Fatal cardiomyopathy after revision total hip replacement for fracture of a ceramic liner

Elevated neurofilament light chain associated with cobalt/chromium metal neurotoxicity in a patient with a failed hip implant

BACKGROUND

It is known that the heavy metals cobalt and chromium are associated with neurotoxicity. Chromium (Cr) and Cobalt (Co) are both components of metal-on-metal (MoM) implants which can be degraded/fragmented and released into the bloodstream. Neurofilament Light Chain (NfL) is a neuron-specific protein that increases in serum following axonal damage. Here, we report a novel case of a patient with neurotoxic concentrations of serum Co and Cr stemming from fragments of a Metal on Metal (MoM) hip implant exhibiting elevated serum NfL concentrations.

CASE PRESENTATION

A 56-year-old female patient with ceramic and metal fragments left in her body after hip arthroplasty revision presented with symptoms consistent with Co/Cr neurotoxicity. Serum Co, Cr and NfL concentrations were measured to assess metal ion exposure and its potential link to her neurological symptoms. Over four months following two revision surgeries, her serum Co and Cr concentrations decreased significantly from their peak levels, along with a concomitant decrease in NfL concentrations. During this period, the patient's pathological neurological symptoms gradually resolved, with serum Co, Cr, and NfL concentrations approaching normal ranges.

CONCLUSION

Serum NfL is elevated in a patient exhibiting neurotoxicity from Co/Cr implant exposure. The potential utility of serum NfL as a biomarker for metal associated neurotoxicity should be further explored.

Comprehensive review on toxic heavy metals in the aquatic system: sources, identification, treatment strategies, and health risk assessment

Heavy metal pollution in water sources has become a major worldwide environmental issue, posing a threat to aquatic ecosystems and human health. The pollution of the aquatic environment is increasing as a result of industrialization, climate change, and urban development. The sources of heavy metal pollution in water include mining waste, leachates from landfills, municipal and industrial wastewater, urban runoff, and natural events such as volcanism, weathering, and rock abrasion. Heavy metal ions are toxic and potentially carcinogenic. They can also buildup in biological systems and cause bioaccumulation even at low levels of exposure, heavy metals can cause harm to organs such as the nervous system, liver and lungs, kidneys and stomach, skin, and reproductive systems. There were various approaches tried to purify water and maintain water quality. The main purpose of this article was to investigate the occurrence and fate of the dangerous contaminants (Heavy metal and metalloids) found in domestic and industrial effluents. This effluent mixes with other water streams and is used for agricultural activities and other domestic activities further complicating the issue. It also discussed conventional and non-conventional treatment methods for heavy metals from aquatic environments. Conclusively, a pollution assessment of heavy metals and a human health risk assessment of heavy metals in water resources have been explained. In addition, there have been efforts to focus on heavy metal sequestration from industrial waste streams and to create a scientific framework for reducing heavy metal discharges into the aquatic environment.

Prosthetic Metals: Release, Metabolism and Toxicity

The development of metallic joint prostheses has been ongoing for more than a century alongside advancements in hip and knee arthroplasty. Among the materials utilized, the Cobalt-Chromium-Molybdenum (Co-Cr-Mo) and Titanium-Aluminum-Vanadium (Ti-Al-V) alloys are predominant in joint prosthesis construction, predominantly due to their commendable biocompatibility, mechanical strength, and corrosion resistance. Nonetheless, over time, the physical wear, electrochemical corrosion, and inflammation induced by these alloys that occur post-implantation can cause the release of various metallic components. The released metals can then flow and metabolize in vivo, subsequently causing potential local or systemic harm. This review first details joint prosthesis development and acknowledges the release of prosthetic metals. Second, we outline the metallic concentration, biodistribution, and elimination pathways of the released prosthetic metals. Lastly, we discuss the possible organ, cellular, critical biomolecules, and significant signaling pathway toxicities and adverse effects that arise from exposure to these metals.

Investigation of cell-accelerated corrosion (CAC) on the CoCrMo alloy with segregation banding: Hip implant applications

Metal alloy microstructure plays a crucial role in corrosion associated with total hip replacement (THR). THR is a prominent strategy that uses metal implants such as cobalt-chromium-molybdenum (CoCrMo) alloys due to their advantageous biological and mechanical properties. Despite all benefits, these implants undergo corrosion and wear processes in-vivo in a synergistic manner called tribocorrosion. Also, the implant retrieval findings reported that fretting corrosion occurred in-vivo, evidenced by the damage patterns that appeared on the THR junction interfaces. There is no scientific data on the studies reporting the fretting corrosion patterns of CoCrMo microstructures in the presence of specific biological treatments to date. In the current study, Flat-on-flat fretting corrosion set-up was customized and used to study the tribocorrosion patterns of fretting corrosion to understand the role of alloy microstructure. Alloy microstructural differences were created with the implant stock metal's longitudinal and transverse cutting orientations. As a result, the transverse created the non-banded, homogenous microstructure, whereas the longitudinal cut resulted in the banded, non-homogenous microstructure on the surface of the alloy (in this manuscript, the terms homogenous and banded were used). The induced currents were monitored using a three-electrode system. Three different types of electrolytes were utilized to study the fretting corrosion patterns with both homogeneous and banded microstructures: 1. Control media 2. Spent media (the macrophage cell cultured media) 3. Challenged media (media collected after the macrophage was treated with CoCrMo particles). From the electrochemical results, in the potentiostat conditions, the banded group exhibited a higher induced current in both challenged and spent electrolyte environments than in control due to the synergistic activity of CoCrMo particles and macrophage demonstrating more corrosion loss. Additionally, both Bode and Nyquist plots reported a clear difference between the banded and homogeneous microstructure, especially with challenged electrolytes becoming more corrosion-resistant post-fretting than pre-fretting results. The banded microstructure showed a unique shape of the fretting loop, which may be due to tribochemical reactions. Therefore, from the electrochemical, mechanical, and surface analysis data results, the transverse/homogenous/non-banded alloy microstructure groups show a higher resistance to fretting-corrosion damage.

