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This document provides information on the topic of cobalt toxicity in patients with metal-on-metal (MoM) hip implants. Cobalt toxicity can lead to various symptoms and complications, including peripheral neuropathy, hearing loss, cardiomyopathy, and hypothyroidism. The diagnosis involves elevated cobalt levels, confirmed findings consistent with cobalt toxicity, and exclusion of other causes. Treatment options include symptomatic management, chelation therapy, and revision of the MoM hip implant. Early detection is important for better outcomes. [Extracted from the article]

Introduction: Cobalt toxicity in patients with hip arthroplasty is a rare complication, but it should be considered in those patients who, after a ceramic fracture, were implanted with a metal-on-polyethylene prosthesis. The complete removal of ceramic particles during revision surgery can be complicated. If the bearing surface is replaced with a metal-on-polyethylene prosthesis, these residual ceramic particles may wear down the chrome-cobalt head, producing localised metallosis. This can trigger blood metal ion levels to rise, causing systemic toxicity. Visual and auditory alterations, cognitive deterioration, hypothyroidism, neuropathy, cardiomyopathy, anorexia, fatigue, diabetes, polycythemia, and respiratory and cutaneous symptoms are some of the clinical manifestations of prosthetic cobaltism. Case description: A young patient presented with multiorgan failure secondary to cobalt toxicity after a ceramic fracture and revision with a metal-on-polyethylene prosthesis; his serum cobalt and chromium levels were 652 μg/L and 270 μg/L, respectively. The patient needed a heart transplant after presenting with cobalt-induced cardiogenic shock. Conclusions: In a patient with a ceramic fracture who is subjected to revision surgery with a metal-on-polyethylene bearing, it is necessary to rule out the possibility of cobalt intoxication. Serum cobalt levels > 20 μg/L are inadmissible; in these cases, surgical treatment should be considered in the short term. A wide synovectomy and replacement of components should be performed with hard friction options, preferably with a ceramic-on-ceramic prosthesis. [ABSTRACT FROM AUTHOR]

Dear Editor, We read with great interest the letter from Pelclova and Lach [[1]] on the efficacy of unithiol (2,3-dimercaptopropanesulfonate) and acetylcysteine in a patient with arthroplastic cobalt toxicity. Acetylcysteine increases cobalt urinary excretion and consistently maintains the serum cobalt concentration less than the threshold of 10 g/L, which we believe to be the goal in patients with metal-on-metal implants in order to minimise cobalt toxicity from the existing prosthesis [[3]]. The authors stated that chelation therapy, either with unithiol or acetylcysteine, is often clinically inefficient in patients with very elevated cobalt concentrations (greater than 100 g/L) as long as the damaged prosthesis remains I in situ i . [Extracted from the article]

We conclude that treatment with either unithiol or acetylcysteine is inefficient in patients with very elevated serum cobalt concentrations, especially greater than 100 µg/L, as long as the damaged prosthesis remains I in situ i . Dear Editor, Previously [[1]] we reported a 56-year-old man with severe cobalt poisoning from a damaged metal-on-ceramic hip prosthesis. However, her serum cobalt concentration reached 221 µg/L in February 2022 on the day of the surgery, which subsequently decreased to 51 µg/L 11 days after surgery, 10 µg/L 2.5 months after surgery, and 3 µg/L 6 months after surgery, all without further treatment. [Extracted from the article]

This case illustrates the potential for systemic cobalt toxicity in non-metal-on-metal bearings and its potentially devastating consequences. We present a 71-year-old male with grinding sensations in his right hip following ceramic-on-ceramic total hip arthroplasty (THA). After diagnosing a fractured ceramic liner, the hip prosthesis was revised into a metal-on-polyethylene bearing. At one year postoperatively, X-rays and MARS-MRI showed a fixed reversed hybrid THA, with periarticular densities, flattening of the femoral head component, and a pattern of periarticular metal wear debris and pseudotumor formation. Before revision could take place, the patient was admitted with the clinical picture of systemic cobalt toxicity, supported by excessively high serum cobalt and chromium levels, and ultimately died. At autopsy dilated cardiomyopathy as cause of death was hypothesized. A third body wear reaction between ceramic remnants and the metal femoral head very likely led to excessive metal wear, which contributed systemic cobalt toxicity leading to neurotoxicity and heart failure. This case emphasizes that fractured ceramic-on-ceramic bearings should be revised to ceramic-on-ceramic or ceramic-on-polyethylene bearings, but not to metal-on-polyethylene bearings. We aim to increase awareness among orthopedic surgeons for clinical clues for systemic cobalt intoxication, even when there is no metal-on-metal bearing surface. [ABSTRACT FROM AUTHOR]

Cobalt (Co) and its compounds are widely distributed in nature and are part of numerous anthropogenic activities. Although cobalt has a biologically necessary role as metal constituent of vitamin B 12 , excessive exposure has been shown to induce various adverse health effects. This review provides an extended overview of the possible Co sources and related intake routes, the detection and quantification methods for Co intake and the interpretation thereof, and the reported health effects. The Co sources were allocated to four exposure settings: occupational, environmental, dietary and medical exposure. Oral intake of Co supplements and internal exposure through metal-on-metal (MoM) hip implants deliver the highest systemic Co concentrations. The systemic health effects are characterized by a complex clinical syndrome, mainly including neurological (e.g. hearing and visual impairment), cardiovascular and endocrine deficits. Recently, a biokinetic model has been proposed to characterize the dose-response relationship and effects of chronic exposure. According to the model, health effects are unlikely to occur at blood Co concentrations under 300 μg/l (100 μg/l respecting a safety factor of 3) in healthy individuals, hematological and endocrine dysfunctions are the primary health endpoints, and chronic exposure to acceptable doses is not expected to pose considerable health hazards. However, toxic reactions at lower doses have been described in several cases of malfunctioning MoM hip implants, which may be explained by certain underlying pathologies that increase the individual susceptibility for Co-induced systemic toxicity. This may be associated with a decrease in Co bound to serum proteins and an increase in free ionic Co 2+ . As the latter is believed to be the primary toxic form, monitoring of the free fraction of Co 2+ might be advisable for future risk assessment. Furthermore, future research should focus on longitudinal studies in the clinical setting of MoM hip implant patients to further elucidate the dose-response discrepancies. [ABSTRACT FROM AUTHOR]

Metal toxicity from metal-on-metal hip replacements is now well documented and several large series have reported local reactions. Although less common, there are reports of similar reactions from failed ceramic liners. Systemic effects documented in literature have been grouped into cardiac, neuro-ocular and thyroid signs.~Introduction~Background~We report a case of a patient who had revision for fractured ceramic liner to metal on polyethylene. Third body effect of the ceramic particles led to wear through of the poly liner and the head directly articulating with metal shell. He developed cardiac and neurological features of cobalt toxicity in addition to extensive soft tissue destruction. Revision of the bearing surfaces and synovectomy led to clinical improvement and fall in metal ion levels.~Methods and Results~Results~We recommend 2-stage revision in such situations and close monitoring of all these patients.~Conclusions~Conclusions [ABSTRACT FROM AUTHOR]

The article presents a case report of an 84-year-old woman with a orthopaedic history who experienced generalized pruritic eczematous rash. She had undergone a metal-on-metal (MoM) right total hip replacement for a fractured femur neck in May 2009. Skin biopsy of the rash revealed urticarial features with no overt histological evidence of a drug eruption. Diagnosis of the patient revealed systemic allergic dermatitis (SAD) caused by cobalt.

