA). Both types of implant release metal ion, but the amount of ion released after LDH-THA has not been studied. The aim of the present study was to assess whole
Introduction. Total hip prostheses which use a ceramic head within a metal liner are a relatively recent innovation. As such, survivorship rates from independent centres alongside explant analysis are rare. The early clinical experience with this novel ceramic-on-metal (CoM) bearing couple is reported alongside explant analysis of failed devices. Methods and materials. All CoM hips implanted between 2008 and 2009 at a single hospital by a single surgeon were reviewed. Radiographs were analysed using EBRA software to determine acetabular cup inclination and anteversion angles.
Purpose. To determine whether there is a difference in the metal ion levels among three different metal-on-metal total hip systems: two monoblock large heads and one modular metal-on-metal total hip replacement system in patients who received these implants in our region. Method. A group of 56 patients were recruited that had either undergone total hip replacement (THR) with a Birmingham resurfacing socket, the Durom resurfacing socket, or a Pinnacle metal-on-metal bearing surface. All patients recruited were at least one year following their surgery in order that their ion levels had reached a steady state. We reviewed every patient clinically, radiographically as well as biochemically. Blood was obtained for cobalt (Co) and chromium (Cr) levels. Current radiographs were arranged to assess the stability and mechanics of the total hip systems. All patients signed an informed consent and completed three questionnaires, The Western Ontario and McMaster Universities (WOMAC) index, the Short Form 36 (SF36) and UCLA activity score. A Harris Hip score was completed in order to assess individual hip function. Statistical analysis was performed on the collected data to assess whether there were any other potential influence on the mean levels of Co and Cr. Results. The
Metal-on-metal hip resurfacing arthroplasty (MoMHRA) has been a popular alternative treatment for young patients with hip osteoarthritis. Despite its advantages over total hip arthroplasty, the use of MoMHRA remains controversial. Achieving the correct positioning of the prosthetic is a concern due to the difficulty and novelty of this procedure. Furthermore, it has been reported that post-operative management using 2D radiographs contains high degrees of variance leading to poor detection of prosthetic malpositioning. In order to compensate for the lack of available technology, current literature has suggested the use of