Ceramic-on-Ceramic or Metal-on-Polyethylene: The Bearing of Choice after Ceramic Component Fracture in Total Hip Arthroplasty along with Concise Follow-Up of the Previous Cohort

OBJECTIVE

We previously reported the questionable result of reoperation using metal-on-polyethylene (MoP) bearing after the fracture of the ceramic component. After the report, we abandoned the use of MoP; instead, we used ceramic-on-ceramic (CoC) bearing. This report aimed to present the outcome of reoperation to CoC bearing after ceramic component failures along with the longer-term outcome of the previously reported cohort with an MoP bearing.

RESULTS

The mean follow-up of the MoP cohort was extended from 4.3 years to 8.8 years. Metallosis had occurred in three of nine patients of the previous cohort, which all required re-reoperations. Two hips from 11 patients with revision to CoC had re-reoperations due to ceramic liner fracture and non-union of the osteotomized fragment, respectively. No metallosis and wear occurred in the cohort revised with CoC articulation. Otherwise, there were no adverse changes in radiographs and no impairment in functions.

METHODS

We conducted an extended prospective evaluation of a previous cohort consisting of six head fractures and three liner fractures. In this cohort, the patients underwent a bearing change to metal-on-polyethylene. Additionally, we retrospectively analyzed 11 cases of third-generation ceramic bearing fractures, comprising nine head fractures and two liner fractures. These cases were subsequently treated with a bearing change to fourth-generation CoC. We assessed clinical and radiological outcomes, including complication rates, in both groups.

CONCLUSION

We recommend the latest CoC as the bearing of choice in reoperation after the fracture of ceramic components. In the case of an MoP bearing after the ceramic component fracture, the risk of metallosis seemed high in the early postoperative period.

Explant analysis of a Discocerv cervical disc: A case study for a ceramic-on-ceramic cervical disc

Explant analyses are key to better understanding the effectiveness of medical implants in replacing natural joints. For the first time, an explanted Discocerv cervical disc was examined. The implant utilised the articulation of a caudal zirconia cup (inferior component) and a cephalic alumina head (superior component). The articulating surface of the superior alumina head had an average surface roughness of 0.016 ± 0.003 μm (Sa) and the articulating surface of the inferior zirconia cup had an average surface roughness of 0.015 ± 0.002 μm (Sa). Both articulating surfaces had negative skewness, indicating the removal of local peaks. The difference between the average surface roughness of the components was not significant (p-value: 0.741). Dark grey marks were observed on both of the articulating surfaces, which were found to be adhered titanium debris that was generated due to component impingement. This titanium debris may explain the small amount of metallosis that was reported at explantation. Some transfer of zirconium to the alumina articulating surface was also seen.

Microstructural Evolution, Mechanical Properties, and Preosteoblast Cell Response of a Post-Processing-Treated TNT5Zr β Ti Alloy Manufactured via Selective Laser Melting

A Ti–34Nb–13Ta–5Zr (TNT5Zr) β Ti alloy with a high strength-to-modulus ratio has been developed, showing its potential to become another candidate material in load-bearing implant applications. This work mainly investigates the microstructural evolution, mechanical properties, and biocompatibility of a post-processing-treated TNT5Zr alloy manufactured via selective laser melting (SLM). Transmission electron microscopy observation shows the existence of the single beta grain matrix and alpha precipitates along the grain boundary in the SLM + HIP manufactured TNT5Zr alloy (TNT5Zr-AF + HIP), and ellipsoidal nano-sized intragranular α″ precipitates (approx. 5–10 nm) were introduced after the subsequent low-temperature aging treatment. The precipitation strengthening enables the SLM + HIP + aging manufactured TNT5Zr (TNT5Zr-AF + HIPA) alloy to show a comparable ultimate tensile strength (853 ± 9 MPa) to that of the reference material (Ti64-AF + HIP, 926 ± 23 MPa). Including the inferior notch-like surface of the test pieces, the slip-band cracking that occurs in this ductile TNT5Zr-AF + HIPA alloy is regarded as the main factor in determining its fatigue strength (170 MPa). In vitro short-term biocompatibility evaluation reveals almost no significant difference in the preosteoblast viability, differentiation, and mineralization between TNT5Zr-AF + HIPA and the reference biomaterial (Ti64-AF + HIP).