Systemic poisoning related to cobalt–chromium total hip arthroplasty can affect multiple organs. In the otolaryngologic area the most frequent symptoms are tinnitus and hearing loss. In this report, we describe 2 patients with cobalt-containing hip prostheses who presented with otologic symptoms. The first case describes a patient with an extremely high cobalt blood level, which we believe may be one of the highest reported to date, after replacing a broken ceramic-on-ceramic prosthesis with a metal-on-metal prosthesis. This patient suffered all known complications associated with cobalt poisoning and survived. The second case, a female patient with a left resurfacing metal-on-metal prothesis, presented with bilateral continuous high-pitched tinnitus that started 8 months after surgery. Orthopedic surgeons and otologists should be vigilant for cobalt-induced ototoxicity in patients with metal-on-metal total hip prostheses. [ABSTRACT FROM AUTHOR]

Cobalt-containing alloys are useful for orthopedic applications due to their low volumetric wear rates, corrosion resistance, high mechanical strength, hardness, and fatigue resistance. Unfortunately, these prosthetics release significant levels of cobalt ions, which was only discovered after their widespread implantation into patients requiring hip replacements. These cobalt ions can result in local toxic effects--including peri-implant toxicity, aseptic loosening, and pseudotumor--as well as systemic toxic effects--including neurological, cardiovascular, and endocrine disorders. Failing metal-on-metal (MoM) implants usually necessitate painful, risky, and costly revision surgeries. To treat metallosis arising from failing MoM implants, a synovial fluid-mimicking chelator was designed to remove these metal ions. Hyaluronic acid (HA), the major chemical component of synovial fluid, was functionalized with British anti-Lewisite (BAL) to create a chelator (BAL-HA). BAL-HA effectively binds cobalt and rescues in vitro cell vitality (up to 370% of cells exposed to IC50 levels of cobalt) and enhances the rate of clearance of cobalt in vivo (t1/2 from 48 h to 6 h). A metallosis model was also created to investigate our therapy. Results demonstrate that BAL-HA chelator system is biocompatible and capable of capturing significant amounts of cobalt ions from the hip joint within 30 min, with no risk of kidney failure. This chelation therapy has the potential to mitigate cobalt toxicity from failing MoM implants through noninvasive injections into the joint. [ABSTRACT FROM AUTHOR]

Introduction: An increase in blood serum metal ion levels is seen after implantation of all metal-on-metal (MoM) hip prosthesis. Systemic complaints contributed to raised cobalt ion concentrations in patients with MoM arthroplasty may lead to a variety of symptoms. 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. Methods: A cohort study was conducted. Patients with both unilateral and bilateral, resurfacing and large head metal on metal total hip arthroplasties (LHMoM THA) were included. Cobalt ion concentrations were measured by inductively coupled plasma mass spectrometry. Based on the known cobalt toxicity symptoms of case-reports and toxicology reports a new non-validated questionnaire was developed. Analysis was performed on two groups; a low cobalt ion concentration group and a high cobalt ion concentration group. Results: A total of 62 patients were included with a mean age at surgery of 60.8 ± 9.3 years and a mean follow up of 6.3 ± 1.4 years. Mean cobalt ion concentrations were 104 ± 141 nmol/L (9-833). Based on the different thresholds (120-170 or 220 nmol/L) the low cobalt ion concentration group consisted of 44 (71%), 51 (82%) or 55 (89%) subjects respectively. In the 120 nmol/L and 170 nmol/L thresholds a significant difference in age was found. The composite score for OVS increased from 54% to 57%-68% with rising threshold value, a hint at the correlation between ion concentration and symptom prevalence Discussion: Ocular-vestibular symptoms were more common in high cobalt ion concentration groups for the three threshold levels tested and with increasing prevalence for higher threshold values. With regards to proactively inquired, self-reported symptoms the threshold where effects may be present could be lower than values currently applied in clinical follow-up [ABSTRACT FROM AUTHOR]

Introduction. One in eight of all total hip replacements requires revision within 10 years, 60% because of wear-related complications. The bearing surfaces may be made of cobalt/chromium, stainless steel, ceramic, or polyethylene. Friction between bearing surfaces and corrosion of non-moving parts can result in increased local and systemic metal concentrations. Objectives. To identify and systematically review published reports of systemic toxicity attributed to metal released from hip implants and to propose criteria for the assessment of these patients. Methods. Medline (from 1950) and Embase (from 1980) were searched to 28 February 2014 using the search terms (text/abstract) chrom* or cobalt* and [toxic* or intox* or poison* or adverse effect or complication] and [prosthes* or 'joint replacement' or hip or arthroplast*] and PubMed (all available years) was searched using the search term (('Chromium/adverse effects'[Mesh] OR 'Chromium/poisoning'[Mesh] OR 'Chromium/toxicity'[Mesh]) OR ('Cobalt/adverse effects'[Mesh] OR 'Cobalt/poisoning'[Mesh] OR 'Cobalt/toxicity'[Mesh])) AND ('Arthroplasty, Replacement, Hip'[Mesh] OR 'Hip Prosthesis'[Mesh]). These searches identified 281 unique references, of which 23 contained original case data. Three further reports were identified from the bibliographies of these papers. As some cases were reported repeatedly the 26 papers described only 18 individual cases. Systemic toxicity. Ten of these eighteen patients had undergone revision from a ceramic-containing bearing to one containing a metal component. The other eight had metal-on-metal prostheses. Systemic toxicity was first manifest months and often several years after placement of the metal-containing joint. The reported systemic features fell into three main categories: neuro-ocular toxicity (14 patients), cardiotoxicity (11 patients) and thyroid toxicity (9 patients). Neurotoxicity was manifest as peripheral neuropathy (8 cases), sensorineural hearing loss (7) and cognitive decline (5); ocular toxicity presented as visual impairment (6). All these neurological features, except cognitive decline, have been associated with cobalt poisoning previously. Type of prosthesis and blood metal concentrations. Where blood or serum metal concentrations were reported ( n = 17 for cobalt and n = 14 for chromium), the median cobalt concentration was 398 (range, 13.6-6521) μg/L and the median chromium concentration was 48 μg/L (in whole blood) (range, 4.1-221 μg/L including serum and blood values). Those patients reported to have systemic features who had received a metal-on-metal prosthesis ( n = 8) had a median peak blood cobalt concentration of 34.5 (range, 13.6-398.6) μg/L; those with a metal-containing revision of a failed ceramic prosthesis ( n = 10) had a median blood cobalt concentration of 506 (range, 353-6521) μg/L. Management. The most common treatment was removal of the metal-containing prosthesis, undertaken in all but 2 patients. This was usually associated with a fall in circulating cobalt concentration and improvement in some or all features. Clinical and toxicological assessment of systemic features. We propose the following criteria for assessing the likelihood that clinical features are related to cobalt toxicity: clinical effects consistent with the known neurological, cardiac, or thyroidal effects of cobalt, and for which any other explanation is less likely; increased blood cobalt concentrations (substantially higher than those in patients with well-functioning prostheses) several months after hip replacement; a fall in the blood cobalt concentration, usually accompanied by signs of improvement in features. When judged by these criteria, the systemic features in 10 of the reported cases are likely to be related to cobalt exposure from a metal-containing hip prosthesis. Conclusions. Rarely, patients exposed to high circulating concentrations of cobalt from failed hip replacements develop neurological damage, hypothyroidism and/or cardiomyopathy, which may not resolve completely even after removal of the prosthesis. The greatest risk of systemic cobalt toxicity seems to result from accelerated wear of a cobalt-containing revision of a failed ceramic prosthesis, rather than from primary failure of a metal-on-metal prosthesis. [ABSTRACT FROM AUTHOR]

