An important contribution to our understanding of the performance of the current generation of metal-on-metal hip replacements.
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ABSTRACT:
SUBMITTER: Jacobs JJ
PROVIDER: S-EPMC3748978 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BACKGROUND: Adverse reaction to metal debris is a relatively recently described and often a silent complication of metal-on-metal (MOM) total hip replacements (THR). The Norfolk & Norwich University Hospital has been performing metal artefact reduction (MARS) MRI for 8 years in a variety of different types of MOM THR. QUESTIONS/PURPOSES: The aims of this review are to describe the experience of using MARS MRI in Norwich and to compare our experience with that published by other groups. METHODS: A MEDLINE keyword search was performed for studies including MRI in MOM THR. Relevant publications were reviewed and compared with published data from the Norfolk & Norwich University Hospital. The similarities and differences between these data were compared and possible explanations for these discussed. RESULTS: MARS MRI appears to be the most useful tool for diagnosing, staging and monitoring adverse reactions to metal debris (ARMD). There appears to be no clinically useful association between clinical and serological markers of disease and the severity of MR findings. Although severe early ARMD is associated with significant morbidity, mild disease is often stable for years. If patients with normal initial MR examinations develop ARMD, this usually occurs 7 years. A 1-year interval between MRI examinations is reasonable in asymptomatic patients. CONCLUSIONS: There is a general international consensus that ARMD is prevalent in symptomatic and asymptomatic patients with MOM THR and that while appearances vary with the type of prosthesis, there are characteristic features that make MARS MRI essential for diagnosis, staging and surveillance of the disease.
| S-EPMC3772162 | biostudies-other
Project description:ObjectiveTo assess the risk of cancer associated with modern primary metal-on-metal hip replacements.DesignPopulation based study.SettingNationwide retrospective comparative register.Participants10,728 patients who underwent metal-on-metal total hip arthroplasty and 18,235 patients who underwent conventional metal-on-polyethylene, ceramic-on-polyethylene, and ceramic-on-ceramic total hip arthroplasty (the non-metal-on-metal cohort) in the Finnish Arthroplasty Register 2001-10. Data on cancer cases up to 2010 for these cohorts were extracted from the Finnish Cancer Registry.Main outcome measuresThe relative risk of cancer was expressed as the ratio of observed to expected number of cases from the Finnish population--that is, the standardised incidence ratio. The relative risk of cancer in the metal-on-metal cohort compared with the non-metal-on-metal cohort was estimated with analyses of these ratios and Poisson regression.ResultsThe overall risk of cancer in patients with metal-on-metal hip implants was similar to that in the Finnish population (378 observed v 400 expected, standardised incidence ratio 0.95, 95% confidence interval 0.85 to 1.04). The overall risk of cancer in patients with metal-on-metal hip implants was also no higher than in patients who had received non-metal-on-metal hip implants (relative risk 0.92, 0.81 to 1.05).ConclusionsMetal-on-metal hip replacements are not associated with an increased overall risk of cancer during a mean follow-up of four years.
| S-EPMC3404595 | biostudies-literature
Project description:Background and purpose - Orthopedics and especially joint replacement surgery have had more than their fair share of unsuccessful innovations that have violated widely endorsed principles for the introduction of new surgical innovations. We aimed to investigate (1) the trends in the use of the Birmingham Hip Resurfacing (BHR), the ASR hip resurfacing (ASR HRA) and the ASR XL total hip replacement (ASR XL THR) system with very different market approval processes and (2) whether their use was corroborated by clinical trials published in the peer-reviewed literature. Methods - The literature was searched for any clinical studies that reported outcomes of the BHR, ASR HRA and ASR XL THRs. Data from 7 national hip arthroplasty registers were collected and the number of annually implanted devices was matched to those reported in the literature. Results - The cumulative number of implanted and published BHRs grew proportionally with a small lag. The growth of implanted BHRs started to decline at the same time as the ASR HR was introduced. With regard to ASR HRAs, the cumulative proportion of implanted hips and those included in the published studies grew disproportionately after the introduction of the ASR in 2003. For ASR XL THRs, the disproportionality is even higher. Interpretation - The adoption of ASR hip replacements did not follow the proposed stepwise introduction of orthopedic implants. The adoption and use of any new implant should follow a strict guideline and algorithm even if the theoretical basis or the results of preclinical studies are excellent.