Cobalt Neurotoxicity: Transcriptional Effect of Elevated Cobalt Blood Levels in the Rodent Brain

Metal-on-metal (MoM) hip implants made of cobalt chromium (CoCr) alloy have shown early failure compared with other bearing materials. A consequence of the abnormal wear produced by these prostheses is elevated levels of cobalt in the blood of patients, which can lead to systemic conditions involving cardiac and neurological symptoms. In order to better understand the implications for patients with these implants, we carried out metal content and RNA-Seq analysis of excised tissue from rats treated intraperitonially for 28 days with low concentrations of cobalt. Cobalt blood levels in dosed rats were found to be similar to those seen in some patients with MoM implants (range: 4–38 μg/L Co in blood). Significant accumulation of cobalt was measured in a range of tissues including kidney, liver, and heart, but also in brain tissue. RNA-Seq analysis of neural tissue revealed that exposure to cobalt induces a transcriptional response in the prefrontal cortex (pref. cortex), cerebellum, and hippocampus. Many of the most up- and downregulated genes appear to correspond to choroid plexus transcripts. These results indicate that the choroid plexus could be the brain tissue most affected by cobalt. More specifically, the differentially expressed genes show a disruption of steroidogenesis and lipid metabolism. Several other transcripts also demonstrate that cobalt induces an immune response. In summary, cobalt exposure induces alterations in the brain transcriptome, more specifically, the choroid plexus, which is in direct contact with neurotoxicants at the blood–cerebrospinal fluid barrier.

Self-Reported Neurotoxic Symptoms in Hip Arthroplasty Patients With Highly Elevated Blood Cobalt: A Case-Control Study

OBJECTIVES

This study aimed to investigate the prevalence of self-reported neurotoxicity and cognitive defects in hip replacement patients with markedly raised blood cobalt.

METHODS

Case group comprised 53 patients with metal-on-metal (MoM) implants and a history of blood Co ≥20 μg/L for a median of 3 years (interquartile range, 2-5 years). The control group comprised 53 patients with ceramic-on-ceramic prostheses and blood Co <1 μg/L. Median age was 67 years (interquartile range, 60-74 years). The participants completed the Neurotoxic Symptom Checklist-60, Diabetic Neuropathy Score, Douleur Neuropathique-10, and Systemic Symptom Checklist, and underwent the Mini-Mental State Examination.

RESULTS

The MoM and ceramic-on-ceramic groups were compared, the results were as follows: Neurotoxic Symptom Checklist-60 (median): cognitive defects (2.0 versus 1.9; P = 0.002), chest complaints (1.3 versus 1.3; P = 0.042), balance disturbances (1.3 versus 1.0; P < 0.001), sleep disturbances (2.7 versus 2.0; P = 0.004), mood disorders (2.0 versus 1.5; P = 0.001), sensorimotor disorders (1.6 versus 1.2; P < 0.001), physical complaints (2.0 versus 1.4; P = 0.009), fatigue (2.0 versus 1.6; P = 0.001), and total score (108 versus 90; P < 0.001); abnormal Diabetic Neuropathy Score/Douleur Neuropathique-10 (%): 60.3/13.2 versus 24.5/1.9 (P < 0.001/P = 0.028). Systemic Symptom Checklist (in percent): feeling cold (37.7 versus 17; P = 0.01), weight gain (18.9 versus 1.9; P = 0.008), metallic taste (26.4 versus 3.8; P = 0.002), worsening eyesight (37.7 versus 15.1; P = 0.008) and hearing (24.5 versus 7.5; 0.032), ankle swelling (32.1 versus 7.5; P = 0.002), shortness of breath on exertion (9.4 versus 5.7; P = 0.015), and generalized rash (28.3 versus 7.5; P = 0.01); and Mini-Mental State Examination (median): 29 versus 30 (P = 0.017). Patients in the MoM group were aware of their high cobalt levels and displayed a higher tendency to overreport symptoms (P < 0.001), which could have contributed to the higher scores.

CONCLUSIONS

Frequency of reporting a number of symptoms was markedly higher in MoM patients, but clinically significant neurotoxicity was not observed (possibly due to the short exposure to elevated cobalt). Patients with repeated blood Co ≥20 μg/L measurements should be questioned about possible systemic health complaints at follow-up.

Metallosis in Sequelae of Prosthetic Revision for Ceramic Components Fracture: A Case Report with Clinical Presentation Mimicking Periprosthetic Hip Infection

Ceramic on ceramic total hip arthroplasties have been developed and widely used during last decades because of their long-term survival and biomechanical properties. One of the most dangerous complication of these implants is the fracture of the ceramic components. The management of this condition should be carefully planned and the choice of the new implant is crucial. We describe a rare case of severe hip synovitis due to massive metallosis in sequelae of mismanaged prosthetic revision for fracture of the ceramic acetabular liner with an unusual clinical presentation that simulate a periprosthetic infection.

Cobalt-induced cardiomyopathy - do circulating cobalt levels matter?