Background: With the re-popularity of metal-on-metal (MoM) bearing in recent years, the cobalt toxicity has been a cause for concern in the total hip replacement surgery by both physicians and patients. Methods: MG-63 cell line was cultured in vitro and incubated with cobalt (II) chloride (CoCl2) and/or with astaxanthin (ASX) for 24 h. MTT assay was conducted to evaluate the cell viability after cobalt exposure and ASX treatment. Fluorescence-activated cell sorting (FACS) analysis was performed to examine the reactive oxygen species (ROS) level. Quantitative real-time polymerase chain reaction (PCR) was adopted to determine the mRNA levels of related targets. And western blot analysis was used to examine the protein expressions. One-way ANOVA with posttest Newman-Keuls multiple comparisons was adopted to analysis all the obtained data. Results: In the current study, ASX exhibited significant protective effect against the Co(II)-induced cytotoxicity in MG-63 cell line. We also found that ASX protected the cells against Co-induced apoptosis by regulating the expression of Bcl-2 family proteins. Besides, heme oxygenase 1 (HO-1) could be activated by Co exposure; ASX treatment significantly inhibited HO-1 activation, suppressing the oxidative stress induced by Co exposure. Moreover, c-Jun N-terminal Kinase (JNK) phosphorylation was shown to participate in the signaling pathway of the protective effect of ASX. However, knockdown of JNK expression by siRNA transfection or JNK inhibitor SP600125 treatment did not affect the protective effect of ASX against cobalt cytotoxicity in MG-63 cells. Conclusions: ASX mitigated cobalt cytotoxicity in the MG-63 cells by modulating the oxidative stress. And ASX could be a promising therapy against cobalt toxicity in the hip articulation surgery. [ABSTRACT FROM AUTHOR]

Introduction. Heavy metal intoxication after arthroplasty is extremely rare but could be lethal. Case Report. We report the case of a 69-year-old woman, who presented intense systemic symptoms of chromium-cobalt intoxication after revision of per-operative fractured ceramic components with metal-on-polyethylene. Systemic toxicity occurred a year after surgery and expressed brutally with mostly central neurological symptoms. Chelation associated with revision surgery allowed rapid regression of all symptoms. Conclusion. Revision of fractured ceramic, even per-operatively, should not be done with metal-on-polyethylene components, in order to avoid potentially lethal metal intoxication. [ABSTRACT FROM AUTHOR]

Metallosis with subsequent cardiac involvement is a possible long‐term complication of hip arthroplasty. We report the case of a young female referred to our centre for the suspicion of cardiac amyloidosis presenting with low electrocardiogram voltage, left ventricular hypertrophy, pericardial effusion, and global and longitudinal systolic impairment with apical sparing pattern. Her medical history was remarkable for arthroplasty in the context of congenital hip dysplasia. Two years prior to presentation, she underwent revision surgery for prosthesis malfunction, and tissue metallosis was initially documented. At the current presentation, cobalt metallosis was confirmed, as the circulating cobalt and chromium levels were severely elevated. The accurate diagnosis prompted the removal of the cobalt source with extensive tissue debridement and the use of chelating agents. Reversal of the cardiac abnormalities occurred as the circulating cobalt levels returned to normal. [ABSTRACT FROM AUTHOR]

A forty-year-old man experienced worsening heart failure four years following bilateral complicated total hip replacement. His condition was extensively worked up but no underlying pathology was immediately evident. Given the cobalt-chromium alloy component present in the hip arthroplasties, the raised cobalt blood levels, and a fitting clinical picture coupled with radiological findings, the patient underwent right hip revision. Evidence of biotribocorrosion was present on direct visualisation intraoperatively. The patient subsequently experienced symptomatic improvement (NYHA class III to class I) and echocardiography showed recovery of ejection fraction. Cobalt exists as a bivalent and trivalent molecule in circulation and produces a cytotoxicity profile similar to nanoparticles, causing neurological, thyroid, and cardiological pathology. Blood levels are not entirely useful as there is no identifiable conversion factor for levels in whole blood, serum, and erythrocytes which seem to act independently of each other. Interestingly cobalt cardiomyopathy is frequently compounded by other possible causes of cardiomyopathy such as alcohol and a link has been postulated. Definitive treatment is revision of the arthroplasty as other treatments are unproven. [ABSTRACT FROM AUTHOR]

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Background: Metal-on-metal (M-M) total hip arthroplasty (THA) has shown adverse reactions to metal debris, abnormal soft-tissue reactions, and high blood metal ion levels. This study aims to: (1) assess whether the toxicity of high levels of ions is related to altered oxidative stress and (2) evaluate tribological factors related to increased blood levels of chromium (Cr) and cobalt (Co) ions. Methods: A cross-sectional analytical descriptive study was conducted on 75 patients. A total of 25 underwent M-M THA, 25 ceramic-on-metal (C-M) THA, and 25 were on the THA waiting list. Ion metallic levels in blood, oxidative stress, physical activity, and implant position were compared. Results: In the M-M group, Co and Cr levels were significantly higher than those found in the C-M group and the control group (p < 0.01). We found no differences in terms of oxidative stress between the groups. Also, we did not find a correlation between metal blood levels and oxidative stress indicators, the physical activity of the patients or the position of the implants between groups. Conclusions: The use of M-M bearing surfaces in THA raises the levels of metals in the blood without modifying oxidative stress regardless of the physical activity levels of the patients. Therefore, although patients with M-M bearings require close monitoring, it does not seem necessary to recommend the restriction of physical activity in patients with M-M or C-M arthroplasties. [ABSTRACT FROM AUTHOR]

Purpose: Hip arthroplasty with metal-on-metal bearings like hip resurfacing results in the release of metallic ions. In parallel, like every metallic implant, knee arthroplasty implants undergo passive corrosion. We analyzed blood levels of cobalt and chromium ions in patients who have a hip resurfacing arthroplasty and compared them to patients who have undergone knee arthroplasty at a minimum follow-up of one year. The hypothesis was that there is no difference in the ion release between hip resurfacing and knee arthroplasty. Methods: Sixty-three patients who underwent knee arthroplasty were compared to a cohort of 132 patients who underwent hip resurfacing. The blood levels of cobalt and chromium ions were determined preoperatively and at six and 12 months postoperatively and then compared between groups. We analyzed the relationship between ion release and the change in clinical outcome scores (Harris Hip score, Oxford Hip score, Merle D'Aubigné Postel score, Oxford Knee score, International Knee Society score), the BMI, sex, physical activity, implant size and inclination of the acetabular implant (hip resurfacing patients only). Mixed linear models were used to assess the changes in ion blood levels over time. Results: The cobalt blood levels were higher in the first 6 months in the resurfacing group (0.87 ug/L vs 0.67 ug/L; p = 0.011), while it was higher in the knee arthroplasty group at 12 months (1.20 ug/L vs 1.41 ug/L; p = 0.0008). There were no significant differences in chromium levels during the follow-up period. Conclusion: The increase in metal ion release after knee arthroplasty is as high as after hip resurfacing at the one year follow-up. The monitoring of this parameter probably should not be recommended in case of good clinicals outcomes. [ABSTRACT FROM AUTHOR]

In 1966, the "beer drinker's cardiomyopathy" was described in Quebec City, Canada among heavy drinkers following the addition of cobalt by breweries for foam stabilisation. Almost half of those affected died. A similar process has been proposed for cardiovascular periprosthetic metallosis in patients receiving cobalt-containing hip prostheses. This case describes a young man with congenital osteonecrosis treated with cobalt containing prosthetic arthroplasty. Postoperatively, he developed pericardial effusion, dilated cardiomyopathy, polycythemia and lactic acidosis. His serum cobalt level was 156 mcg/L (normal 0.1 - 0.4 mcg/L). Metal-on-metal hip implants have been associated with arthroprosthetic cobaltisim, a presentation indistinguishable from "beer drinker's cardiomyopathy." Up to 35% of hip replacements utilize metal-on-metal bearing surfaces, making this a potentially wide-spread and relatively underappreciated etiology of postoperative idiopathic cardiomyopathy. This clinical vignette emphasizes the importance of considering cobalt cardio-toxicity, or "beer drinker's cardiomyopathy," as a differential diagnosis of idiopathic cardiomyopathy following total hip arthroplasty. [ABSTRACT FROM AUTHOR]