| S-EPMC5560208 | biostudies-literature
Project description:Background and purposeUltrasound is used for imaging of pseudotumors associated with metal-on-metal (MoM) hips. Ultrasound has been compared with magnetic resonance imaging, but to date there have been no studies comparing ultrasound findings and revision findings.MethodsWe evaluated the sensitivity and specificity of preoperative ultrasound for detecting pseudotumors in 82 patients with MoM hip replacement (82 hips). Ultrasound examinations were performed by 1 of 3 musculoskeletal radiologists, and pseudotumors seen by ultrasound were retrospectively classified as fluid-filled, mixed-type, or solid. Findings at revision surgery were retrieved from surgical notes and graded according to the same system as used for ultrasound findings.ResultsUltrasound had a sensitivity of 83% (95% CI: 63-93) and a specificity of 92% (CI: 82-96) for detecting trochanteric region pseudotumors, and a sensitivity of 79% (CI: 62-89) and a specificity of 94% (CI: 83-98) for detecting iliopsoas-region pseudotumors. Type misclassification of pseudotumors found at revision occurred in 8 of 23 hips in the trochanteric region and in 19 of 33 hips in the iliopsoas region.InterpretationDespite the discrepancy in type classification between ultrasound and revision findings, the presence of pseudotumors was predicted well with ultrasound in our cohort of failed MoM hip replacements.
| S-EPMC4443452 | biostudies-literature
Project description:Some early failures of metal-on-metal (MoM) hip replacements associated with elevated wear have caused concerns for the use of this bearing combination. Simulator studies have shown that microseparation and its associated rim contact and edge loading may produce the most severe wear in MoM bearings. It is generally recognized that this high wear can be attributed to the high contact stress of the head on the rim of the cup. In this study, an improved finite element contact model that incorporates an elastic-perfectly plastic material property for cobalt-chrome alloy of the metal bearing was developed in an attempt to provide an accurate prediction of the stress and strain for the rim contact. The effects of the microseparation displacement (0.1-2 mm), cup inclination angle (25-65°) and cup rim radius (0.5-4 mm) on the contact stress/strain were investigated. The results show that a translational displacement >0.1 mm under a load >0.5 kN can produce a highly concentrated contact stress at the surface of the cup rim which can lead to plastic deformation. This study also suggests that the magnitude of translational displacement was the major factor that determined the severity of the contact conditions and level of stress and strain under microseparation conditions. Future studies will address the effect of surgical translational and rotational malposition and component design on the magnitude of microseparation, contact stress and strain and severity of wear.
| S-EPMC4737106 | biostudies-other
Project description:The discovery of effective therapeutics targeting amyloid-β (Aβ) aggregates for Alzheimer's disease (AD) has been very challenging, which suggests its complicated etiology associated with multiple pathogenic elements. In AD-affected brains, highly concentrated metals, such as copper and zinc, are found in senile plaques mainly composed of Aβ aggregates. These metal ions are coordinated to Aβ and affect its aggregation and toxicity profiles. In this review, we illustrate the current view on molecular insights into the assembly of Aβ peptides in the absence and presence of metal ions as well as the effect of metal ions on their toxicity.
| S-EPMC9906324 | biostudies-literature
Project description:BackgroundIdentification of modifiable risk factors and treatments for osteoarthritis (OA) are needed. Warfarin, a vitamin K antagonist, causes fetal and animal model skeletal abnormalities. Vitamin K insufficiency has been associated with OA, but whether warfarin is also detrimental to OA is not known.MethodsWe conducted a nested case-control study using a UK general practitioner electronic medical records database. We identified cases of knee or hip replacement (KR or HR) from among adults with atrial fibrillation newly prescribed either warfarin or direct oral anticoagulants (DOACs). Cases were matched with four controls by age and sex. We assessed the relation of warfarin compared with DOAC use to risk of joint replacement using conditional logistic regression. We also evaluated different durations of warfarin use.ResultsWe identified 857 subjects with KR or HR (cases), of whom 64.6% were warfarin users, and 3428 matched controls, of whom 56.1% were warfarin users (mean age 75, 47% female). Warfarin users had a 1.59 times higher risk of joint replacement than DOAC users (adjusted OR 1.59, 95% CI 1.31 to 1.92). Longer duration of warfarin use was associated with higher risk of joint replacement in comparison with <1 year of warfarin use.ConclusionWarfarin, a vitamin K antagonist, was associated with greater risk of KR and HR (an indicator for end-stage knee OA) than DOAC use, supporting the importance of adequate vitamin K functioning in limiting OA progression.