Elevated levels of circulating cobalt ions have been linked with a wide range of systemic complications including neurological, endocrine, and cardiovascular symptoms. Case reports of patients with elevated blood cobalt ions have described significant cardiovascular complications including cardiomyopathy. However, correlation between the actual level of circulating cobalt and extent of cardiovascular injury has not previously been performed. This review examines evidence from the literature for a link between elevated blood cobalt levels secondary to metal-on-metal (MoM) hip arthroplasties and cardiomyopathy. Correlation between low, moderate, and high blood cobalt with cardiovascular complications has been considered. Elevated blood cobalt at levels over 250 µg/l have been shown to be a risk factor for developing systemic complications and published case reports document cardiomyopathy, cardiac transplantation, and death in patients with severely elevated blood cobalt ions. However, it is not clear that there is a hard cut-off value and cardiac dysfunction may occur at lower levels. Clinical and laboratory research has found conflicting evidence of cobalt-induced cardiomyopathy in patients with MoM hips. Further work needs to be done to clarify the link between severely elevated blood cobalt ions and cardiomyopathy.

Cite this article: Bone Joint Res 2021;10(6):340–347.

BLOOD CHROMIUM-COBALT LEVELS IN PATIENTS AFTER TOTAL KNEE ARTHROPLASTY AND THEIR EFFECT ON THE RETINAL NERVE FIBER LAYER AND MACULAR GANGLION CELL COMPLEX

PURPOSE

To study blood cobalt (Co) and chromium (Cr) levels in patients who have undergone total knee arthroplasty and their effect on the retinal nerve fiber layer and macular ganglion cell complex.

METHODS

One hundred patients who had undergone total knee arthroplasty and 50 healthy individuals who had no implants were included in the study. The patients were separated into two groups based on how long ago the prosthesis had been implanted (Group 1: 1 to 5 years; Group 2: 5 to 10 years). After a complete ophthalmological examination, retinal nerve fiber layer and macular ganglion cell complex of the patients were evaluated with optical coherence tomography, performed on dilated pupils. To assess the metal ion levels of the patients, venous blood samples were drawn from each patient.

RESULTS

The mean age of the patients was 64.72 ± 6.26 years in Group 1, 67.80 ± 8.07 years in Group 2, and 63.42 ± 7.90 years in the control group. In the comparison of age and sex, there were no statistically significant differences between the groups and the control group. Co and Cr levels were statistically higher in Group 1 and Group 2 compared with the control group (P < 0.001). Mean retinal nerve fiber layer thicknesses and mean macular ganglion cell complex thicknesses in Group 1 and Group 2 were statistically lower than in the control group.

CONCLUSION

Levels of Co and Cr are higher in patients who undergone total knee arthroplasty than healthy subjects, and these higher levels were associated with changes in the retinal nerve fiber layer and macular ganglion cell complex.

A case report of cobalt cardiomyopathy leading to electric storm and cardiogenic shock: the importance of the orthopaedic background in patients with heart failure of unknown aetiology

Background 

The first series of cobalt cardiomyopathy was described in the 60s in relation to the abuse of a cobalt containing beer. Since then, millions of metal hip arthroplasties have been performed and a small number of cobalt cardiomyopathies related to metal prosthesis have been reported.

Case summary 

We report a case of a 48-year-old man who developed a severe non-dilated restrictive cardiomyopathy in the setting of a systemic metallosis following several hip arthroplasties. The diagnosis was suspected by exclusion of other more common causes for restrictive cardiomyopathies and confirmed by the levels of cobalt and chromium in the serum and the endomyocardial biopsy performance that showed metal deposits in myocardial tissue. Despite the removal of the metal prosthesis and a significant decrease in serum metal levels, he suffered cardiogenic shock (CS) and electric storm that required emergency mechanical circulatory support as a bridge to heart transplant.

Discussion 

Cobalt cardiomyopathy is a rare condition that has been observed in patients who develop cobalt toxicity after metal hip arthroplasty. The condition may improve after diagnosis and removal of the prosthesis or get worse and progress to end-stage heart failure or CS. The concern about the metal toxicity associated with metal hip prosthesis has increased in the last few years. Orthopaedic surgeons and cardiologists should be aware of this severe complication that is probably under diagnosed.

Cobalt-related cardiomyopathy: A real concern! A review of published evidence

BACKGROUND

Cobalt (Co) toxicity-related cardiomyopathy (CMP) in hip arthroplasty has recently been reported in the literature. The purpose of this review was to identify and assess available published evidence of CMP in hip arthroplasty patients and to derive recommendations for management.

METHODS

We evaluated 23 cases reported till October 2018 and stratified into three categories, based on pre-existing risk factors for CMP, histological confirmation and evidence of systemic signs of Co toxicity.

RESULTS

Co toxicity was considered to be the definite cause of CMP in 8 cases and probably contributory in 13 cases. Two cases were considered to have developed CMP secondary to pre-existing risk factors. Majority of the patients had good recovery of cardiac function after hip revision and cardiac management, but five cases deteriorated and died.

CONCLUSION

Although Co-related CMP has been reported in a small number of cases of hip arthroplasty, a delay or missed diagnosis may lead to significant morbidity and mortality. Timely diagnosis, removal of causative implant and avoidance of metal articulations in revision for fractured ceramic implants may help in effective management.