A 61-year-old previously healthy woman developed progressive hearing and visual loss over a period of 2-3 months prior to admission. Her medical/surgical history was remarkable for a left hip arthroplasty 11 years ago requiring revision approximately 6 months prior to admission. After dislocating the revised hip, she re-presented to her surgeon and underwent a closed reduction. Several weeks following the reduction, the patient began having polyuria and symptoms of hearing and vision loss along with numbness in her extremities and abdominal region. [ABSTRACT FROM AUTHOR]

Total hip arthroplasty (THA) is a successful orthopaedic surgical procedure, and its longevity depends on bearing components and implant fixation. Optimizing polyethylene and ceramics has led to improved wear parameters and contributed to improved long-term outcomes. The present systematic review investigated whether time span from implantation, patient characteristics and performance status exert an influence on liner wear and head migration in THA. This study was conducted in conformity to the 2020 PRISMA guidelines. All the clinical investigations which reported quantitative data on the amount of liner wear and head migration in THA were considered. Only studies which reported quantitative data at least on one of the following patient characteristics were suitable: mean age, mean BMI (kg/m2), sex, side, time span between the index THA and the last follow-up (months) were eligible. A multiple linear model regression analysis was employed to verify the association between patient characteristics and the amount of liner wear and/or head migration. The Pearson Product-Moment Correlation Coefficient was used to assess the association between variables. Data from 12,629 patients were considered. The mean length of the follow-up was 90.5 ± 50.9 months. The mean age of patients at surgery was 58.4 ± 9.4 years, and the mean BMI was 27.2 ± 2.5 kg/m2. 57% (7199 of 12,629 patients) were women, and in 44% (5557 of 12,629 patients) THAs were performed on the left. The mean pre-operative Harris hip score was 46.5 ± 6.0 points. There was evidence of a moderate positive association between the amount of liner wear and the time elapsed between the index surgery to the follow-up (P = 0.02). There was evidence of a moderate positive association between the amount of head migration and the time elapsed between the index surgery to the follow-up (P = 0.01). No further statistically significant association was found. The time elapsed between the index surgery to the follow-up was the most important factor which influence the head migration and liner wear in THA. Patients' characteristics and preoperative physical activity did not influence the amount of head migration and liner wear. [ABSTRACT FROM AUTHOR]

Cobalt-containing hip prosthesis may cause systemic toxicity due to the release of cobalt from metal-on-metal (MoM) joint arthroplasty into the bloodstream. High cobalt blood levels can lead to a variety of clinical manifestations, mimicking other disorders, especially autoimmune, hematologic, and infectious diseases. Our purpose is to describe a clinical case of cobalt hip prosthesis intoxication mimicking an autoimmune disease, with systemic inflammation signs, arthro-myalgias unrelated to overt synovitis, and multiple autoantibody positivity. A 69-years-old woman presented with a 1-year history of right coxalgia, recurrent fever, arthro-myalgias, mediastinal and right iliac reactive lymphadenopathy. She underwent hip replacement surgery seven years earlier. The physical examination was unremarkable except for right hip pain. Laboratory tests showed markedly increased inflammatory indices and microbiological tests were all negative. Ultrasound-guided arthrocentesis of right hip yielded limpid fluid with negative cultures. Increased cobalt levels in plasma and urine showed metal intoxication. Magnetic resonance imaging with metal artifact reduction sequence (MARS) confirmed a periprosthetic mass as usually seen in reaction to metal debris. Prosthesis substitution was performed with a resolution of the clinical picture and normalization of cobalt levels. [ABSTRACT FROM AUTHOR]

Purpose: Although rare, fractures of ceramic components are difficult to revise, mainly due to the presence of residual ceramic debris that can cause catastrophic wear of the replacement components. Modern ceramic-on-ceramic bearings are suggested to improve outcomes of revision total hip arthroplasty (THA) for ceramic fractures. However, there are few published reports of mid-term outcomes of revision THA using ceramic-on-ceramic bearings. We evaluated clinical and radiographic outcomes of 10 patients who received ceramic-on-ceramic bearings during revision THA for ceramic fractures. Methods: All patients but one received fourth-generation Biolox Delta bearings. Clinical evaluation was performed using the Harris hip score at latest follow-up, and all patients received a radiographic evaluation to analyze the fixation of the acetabular cup and of the femoral stem. Osteolytic lesions and the presence of ceramic debris were noted. Results: After a mean follow-up of 8.0 years, there were no complications or implant failures, and all patients reported satisfaction with their implant. The average Harris hip score was 90.6. There was neither osteolysis nor loosening, but despite our extensive synovial debridement, ceramic debris was noted in the radiographs of five patients (50%). Conclusion: We report excellent mid-term outcomes, with no implant failures after eight years despite ceramic debris being found in a significant proportion of patients. We conclude that modern ceramic-on-ceramic bearings are an advantageous option for the revision of THA due to the fracture of initial ceramic components. [ABSTRACT FROM AUTHOR]

The present systematic review investigated the concentration of chromium (Cr) and cobalt (Co) in serum in patients who have undergone total hip arthroplasty (THA). The first outcome of interest was to investigate the mean concentration in serum of Cr and Co using different material combinations and to verify whether their concentrations change significantly using different patterns of head and liner in THA. The second outcome of interest was to investigate whether the time elapsed from the index surgery to the follow-up, BMI, sex, and side exert an influence on the mean concentration of Cr and Co in serum in patients who have undergone THA. The following material combinations were investigated (head-liner): Ceramic-Co Cr (CoCr), CoCr-CoCr, CoCr-Polyethylene, CoCr high carbide-CoCr high carbide. Data from 2756 procedures were retrieved. The mean length of follow-up was 69.3 ± 47.7 months. The ANOVA test evidenced good comparability in age, length of follow-up, BMI, and sex (P > 0.1). In patients who have undergone THA, the mean concentration in the serum of Co ranged between 0.5 µg/L and 3.5 µg/L, and the mean concentration of Cr from 0.6 to 2.6 µg/L. The difference in the concentration of Co and Cr in serum is strictly related to the implant configuration, with the coupling CoCr-CoCr showing the highest and CoCr-Polyethylene showing the lowest concentration. Patient characteristics, BMI, sex, side and the time elapsed from the index surgery to the last follow-up did not exert a significant influence on the concentration of Co and Cr in serum in patients who have undergone total hip arthroplasty (THA). [ABSTRACT FROM AUTHOR]

This unique study provides information on Cr species and their distribution in periprosthetic tissues of patients with metal‐on‐polyethylene joint implants. Co–Cr–Mo alloy has been widely used in joint replacement and represents a source of metal derived species. In the case of chromium, previous studies on periprosthetic tissues revealed mainly Cr(III) distribution, whereas the potential release of carcinogenic Cr(VI) species has been still a subject of debate. Here, an analytical approach utilizing speciation and fractionation was developed to analyze periprosthetic tissue samples collected from wide range of patients with failed total hip or knee replacements. The results reveal that Cr(III) is mainly released in the form of insoluble CrPO4 and Cr2O3 particles. The highest Cr contents were found in periprosthetic tissues of patients suffering from aseptic loosening and having more Cr‐based implants in the body. Cr species penetrated tissue layers, but their levels decreased with the distance from an implant. The detailed speciation/fractionation study carried out using the set of consecutive periprosthetic tissues of a patient with extensive metallosis showed the presence of trace amounts of free Cr(III), nanoparticles, and metal‐protein complexes, but the majority of Cr still occurred in CrPO4 form. Carcinogenic Cr(VI) species were not detected. Up to date, there is no published human tissue study focused on the detailed speciation of both soluble and insoluble Cr‐based species in the context of failing total hip and knee replacements. [ABSTRACT FROM AUTHOR]