| S-EPMC8361882 | biostudies-literature
Project description:Background:The homeostasis of metal ions, such as iron, copper, zinc and calcium, in the brain is crucial for maintaining normal physiological functions. Studies have shown that imbalance of these metal ions in the brain is closely related to the onset and progression of Alzheimer's disease (AD), the most common neurodegenerative disorder in the elderly. Main body:Erroneous deposition/distribution of the metal ions in different brain regions induces oxidative stress. The metal ions imbalance and oxidative stress together or independently promote amyloid-? (A?) overproduction by activating ?- or ?-secretases and inhibiting ?-secretase, it also causes tau hyperphosphorylation by activating protein kinases, such as glycogen synthase kinase-3? (GSK-3?), cyclin-dependent protein kinase-5 (CDK5), mitogen-activated protein kinases (MAPKs), etc., and inhibiting protein phosphatase 2A (PP2A). The metal ions imbalances can also directly or indirectly disrupt organelles, causing endoplasmic reticulum (ER) stress; mitochondrial and autophagic dysfunctions, which can cause or aggravate A? and tau aggregation/accumulation, and impair synaptic functions. Even worse, the metal ions imbalance-induced alterations can reversely exacerbate metal ions misdistribution and deposition. The vicious cycles between metal ions imbalances and A?/tau abnormalities will eventually lead to a chronic neurodegeneration and cognitive deficits, such as seen in AD patients. Conclusion:The metal ions imbalance induces A? and tau pathologies by directly or indirectly affecting multiple cellular/subcellular pathways, and the disrupted homeostasis can reversely aggravate the abnormalities of metal ions transportation/deposition. Therefore, adjusting metal balance by supplementing or chelating the metal ions may be potential in ameliorating AD pathologies, which provides new research directions for AD treatment.
| S-EPMC7119290 | biostudies-literature
Project description:Metal-on-metal (MoM) hip replacements were used for almost a decade before adverse reactions to metal debris (ARMD) were found to be a true clinical problem. Currently, there is a paucity of evidence regarding the usefulness of systematic screening for ARMD. We implemented a systematic review and meta-analysis to establish the prevalence of revision confirmed ARMD stratified by the use of different screening protocols in patients with MoM hip replacements. Five levels of screening were identified: no screening (level 0), targeted blood metal ion measurement and/or cross-sectional imaging (level 1), metal ion measurement without imaging (level 2), metal ion measurement with targeted imaging (level 3) and comprehensive screening (both metal ions and imaging for all; level 4). 122 studies meeting our eligibility criteria were included in analysis. These studies included 144 study arms: 100 study arms with hip resurfacings, 33 study arms with large-diameter MoM total hip replacements (THR), and 11 study arms with medium-diameter MoM THRs. For hip resurfacing, the lowest prevalence of ARMD was seen with level 0 screening (pooled prevalence 0.13%) and the highest with level 4 screening (pooled prevalace 9.49%). Pooled prevalence of ARMD with level 0 screening was 0.29% and with level 4 screening 21.3% in the large-diameter MoM THR group. In metaregression analysis of hip resurfacings, level 4 screening was superior with regard to prevalence of ARMD when compared with other levels. In the large diameter THR group level 4 screening was superior to screening 0,2 and 3. These outcomes were irrespective of follow-up time or study publication year. With hip resurfacings, routine cross-sectional imaging regardless of clinical findings is advisable. It is clear, however, that targeted metal ion measurement and/or imaging is not sufficient in the screening for ARMD in any implant concepts. However, economic aspects should be weighed when choosing the preferred screening level.
| S-EPMC4773181 | biostudies-literature
Project description:Background and purposePerioperative hyperglycemia has been associated with adverse outcomes in several fields of surgery. In this observational study, we identified factors associated with an increased risk of hyperglycemia following hip and knee replacement.Patients and methodsWe prospectively monitored changes in glucose following primary hip and knee replacements in 191 patients with osteoarthritis. Possible associations of patient characteristics and operation-related factors with hyperglycemia (defined as glucose > 7.8 mmol/L in 2 consecutive measurements) and severe hyperglycemia (glucose > 10 mmol/L) were analyzed using binary logistic regression with adjustment for age, sex, operated joint, and anesthesiological risk score.Results76 patients (40%) developed hyperglycemia, and 48 of them (25% of the whole cohort) had severe hyperglycemia. Glycemic responses were similar following hip replacement and knee replacement. Previously diagnosed diabetes was associated with an increased risk of hyperglycemia and severe hyperglycemia, compared to patients with normal glucose metabolism, whereas newly diagnosed diabetes and milder glucose metabolism disorders had no effect. In patients without previously diagnosed diabetes, increased values of preoperative glycosylated hemoglobin (HbA1c) and fasting glucose on the day of operation were associated with hyperglycemia. Higher anesthesiological risk score-but none of the operation-related factors analyzed-was associated with an increased risk of hyperglycemia.InterpretationPerioperative hyperglycemia is common in primary hip and knee replacements. Previously diagnosed diabetes is the strongest risk factor for hyperglycemia. In patients with no history of diabetes, preoperative HbA1c and fasting glucose on the day of operation can be used to stratify the risk of hyperglycemia.
| S-EPMC4404767 | biostudies-literature