Pushing Ceramic-on-Ceramic in the most extreme wear conditions: A hip simulator study

BACKGROUND

Hip revision surgery for fractured ceramic components may represent the worst-case wear scenario due to the high risks of recurrent dislocations, instability, and third body wear. The ideal bearing choice for the new prosthetic articulation is still subject of debate, while alumina matrix composite (AMC) articulations offer theoretical superior performances; the present work was designed to test the wear behaviour of ceramic on ceramic articulations (liner and head) in a worst-case scenario by adding ceramic third-body particles to the test lubricant with combined walking and subluxation cycles in a hip joint simulator. Therefore, we performed an in vitro study aiming to assess how does AMC articulation perform with 1) third-body particles added to the test environment and 2) under subluxation stresses.

HYPOTHESIS

We hypothesised that AMC articulations offer superior performances in such worst conditions.

MATERIALS AND METHODS

A hip simulator test was designed to analyse how AMC articulation performs with third-body particles added to the test environment and under subluxation stresses. Two different load patterns including level walking and subluxation of the ceramic liner were applied. The test fluid lubricant was contaminated by adding coarse ceramic particles during the first 2 million cycles and fine ceramic particles from 2 to 4 million cycles. Group 1 consisted of an alumina matrix composite articulation (liner and head); group 2 consisted of an alumina liner and an alumina matrix composite head. A control group consisting of an alumina ceramic liner articulated against an alumina matrix composite head was provided and only axially loaded. The liners of groups 1 and 2 were tested at an in vivo angle of 45° in the medial lateral plane (inclinationangle), which corresponds to an angle L=30° relative to the ISO standard fixated position used for in vitro testing. All mass measurements were performed using a high precision balance (Sartorius BP211D). During each examination, images on dedicated location of the bearing surfaces were taken using a digital microscope.

RESULTS

Mean cumulative wear of 0.09mg per million cycles between 2 and 4 million cycles was detected in group 2, and this value was significantly lower (p=0.016) in comparison with the average value in group 1 (0.21mg per million cycle). This result can be explained in light of a possible transformation phase of zirconia in AMC liners, probably due to excessive stress during subluxation cycles. However, wear levels observed are close to the gravimetric measurement detection limit of the Sartorious Balance (about 0.1-0.2mg); therefore, wear can be considered negligible in all groups.

CONCLUSION

Our results confirm that AMC couplings perform very well even in the worst-case wear scenario. Since AMC articulations revealed 25% lower cumulative wear respect to AMC on cross linked polyethylene in same simulator setup, AMC articulations should be considered the bearing of choice in revision surgery in light of the high risk of recurrent dislocations, instability, and third body wear.

LEVEL OF EVIDENCE

III, prospective case-control study, in vitro.

Bowing-head sign: rare but detectable in pre-catastrophic hip implant failure

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.

Echocardiographic Changes in the Context of Metal-on-Metal Versus Nonmetal-on-Metal Total Hip Arthroplasty

BACKGROUND

The purpose of this study is to determine if there is a difference in echocardiographic results between patients with metal-on-metal (MoM) vs non-MoM total hip arthroplasty (THA) and to determine if a correlation exists between serum metal levels and echocardiographic outcomes.

METHODS

Seventy-five patients with the same modular THA enrolled in this prospective cohort study, and 49 had MoM bearings. All patients had serum cobalt, chromium, and titanium levels drawn at 2 study visits with a transthoracic echocardiogram at the second visit. Serum metal concentrations and echocardiographic parameters were compared with 2-way t-tests. Multiple linear regression analyses identified any significant predictors of echocardiographic outcomes.

RESULTS

Mean serum cobalt and chromium levels were significantly greater in the MoM group at both time-points (P < .001 and P < .05, respectively). Titanium levels were similar between groups (P > .05). MoM patients had significantly lower global longitudinal strain compared with the non-MoM group (18.4% vs 20.2%; P = .026). Serum cobalt concentration was found to be an independent predictor of tricuspid annular plane systolic excursion (P = .02).

CONCLUSION

MoM THA bearings are associated with increased serum cobalt and chromium levels. Patients with MoM THAs had decreased global longitudinal strain, a measure of left ventricular function, but both groups remained within normal range. The clinical impact of the positive association between serum cobalt concentration and tricuspid annular plane systolic excursion, a marker of right ventricular function, deserves further study. These findings can reassure physicians and patients that metal-induced cardiomyopathy is not typical in the setting of MoM THA.

LEVEL OF EVIDENCE

Level II, Prospective Cohort Study.