Metal‐on‐polyethylene (MoP) total hip arthroplasty (THA) prostheses are known to release metal debris. Basic science studies suggest that metal implants induce a pro‐inflammatory response that ultimately chemoattracts leukocytes including macrophages and neutrophils to the surgical site. This raises concern of higher risk of infection with these prostheses through the "trojan horse" mechanism by which neutrophils and macrophages transport intracellular pathogens from a remote site. This study compared the infection occurrence between MoP and ceramic‐on‐polyethylene (CoP) implants to determine if a higher infection rate in MoP is present. We reviewed a consecutive series of 6052 CoP and 4550 MoP primary THA patients from 2015 to 2019. The occurrence of periprosthetic joint infection at 2 years was defined according to the 2018 ICM definition. Statistical analysis consisted of descriptive statistics, univariate analysis, and regression modeling. When compared to CoP, MoP patients were older, included more females, had a higher body mass index, and more commonly affected by comorbidities according to Elixhauser's score. Total revisions were higher in the MoP group (3.19% vs. 2.41%) The absolute incidence of PJI was higher in MoP (2.40% vs. 1.64%). When we adjusted for confounding factors, MoP was found independently associated with a higher PJI risk. Despite MoP and CoP both being widely used for primary THA, we found a higher incidence of PJI in MoP patients. The association remained significant when controlled for possible confounders. We hypothesize that leukocyte recruitment to these implants may play a role and should be further investigated. [ABSTRACT FROM AUTHOR]

aima I Abdel Hamid,1 Mohamed E Attia,2 Jon M Hirshon,3,4 Mohamed El-Shinawi,5,6 Moustafa El-Hussaini,7 Maged El-Setouhy7,81Forensic Medicine and Clinical Toxicology Department, Faculty of Medicine, Zagazig University, Zagazig, Egypt; 2Orthopedics Departments, Faculty of Medicine, Zagazig University, Zagazig, Egypt; 3Department of Emergency Medicine, University of Maryland, School of Medicine, Baltimore, MD, USA; 4Department of Epidemiology and Public Health, University of Maryland, School of Medicine, Baltimore, MD, USA; 5Department of General Surgery, Faculty of Medicine, Ain Shams University, Cairo, Egypt; 6Galala University, Galala City, Suez, Egypt; 7Department of Community, Environmental and Occupational Medicine, Faculty of Medicine, Ain Shams University, Cairo, Egypt; 8Department of Family and Community Medicine, Faculty of Medince, Jazan University, Jazan, Kingdom of Saudi ArabiaCorrespondence: Omaima I Abdel Hamid, Forensic Medicine and Clinical Toxicology Department, Faculty of Medicine, Zagazig University, Zagazig, Egypt, Tel +201001664310, Email [email protected] Introduction: Hip arthroplasty (HA) using implantable metal components is among the commonest orthopedic interventions. However, it can be followed by several complications following corrosion and the release of metal ions. Several studies proved that damaged genomic DNA may contribute to the pathophysiology of mental disorders. Aim: The current work aims to evaluate the psychiatric disorders in metal on polyethylene hip arthroplasty (MOP-HA) patients and its correlation to cobalt/chromium (Co/Cr) levels and genotoxicity. Methods: The work was a longitudinal follow-up study including 34 adults with unilateral primary MOP-HA meeting the inclusion and exclusion criteria. Preoperatively, 6, 12-months-postoperatively, patients were examined for cognitive impairment using mini-mental-state-examination (MMSE), depression using major-depressive-inventory (MDI), and blood samples were collected for estimation of Co/Cr, detection of genotoxicity by single-cell-gel-electrophoresis (comet assay) and serum 8-hydroxy-2'–deoxyguanosine (8-OHdG). Results: Cognitive impairment was reported in 18.5% and 14.8% at 6-months, and 12-months postoperative, respectively. Depressive disorder was recorded in 22.2% at 6-months and 14.8% at 12-months postoperative. The marginal homogeneity tests proved a non-significant difference. There was a non-significant difference in preoperative, 6-months, 12-months postoperative MMSE, and MDI scores. There were significantly increased Co/Cr levels at 6-months postoperative. The levels decreased at 12-months postoperative, however, still significantly higher than preoperative values. There was a significant increase in serum 8-OHdG and the levels were positively correlated to cobalt levels at both 6 and 12-months-postoperative. There was a non-significant difference among preoperative, 6-months, and 12-months postoperative comet assay measurements. Conclusion: From previous findings, we can conclude that will-functioning MOP hip arthroplasty can induce increased ion levels and positively correlated increase in biochemical markers of genotoxicity (8-OHdG). [ABSTRACT FROM AUTHOR]

Background and purpose -- We have previously reported that the whole blood (WB) chromium (Cr) and cobalt (Co) ion levels decrease in the short term after ReCap-M2a-Magnum large-diameter head (LDH) metal-on-metal (MoM) total hip arthroplasty (THA). This study reports long-term metal ion levels and clinical outcomes after ReCap-Magnum THA. Patients and methods -- ReCap-M2a-Magnum LDH THA was used in 1,450 patients in our hospital district from 2005 to 2012. Median follow-up time was 10 years. 991 patients had 2 or more metal ion measurements. The median measurement interval was 4 years. Individual metal ion change was assessed using logarithmic metal ion values in a random coefficient model. Kaplan--Meier survival estimates were calculated for revision surgery for any reason for revision, and separately for metal-related adverse events (metal ions above safe upper limit [SUL], revision due to ARMD, or pseudotumor). Results -- Geometric mean of Cr decreased from 1.8 ppb (geometric standard deviation [GSD] 1.8) to 1.0 ppb (GSD 2.8, p < 0.001). The Co levels decreased from 1.7 ppb (GSD 2.4) to 1.4 ppb (GSD 2.8, p < 0.001). The hip-specific survival was 85% for revision due to any reason at 14 years and the hip-specific survival for any metal-related adverse event was 69% at 14 years. Interpretation -- WB Cr and Co levels continued to decrease in the long-term follow-up of ReCap-M2a-Magnum THA patients. The amount of metal-related adverse events was rather high, but revision surgery was seldom required. We suggest that after 10 years from the implantation a 5-year measurement interval may be sufficient for asymptomatic ReCap-M2a-Magnum patients. [ABSTRACT FROM AUTHOR]

This study aimed to systematically investigate the ototoxic potential of cobalt in patients with a metal-on-metal (MoM) hip implant, using objective auditory and vestibular assessments and a questionnaire. The results of the objective evaluation were published previously, whereas the current study focused on the questionnaire outcome and its relationship to the blood cobalt level. Design and study sample: Twenty patients (33–65 years) with a primary MoM hip implant and 20 non-implanted control subjects, matched for age, gender, and noise exposure, received a questionnaire to evaluate the presence of several hearing and balance symptoms (part 1) and general neurological issues (part 2). Concerning part 1, the proportion of auditory-related symptoms in general (p = 0.022) and tinnitus (p = 0.047) was significantly higher in the MoM patient group, whereas no group difference was found for hyperacusis, increased listening effort, and decreased speech understanding. Concerning part 2, no significant group differences were detected. Within the MoM patient group, the questionnaire outcome was not significantly different between the low-exposure and high-exposure subgroups according to the blood Co level. In line with our previous study, these results potentially imply Co-induced impairment to the auditory system, despite the lack of a clear dose–response relationship. [ABSTRACT FROM AUTHOR]