Delayed-type Hypersensitivity to Metals in Newly Diagnosed Patients with Nonischemic Dilated Cardiomyopathy

The causes of nonischemic dilated cardiomyopathy are classified as genetic or nongenetic, but environmental factors such as metal pollutants may interact with genetic susceptibility. The presence of metal particles has been detected in the myocardium, including in those patients with dilated cardiomyopathy. It is also known that hypersensitivity reactions can induce inflammation in tissue. The present study aimed to verify if metal-induced delayed-type hypersensitivity is present in patients with nonischemic dilated cardiomyopathy. The patient group consisted of 30 patients with newly diagnosed dilated cardiomyopathy; the control group comprised 41 healthy subjects. All patients and control subjects provided blood samples for lymphocyte transformation testing (MELISA®) to assess possible hypersensitivity to seven common metals. Specific exposure to metals was based on interview data. Results showed that exposure to cadmium and lead (p = 0.0002), aluminum (p = 0.0006), nickel (p = 0.0012), and chromium (p = 0.0065) was more often reported by patients than controls. The patients also had significantly more frequent hypersensitivity reactions to mercury (26.7% vs. 7.3%, p = 0.014624), nickel (40% vs. 12.2%, p = 0.02341), and silver (20% vs. 4.8%, p = 0.025468) than the control group. Patients with dilated cardiomyopathy had greater exposure to certain metals compared with healthy controls. Hypersensitivity to metals was more frequent in patients with dilated cardiomyopathy, suggesting a possible association that warrants further investigation.

Comparison of Harris Hip Scores and Revision Rates in Metal-on-Metal Versus Non-Metal-on-Metal Total Hip Arthroplasty

INTRODUCTION

This study compares functional outcome scores and revision rates between metal-on-metal (MoM) and non-MoM total hip arthroplasty patients.

METHODS

A cohort of 75 patients who underwent implantation of the same dual modular hip arthroplasty between the years of 2004 and 2010 was enrolled. Patients were subsequently evaluated in 2015 to 2017 for joint revision history and functionality, as measured by the Harris hip score (HHS). Patients requiring a revision arthroplasty were not included in the HHS analysis.

RESULTS

A total of 49 patients had MoM implants (65.3%), and 26 patients had non-MoM implants (34.8%). At a mean follow-up of 7.6 years, 10.2% (5/49) of MoM prostheses required revision, whereas 3.8% (1/26) of non-MoM prostheses required revision (P = 0.334). The mean HHS in the MoM cohort was 89.8, compared with 88.1 in the non-MoM cohort (P = 0.69).

CONCLUSION

HHSs were not notably different between cohorts. The MoM cohort had three times as many revisions as the non-MoM cohort, but given the numbers available, this difference did not reach significance. Given the clinical importance of these revision data, further study is warranted to determine survivorship of the MoM versus non-MoM total hip arthroplasty at long-term follow-up.

A Systematic Review of Systemic Cobaltism After Wear or Corrosion of Chrome-Cobalt Hip Implants

Objectives

We sought to synthesize data on systemic arthroprosthetic cobaltism, a recently described syndrome that results from wear or corrosion of chrome-cobalt hip components.

Methods

We conducted a systematic literature review to identify all reported cases of systemic arthroprosthetic cobaltism. To assess the epidemiologic link between blood cobalt levels (B[Co]), we developed a symptom scoring tool that evaluated 9 different symptom categories and a category of medical utilization.

Results

We identified 25 patients reported between 2001 and 2014 with a substantial increase in case reports over the past 3 years. Symptoms were diverse and involved the hip (84%), cardiovascular system (60%), audiovestibular system (52%), peripheral motor-sensory system (48%), thyroid (48%), psychological functioning (32%), visual system (32%), and the hematological, oncological, or immune system (20%). The mean latency from implantation to presentation or revision was 41 months (range, 9–99 months). The mean B[Co] was 324 μg/L and 4 patients had levels less than 20 μg/L. The B[Co] but not blood chromium level was highly associated with a quantitative measure of overall symptom severity (r², 0.81; P < 0.001). Mean B[Co] and symptom scores were substantially higher in patients with revisions of failed ceramic-on-ceramic prostheses than those with primary metal-on-metal prostheses.

Conclusions

Systemic arthroprosthetic cobaltism is an increasingly recognized complication of wear or corrosion of chrome-cobalt hip implants, may involve a large number of organ systems, and may occur with relatively low B[Co]. There is an urgent need to better define the overall scope of the problem and to develop screening and management strategies.

Postmortem Retrieval Analysis of Metallosis and Periprosthetic Tissue Metal Concentrations in Total Knee Arthroplasty

BACKGROUND

The purpose of this study is to determine the preferred sampling location for tissue analysis in total knee arthroplasty (TKA) and to evaluate metal concentrations, inflammatory cytokines, component damage, and tissue metallosis.

METHODS

Twenty TKA systems were collected at necropsy along with tissue samples from 5 distinct locations. Inductively coupled plasma mass spectrometry (ICP-MS) analysis was performed to determine cobalt (Co), chromium (Cr), and titanium (Ti) concentrations. Synovial fluid cytokine analysis was preformed using a Magnetic Luminex Screening Assay. Femoral components were assesed for damage and tissues were visually scored for metallosis.

RESULTS

The median metal concentrations were 16 ppb for Co, 46 ppb for Cr, and 9.8 ppb for Ti. There was no association between the tissue collection site and the metal concentration for Co (P = .979), Cr (P = .712), or Ti (P = .854). Twelve of 20 of the necropsy-retrieved TKAs had metallosis, but there was no correlation between Co (P = .48), Cr (P = .89), or Ti (P = .60) concentration and metallosis. Increased Co was associated with decreased tumor necrosis factor alpha (ρ = -0.56, P = .01) and interleukin 1 beta (ρ = -0.48, P = .03). Increased Cr was associated with decreased tumor necrosis factor alpha (ρ= -0.47, P = .03), interleukin 6 (ρ= -0.43, P = .04), and macrophage inflammatory protein 3 alpha (ρ= -0.47, P = .03).