Recently, catastrophic failure (i.e., dissociation between the metal femoral head and stem due to stem neck deformation) after total hip arthroplasty (THA) has been reported. Early detection of this complication is very important, because it is accompanied by an increased cobalt concentration in the body, which might influence systemic conditions such as heart failure and immune system diseases. However, early detection of stem neck deformation is considered as difficult. In most cases in the literatures, the diagnosis was made at the time of acute dissociation. We report a case of early detection of stem neck deformation with the 'Bowing-head sign' before acute dissociation. The patient is a 71-year old woman complained of a clicking sensation in the right hip during regular follow-up after THA with a 32-mm cobalt/chromium head with polyethylene insert for osteoarthritis performed 7 years previously. The plain radiograph showed that the angle between the metal femoral head and the axis of the stem neck was not perpendicular ('Bowing-head sign'). Dynamic evaluation under fluoroscopy showed movement of the stem neck in the metal femoral head with hip abduction and adduction. Laboratory data showed abnormal serum cobalt (6.3 μg/L, normal < 1 μg/L) and chromium (3.8 μg/L, normal < 5 μg/L) levels. Considering those radiographic findings, deformation of the stem neck due to trunnionosis was diagnosed, and elective revision surgery was performed without any complications. Plain radiographs after THA should be assessed with attention to this complication, 'Bowing-head sign' must not be overlooked. [ABSTRACT FROM AUTHOR]

Background and purpose — The accelerated wear of poorly functioning metal-on-metal (MoM) hip implants may cause elevated whole-blood cobalt (Co) and chromium (Cr) levels. Hematological and endocrinological changes have been described as the most sensitive adverse effects due to Co exposure. We studied whether there is an association between whole-blood Co/Cr levels and leukocyte, hemoglobin, or platelet levels. Patients and methods — We analyzed whole-blood Co and Cr values and complete blood counts (including leukocytes, hemoglobin, platelets) from 1,900 patients with MoM hips. The mean age at the time of whole-blood metal ion measurements was 67 years (SD 10). The mean time from primary surgery to whole-blood metal ion measurement was 8.2 years (SD 3.0). The mean interval between postoperative blood counts and metal ion measurements was 0.2 months (SD 2.7). Results — The median Co value was 1.9 µg/L (0.2–225), Cr 1.6 µg/L (0.2–125), mean leukocyte count 6.7 × 109/L (SD 1.9), hemoglobin value 143 g/L (SD 13), and platelet count 277 × 109/L (SD 70). We did not observe clinically significant correlations between whole-blood Co/Cr and leukocyte, hemoglobin, or platelet counts. Interpretation — Elevated whole-blood Co and Cr values are unlikely to explain abnormal blood counts in patients with MoM hips and the reason for possible abnormal blood counts should be sought elsewhere. [ABSTRACT FROM AUTHOR]

Introduction: Although metallosis is a well-known complication after total hip arthroplasty, little is known about this phenomenon after total (TKA) or unicompartmental knee arthroplasty (UKA). The aim of the present work was to review the current knowledge about the reasons and the diagnostic as well as therapeutic management of metallosis after knee arthroplasty. Materials and methods: A literature search was performed through PubMed until April 2019. Search terms were "metallosis" in combination with "knee", "knee prosthesis", "knee arthroplasty" and "knee replacement", respectively. All publications were analyzed regarding publication year, level of evidence, number of knees/patients treated, type of prosthesis, metallosis cause, time period between primary implantation and metallosis emergence, laboratory examination, treatment, complications and follow up. Results: A total of 38 studies reporting on a total of 97 knees were identified. 29 studies reported on metallosis after TKA, 8 after UKA, and one study after both procedures. The time period between the primary implantation and metallosis emergence ranged between 6 weeks and 26 years. The most common reason was the failure of a metal-backed patellar component in 40%, followed by implant/structural- and PE failure (wear/dislocation) in 27% and 18% of the cases, respectively. Complete blood cell count, serum chemistry, erythrocyte sedimentation rate or C-reactive protein serum values were not indicative to diagnose metallosis. The diagnosis was confirmed by histopathological analyses and macroscopic evaluation during surgery. Depending on the particular cause various surgical procedures have been performed. Complete prosthesis exchange was the most common one showing no complications in 89.4% of the cases. Conclusions: Metallosis after knee arthroplasty is a rare and perhaps underestimated or under published complication. A systematic diagnostic approach is necessary for the timely and correct diagnosis. A thorough debridement as well as a (sub)total synovectomy should be always performed. In cases with a damaged component, a partial/complete prosthesis exchange leads to the best results. Should a malalignment be the cause of the metallosis, then it should be corrected within the revision surgery. [ABSTRACT FROM AUTHOR]

The good biocompatibility and corrosion resistance of the bulk CoCrMo alloy has resulted in it being used in the manufacture of implants and load bearing medical devices. These devices, however, can release wear and corrosion products which differ from the composition of the bulk CoCrMo alloy. The physicochemical characteristics of the particles and the associated in vivo reactivity are dictated by the wear mechanisms and electrochemical conditions at the sites of material loss. Debris released from CoCrMo hip bearings, taper junctions, or cement–stem interfaces can, therefore, have different chemical and morphological characteristics, which provide them with different in vivo toxicities. Here, we propose to assess and compare the characteristics of the particles released in vivo from CoCrMo tapers and cement–stem interfaces which have received less attention compared to debris originating from the hip bearings. The study uses state‐of‐art characterization techniques to provide a detailed understanding of the size, morphology, composition, and chemistry of the particles liberated from the wear and corrosion flakes from revised hip replacements, with an enzymatic treatment. The phase analyses identified Cr2O3 nanoparticles released from tapers and cement–stem interfaces, whose composition did not vary with origin or particle morphology. The size distributions showed significantly smaller particles were released from the stems, compared to the particles originating from the corresponding tapers. The investigation demonstrates that the tribocorrosive processes occurring at the taper and stem interfaces both result in Cr2O3 nanoparticle formation. [ABSTRACT FROM AUTHOR]

Determination of metals and trace elements in patients with total knee or hip arthroplasty with CoCrMo alloy was performed. Blood, urine and cerebrospinal fluid (CSF) samples were analyzed and compared with samples from healthy people. Levels of Co, Cr as well as Na, Ca, Fe, Zn, Se, Rb, Sb and Br were determined by means of neutron activation analysis. The values of Cr and Co of the blood and urine measurements were elevated in patients with replacement, and according to the statistical analysis, significant differences of the elements Zn, Br, Co and Sb were found in the CSF (p < 0.05). [ABSTRACT FROM AUTHOR]

Although we did not measure patient blood Co ion levels until this investigation, we believe that assuming pre-operative blood Co ion levels were within normal limits will not influence the outcome. References 1 He H, Zhang Z (2022) Letter to the editor: Blood cobalt ion level in patients with different sizes of cobalt/chrome femoral head with the Accolade TMZF stem. [Extracted from the article]

Wear particles generated by hip and knee arthroplasties disseminate to the liver and spleen with the highest concentrations observed in subjects who have had a failed arthroplasty. We asked to what extent metallic particles could also disseminate to remote hematopoietic bone marrow. Cored samples of red marrow from the axial skeleton and proximal humerus were obtained postmortem from four males and two females aged 79–92 years. Seven to seventeen years prior to their demise, each subject had undergone successful revision of their arthroplasty for mechanical failure in which an unintended wear condition had generated a large volume of metal particles. The marrow samples were analyzed using stained histological sections and energy dispersive X‐ray analysis. Intracellular metal alloy particles were detected in the bone marrow of the cranium, proximal humerus, sternum, ribs, lumbar vertebrae, and the iliac crest. The components previously revised for mechanical failure were confirmed to be the predominant source of the disseminated wear debris. Particles of either Ti, Ti6Al4V, CoCrMo, FeCrNi alloys, or BaSO4 were identified in 24 of the 25 marrow samples examined. The particles ranged in size from 50 nm (the limit of resolution of our technique) to 6 μm. Metallic wear particles generated by hip and knee arthroplasties can disseminate widely to hematopoietic bone marrow throughout the axial skeleton and proximal humerus, especially in cases with a history of severe wear. The hematopoietic microenvironment is potentially sensitive to metallic degradation products. However, actual medical sequelae from disseminated wear debris is a rare occurrence. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1930–1936, 2019. [ABSTRACT FROM AUTHOR]

Background: There is some uncertainty about the bearing to be used to substitute a broken ceramic. Using metal components (head or liner) may lead to catastrophic wear of the metal. Aim: The purpose of this article is to describe the long-term follow-up result of ceramic fracture replaced with metal-on-polyethylene (MoP). Methods: We report 3 cases of ceramic head fracture after ceramic-on-ceramic (CoC) total hip arthroplasty (THA) in which the broken ceramic was replaced with MoP. Results: All cases developed severe complications due to gross wear of the metal head: one developed a pseudotumour after a few months while the other 2 had significant local metallosis and toxic blood metal levels. Conclusions: When there is a fracture of a ceramic component, we advise caution with the use of metal heads, as small ceramic fragments can cause 3rd-body wear with massive metal debris and severe local and general complications. [ABSTRACT FROM AUTHOR]

We aimed to find a biomarker for patients with adverse reaction to metal debris (ARMD) due to a metal‐on‐metal (MoM) hip implant. First, we compared molecular markers of hypoxia‐inducible factor (HIF) pathway activation (BNIP3, GLUT1, HO1, VEGF, and HIF1A) and inflammatory response (IL1B and COX2) in tissue from patients undergoing revision of MoM hip implant with tissue from patients undergoing primary hip replacement (PHR). Second, we compared blood levels of the above molecular markers and additional inflammatory markers: TNFA, IL18, CASPASE1, NFKB or IKB, and TLR1–4 mRNA in patients with non‐failed MoM hips. We report the presence of increased expression of HIF‐target genes in the periprosthetic tissue in MoM patients when compared to the PHR group. This suggests HIF pathway activation due to MoM debris and the potential of using HIF targets as a predictor of failure. Analysis of blood samples from nonoverlapping, nonfailed, MoM group showed significantly higher expression of COX2 mRNA and significant correlations between HIF1A and GLUT1 mRNA expressions, and between HIF1A mRNA and selection of inflammatory genes, including IL18, IKB, TLR1, and TLR4. HIF pathway activation in the periprosthetic tissue biopsies of patients with hip replacements may represent the first biomarker to identify early ARMD. Further studies investigating blood biomarkers could also prove beneficial in detecting ARMD that could lead to an early intervention and improved patient outcome after hip revision surgery. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1352–1362, 2019. [ABSTRACT FROM AUTHOR]

Background: During the twentieth century, hip replacement became one of the most popular and successful operations. In the 1990s, a new type of hip replacement namely the metal‐on‐metal hip resurfacing was developed. This paper draws on one of the available implants, namely the DePuy Orthopaedics' Articular Surface Replacement (ASR) hip system which was withdrawn from the market because of higher than expected rates of failure. It examines media representations on the failure of the ASR metal‐on‐metal hip replacement device and its subsequent withdrawal from the market. Methods: Drawing on content analysis this paper explores how systemic failure of the medical implant was framed and performed by press media in the UK. Results: Two narratives were particularly important in framing press media coverage of the ASR case: the role of patients as passive recipients of care and a distinction between health and disability identities as related to how individuals' narratives about the past shaped their sense of present and future. In all cases, the voice of the orthopaedic surgeons responsible for the selection and implantation of the ASR devices remains silent. Conclusions: Press media coverage of medically induced harm in the UK is significantly less common than coverage of any other patient safety issues and public health debates. This study aims to contribute to the evidence base on how public discourse on medically induced harm becomes framed through the reported experiences of individuals in press media and also how this process influences the legitimacy of various solutions to medical errors or unanticipated outcomes. [ABSTRACT FROM AUTHOR]

Objective: To compare mid‐term clinical results of total hip arthroplasty (THA) with metal‐on‐metal (MoM) and metal‐on‐polyethylene (MoP) bearings and to evaluate the biological safety of the two kinds of prostheses. Methods: Thirty‐two patients who received a primary THA with an MoM articulation between January 2008 and December 2010 were selected to form the MoM group retrospectively. The MoP group consisted of 32 patients who received a THA with an MoP prosthesis during the same period. Clinical assessments, imaging examinations, laboratory tests, and metal ion concentration detections were conducted on each patient. Another 32 healthy volunteers were recruited as the control group. Results: Twenty‐seven patients in the MoM group and 28 patients in the MoP group completed the follow‐up, with a mean follow‐up time of 74.6 and 75.9 months, respectively. The mean Harris score at the latest follow‐up was 91.5 ± 5.1 in the MoM group versus 88.9 ± 4.0 in the MoP group (P = 0.22). The MoM group showed a better range of motion in flexion, abduction, and external rotation. Co and Cr levels in the MoM group were 2.5‐fold and 2.0‐fold of these in the MoP group. A mild change of liver function was observed in both groups, while the values of renal function and humoral immunity stayed static. Elevated proportions of Th1 and Th17 cells and decreased proportion of Th2 cells were observed in the MoM group. The occurrence rate of pseudotumors in the MoM and MoP groups was 40.74% ± 9.45% and 14.28% ± 6.61%, respectively (P < 0.05). Conclusion: At the mid‐term follow‐up, clinical results were satisfied in both groups. MoM prosthesis could result in elevated serum metal ion levels and there is a higher risk of pseudotumor. Long follow‐up is needed to evaluate the safety of MoM prostheses. [ABSTRACT FROM AUTHOR]

Hip implants have improved the mobility and quality of life in millions of individuals. This review presents the evolution of scientific knowledge regarding the history and understanding of systemic and local metal toxicological concerns of hip implants designs utilizing metal-on-metal (MoM) bearing surfaces used in hip resurfacing arthroplasty (HRA) and total hip arthroplasty (THA). This analysis addresses: (1) the history of the development of MoM hip implants; (2) the clinical and toxicological rationale for introducing second-generation MoM implants in the early 2000s as an alternative to metal-on-polyethylene bearings; (3) the subsequent history regarding success and failure of second-generation MoM devices; (4) a detailed review of the history of MoM toxicology, including carcinogenic potential, metal blood levels, hypersensitivity, and release of wear particles; and (5) a review of local tissue effects and MoM patient management. We have included an analysis of MoM THA and HRA survivorship trends aggregated from over 200 studies. By around 2008, HRA continued to be a challenging procedure with variable success rates, and concurrently, some THA devices began to experience higher than expected revision rates based on annual registry reports. The unexpected THA outcomes and continued challenges with HRA devices prompted many surgeons to question the role of toxicological effects in device performance. Regarding hypersensitivity, while conversion to metal sensitized status in some MoM patients occurs based on the skin patch or lymphocyte transformation testing, there is no evidence of a causal relationship between positive test results and device failure. The weight of evidence indicates that nanoparticles released from MoM implants are cleared from the local synovial space under normal wear conditions. The available data indicate that there are no discernible increases in local or systemic tumors following CoCr alloy implantation. Systemic health effects are rarely reported in MoM implant patients and are unlikely when blood concentrations are below 300 µg/L except when patients have specific risk factors. Over time, patient management evolved to include assays aimed at predicting implant function (blood monitoring) and soft tissue reactions (MRI and ultrasound imaging). Validation of these biomarkers as a diagnostic tool for implant function, patient pain, and, ultimately, implant survival, remains lacking. After the introduction of these biomarkers, differences in implant revision decisions emerged based on imaging abnormalities, increased serum metal ion levels, and overall clinical presentation. Discrepancies in patient management algorithms and the lack of consensus in local biological effects terminology have contributed to variability in reporting incidence, etiology, and dose effects on local tissue responses in MoM implants. This variability has contributed to a debate regarding the benefit or risk of revising asymptomatic patients. Therefore, while toxicological assessments of normal functioning MoM implants indicate that MoM implants are relatively safe because of low wear and clearance of metal, more analysis of revision data is needed in order to best inform patient management decisions, particularly for asymptomatic patients, as well as patients with minor symptoms under consideration for conservative pain management treatments. [ABSTRACT FROM AUTHOR]