CONCLUSION

We observed elevated Co, Cr, and Ti concentrations in tissue from necropsy-retrieved TKA. Our findings did not support the hypothesis that tissue metal concentrations were associated with inflammatory cytokines. The results of this research will be useful for the design of future prospective studies.

Self-reported systemic complaints in patients with metal-on-metal hip arthroplasty

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.

Cobalt toxic optic neuropathy and retinopathy: Case report and review of the literature

Purpose

We detail a case of cobalt toxicity with visual and systemic complications, review the pathogenic process for the optic neuropathy and retinopathy, and discuss the controversy of metallic hip prosthesis.

Observations

A 59-year-old female with a history of multiple left hip arthroplasties presented to our clinic with bilateral visual loss. The year prior, she had failure of the hip implant necessitating revision surgery with placement of a chrome-cobalt head. A few months after surgery, she began experiencing blurred and “white, spotty” vision in both eyes in addition to hypothyroidism, cardiomyopathy and neuropathy. The possibility of the patient's symptoms being due to cobalt toxicity from her hip prosthesis was proposed and she was found to have a serum cobalt level >1000 μg/L (normal 0–0.9 ng/mL). Visual acuity was 20/600 in the right and 20/800 in the left eye. There was bilateral temporal optic disc pallor. Goldmann visual field testing demonstrated bilateral central scotomas, optical coherence tomography (OCT) showed severe ganglion cell layer-inner plexiform layer (GCLIPL) thinning and multifocal electroretinography (mfERG) demonstrated decreased amplitudes in both eyes. She underwent a total hip revision arthroplasty with extensive debridement of “black sludge” found within a pseudocapsule. Four days after surgery, cobalt serum levels had significantly decreased to 378 ng/mL. One month after surgery, she had significant improvement in visual acuity (20/150 right eye, 20/250 left eye), Goldmann visual field testing, and mfERG. OCT showed retinal nerve fiber thinning and persistent GCLIPL thinning in both eyes.

Conclusions and Importance

Excessive cobalt levels can result in systemic toxicity leading to visual changes, peripheral neuropathy, hearing loss, cognitive deficits, cardiomyopathy and hypothyroidism. In recent years it has become apparent that cobalt toxicity can be associated with metal-on-metal total hip arthroplasty, or the grinding effects of retained ceramic particles from a fractured ceramic head on a cobalt-chromium femoral head prosthesis.

Blood Management in Revision Total Hip Arthroplasty for Metal-on-Metal Devices: The Efficiency of an Intraoperative Cell Salvage System

BACKGROUND

The aim of this series was to investigate the efficiency of an intraoperative cell salvage system (ICS) removing metal ions during revision of metal-on-metal (MoM) devices to proof the possibility of re-transfusion of the collected blood.

MATERIALS AND METHODS

Between 2014 and 2018, five consecutive patients underwent revision surgery of their MoM total hip arthroplasty due to wear of the polyethylene-metal sandwich inlay or local massive metallosis with aseptic loosing of the cup. Aspiration of joint fluid of all hip prostheses was done and blood was taken to measure the metal ion concentrations, preoperatively. Perioperatively, blood was collected using an ICS before and after filtration and analyzed for Co and Cr concentrations. At that time, there was no re-transfusion of the collected and filtrated blood due to unknown metal ion concentrations.

RESULTS

The mean preoperative serum Co and Cr concentrations in the blood were 31.28 μg/L (range 0.22-77.47) and 17.33 μg/L (range 0.59-51.31), whereas the mean local concentrations in the aspiration fluid were 728-fold and 822-fold higher. The Co and Cr concentrations measured in the collected blood before filtration were 70.61 μg/L (range 9.40-173.00) and 337.21 μg/L (range 8.76-1383.0) and decreased markedly to average concentrations of 15.49 μg/L and 41.88 μg/L, respectively. These differences were statistically not significant (Co: p = 0.117, Cr: p = 0.175), although the mean reduction rates were 78% and 88% for Co and Cr, respectively.

CONCLUSION

The current series showed that in case of revision of MoM hip devices, metal ions are still contained in the collected blood following filtration using a modern high-level ICS. Therefore, we would only recommend blood re-transfusion in case of low preoperative Co and Cr concentrations and sufficient renal function to warrant patients' safety.

Metal Ion Release after Hip and Knee Arthroplasty - Causes, Biological Effects and Diagnostics

All metal implants in human bodies corrode which results in metal ions release. This is not necessarily a problem and represents for most patients no hazard. However, if a critical metal ion concentration is exceeded, local or rarely systemic problems can occur. This article summarizes the mechanisms of metal ion release and its clinical consequences. Several situations can result in increased metal ion release: metal-on-metal hip arthroplasties with increased wear, increased micromotion at taper interfaces, direct metal-metal contact (polyethylene wear, impingement), erroneously used metal heads after ceramic head fracture. Possible problems are in most cases located close to the concerned joint. Furthermore, there are reports about toxic damage to several organs. Most of these reports refer to erroneously used metal heads in revisions after a broken ceramic head. There is currently no evidence of carcinogenic or teratogenic effects of implants but data is not sufficient to exclude possible effects. Cobalt and chromium blood levels (favorably in whole blood) should be measured in patients with suspected elevated metal ions. According to current knowledge levels below 2 µg/l seem to be uncritical, levels between 2 and 7 µg/l are considered borderline with unknown biological consequences and levels above 7 µg/l indicate a local problem which should be further diagnosed. Metal ion levels always need to be interpreted together with clinical symptoms and imaging results.