The occurrence of pseudotumors currently constitutes an important topic of interest among orthopaedic surgeons who prefer metal on metal arthroplasty and especially hip resurfacing arthroplasty. Adverse reactions to metal ions are associated with the formation of such lesions and the orientation of implants has also been implicated in their pathogenesis. The diagnosis of pseudotumors is as difficult as complex. There is a variety of symptoms and patients with mild or tolerable pain may not seek medical attention. Revision surgeries may be the only solution in some cases. The goal of this article is to review the clinical presentation, prognosis of pseudotumors and associated complications, based on evidence published in the literature. [ABSTRACT FROM AUTHOR]

Over 300,000 hip replacements occurred in the USA in 2010, and the frequency is likely increasing annually. Blood Cobalt (Co) concentrations in patients with well-functioning cobalt-chromium (Co-Cr) hip implants are usually elevated above background concentrations relative to the general population. Excessive Co exposure, in rare cases, can result in cardiomyopathy. The purpose of this review was to identify cases of cardiomyopathy in metal-containing hip implant patients and to evaluate the possible cause of each patient’s cardiomyopathy. We evaluated 15 cases published between 2009 and 2016, and, based on a review of the preexisting risk factors, blood Co concentrations, and histopathological information published for each patient, they were stratified into one of four categories regarding the association between Co exposure and the development of cardiomyopathy: (1) Co was causal (five cases); (2) Co was contributory (two cases); (3) Co was possibly contributory (six cases); and (4) Co was non-causal (two cases). In all 15 cases, blood Co concentrations (14-6521 μg/L) were elevated beyond levels associated with the majority of metal-containing implant patients (0.1-10 μg/L), and, in many cases, there was evidence of a malfunctioning implant. The data indicate that individuals with well-functioning implants, even those with preexisting risk factors, are at no risk of developing cardiac effects. We conclude that blood Co measurements are informative, but should be interpreted with caution, and in context of other factors evaluated in this analysis. The mere presence of elevated Co is not sufficient to indicate causation for a patient’s cardiomyopathy. [ABSTRACT FROM AUTHOR]

Background and purpose — The initial outcomes following metal-on-metal hip arthroplasty (MoMHA) revision surgery performed for adverse reactions to metal debris (ARMD) were poor. Furthermore, robust thresholds for performing ARMD revision are lacking. This article is the second of 2. The first article considered the various investigative modalities used during MoMHA patient surveillance (Matharu et al. 2018a). The present article aims to provide a clinical update regarding ARMD revision surgery in MoMHA patients (hip resurfacing and large-diameter MoM total hip arthroplasty), with specific focus on the threshold for performing ARMD revision, the surgical strategy, and the outcomes following revision. Results and interpretation — The outcomes following ARMD revision surgery appear to have improved with time for several reasons, among them the introduction of regular patient surveillance and lowering of the threshold for performing revision. Furthermore, registry data suggest that outcomes following ARMD revision are influenced by modifiable factors (type of revision procedure and bearing surface implanted), meaning surgeons could potentially reduce failure rates. However, additional large multi-center studies are needed to develop robust thresholds for performing ARMD revision surgery, which will guide surgeons’ treatment of MoMHA patients. The long-term systemic effects of metal ion exposure in patients with these implants must also be investigated, which will help establish whether there are any systemic reasons to recommend revision of MoMHAs [ABSTRACT FROM AUTHOR]

Introduction: The purpose of the present study is to report the long-term clinical results of an uncemented total hip arthroplasty (THA) using a Metasul metal-on-metal (MoM) 28-mm bearing and to evaluate the long-term serum cobalt levels. Methods: At an average of 12.6 years following primary THA, we retrospectively reviewed the clinical results of the first 116 consecutive patients (128 THAs) in our institution who underwent 28-mm Metasul MoM THA. Of the 78 patients who were able to visit our outpatient clinic, serum cobalt levels were evaluated. Results: The overall survival rate of the cohort was 96.1% (95% confidence interval [CI], 93.2-99.6), 12.6 years (95% CI, 12.3-12.7 years) following surgery. 3 patients had undergone revision due to aseptic loosening of the stem and 2 patients sustained a periprosthetic fracture. The average modified Harris Hip Score was 90 (72-97) and the average Oxford Hip Score was 56 (48-60), representing both excellent outcome scores. The average serum cobalt of the entire cohort was 20.1 nmol/L (range 8.5-227.7 nmol/L). Serum cobalt levels of patients with a bilateral MoM THA were significantly higher (35.0 nmol/l, p<0.01). No relation between serum cobalt levels, subjective outcome, radiolucent lines on radiographs and survivorship of the implant was noted. Conclusions: Long-term results of the metasul MoM bearing articulation in THA seem to be excellent, although cobalt serum levels should be monitored closely. [ABSTRACT FROM AUTHOR]

Most adverse events following total hip arthroplasty (THA) are uncommon and preventable or treated easily as expected. Adverse effects related to any major surgical procedure, including anesthesia, performing with other medical problems, drugs, and allergic reactions, might also occur. Potential cardiovascular complications are known to occur during or following THA and will be reviewed here. Complications can be categorized as myocardial infarction, cardiac arrest, thromboembolism, and so on. Special considerations in cardiovascular procedures are also reviewed in this paper. [ABSTRACT FROM AUTHOR]

Metals and metal alloys are the most used materials in orthopedic implants. The focus is on total hip arthroplasty (THA) that, though well tolerated, may be associated with local and remote adverse effects in the medium-long term. This review aims to summarize data on the biological consequences of the metal implant degradation that have been attributed predominantly to metal-on-metal (MoM) THA. Local responses to metals consist of a broad clinical spectrum ranging from small asymptomatic tissue lesions to severe destruction of bone and soft tissues, which are designated as metallosis, adverse reactions to metal debris (ARMD), aseptic lymphocytic vasculitis associated lesion (ALVAL), and pseudotumors. In addition, the dissemination of metal particles and ions throughout the body has been associated with systemic adverse effects, including organ toxicity, cancerogenesis, teratogenicity, and immunotoxicity. As proved by the multitude of studies in this field, metal degradation may increase safety issues associated with THA, especially with MoM hip systems. Data collection regarding local, systemic and long-term effects plays an essential role to better define any safety risks and to generate scientifically based recommendations. [ABSTRACT FROM PUBLISHER]

A letter to the editor is presented in response to the article "Results of Revision of Total Hip Arthroplasty for Alumina Ceramic-on-Ceramic Bearing Fracture" by R. Trebse et al. in a 2016 issue.