Total hip replacement failure due to adverse local tissue reaction from both ceramic abrasive wear and trunnion corrosion

The most common sources for metal ions after total hip arthroplasty (THA) are the bearing surface in metal-on-metal articulations and trunnion corrosion. Concomitant dual interface failure is an uncommon complication in metal-on-polyethylene THA. We report an unusual case of a 59-year-old woman with ceramic-on-ceramic THA in 2005, who underwent revision to metal-on-polyethylene THA 4 years later after femoral head fracture. Subsequently, she developed substantial adverse local tissue reaction and significant metal ion elevation and the failure was found to be due to both wear at the bearing surface and corrosion at the head neck junction requiring second revision. Findings included massive adverse local tissue reaction, abductor mechanism destruction, osteolysis, and corrosion damage of the trunnion. Abrasive damage of the trunnion was also noted, but prior abrasion from the original ceramic fracture could not be ruled out. Postoperative course at 14 months demonstrates 95% and 64% reduction in cobalt and chromium levels respectively, with symptom resolution.

[Total hip arthroplasty in young patients : Bearings and custom-made prostheses]

BACKGROUND

Carefully and correctly implanted components are the prerequisite for the lifespan of a prosthesis. Whether higher levels of activity lead to prior failure of total hip arthroplasty in young patients is controversially discussed. The right choice of bearings is still of great relevance.

BEARINGS

Ceramic-on-ceramic as well as polyethylene-on-ceramic bearings achieve comparable results, although ceramic-on-ceramic bearings should be avoided in patients with high demands on their range of motion. Polyethylene-on-metal bearings also show good clinical results, if corrosion between head and stem is absent. Metal-on-metal bearings lead to adverse systemic effects due to metal wear and should be implanted in individual cases only, e. g. as hip resurfacing. Alternative bearings have to give proof of effectivity first. Custom-made prostheses constitute an option for young patients with special conditions of hip anatomy. Planning and study results of these prostheses are elucidated in this review article.

High risk of complications using metal heads after ceramic fracture in total hip arthroplasty

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.

Heart transplant secondary to cobalt toxicity after hip arthroplasty revision

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.

Cobalt cardiomyopathy in hip arthroplasty

Background

Cobalt toxicity-related cardiomyopathy in hip arthroplasty has recently been reported in the literature. The purpose of this review is to identify and assess available published evidence of cardiomyopathy in hip arthroplasty patients and to derive recommendations for management.

Methods

We evaluated 23 cases reported until October 2018 and stratified them into 3 categories, based upon pre-existing risk factors for cardiomyopathy, histological confirmation, and evidence of systemic signs of cobalt toxicity.

Results

Cobalt toxicity was considered to be the definite cause of cardiomyopathy in 8 cases, and probably contributory in 13 cases. Two cases were considered to have developed cardiomyopathy secondary to pre-existing risk factors. Majority of the patients had a good recovery of cardiac function after hip revision and cardiac management, but 5 cases deteriorated and died.

Conclusions

Although cobalt-related cardiomyopathy has been reported in a small number of cases of hip arthroplasty, a delay or missed diagnosis may lead to significant morbidity and mortality. Timely diagnosis, removal of causative implant, and avoidance of metal articulations in revision for fractured ceramic implants may help in an effective management.

Severe Cardiomyopathy Due to Arthroprosthetic Cobaltism: Report of Two Cases with Different Outcomes

Cobalt-induced cardiomyopathy is a well-known but uncommon disease, and the physician must maintain a high index of suspicion in order to make a timely diagnosis. We report two patients with cobalt-induced cardiomyopathy. Both patients developed progressively worsening symptoms of cobalt toxicity following revision of a fractured ceramic-on-ceramic total hip replacement to a metal-on-polyethylene bearing. In both patients, echocardiography showed LV hypertrophy, biventricular systolic dysfunction, and a large amount of pericardial effusion. Due to decompensated heart failure, both patients were initially considered candidates for heart transplantation. One patient was diagnosed with cobalt-induced cardiomyopathy before transplantation. He received cobalt chelation therapy and revision surgery, which led to complete recovery of heart function. In the other patient, the diagnosis was not made until the time of heart transplantation. The gross examination of the explanted heart revealed typical features of cobalt cardiotoxicity, which was then diagnosed as cobalt-induced cardiomyopathy. These cases emphasise the importance of early diagnosis and prompt treatment of cobalt intoxication.

Systemic cobaltism manifesting as oral mucosal discoloration and metallic gustation after metal-on-metal hip resurfacing

Systemic cobaltism is a debilitating complication of metal-on-metal (MoM) arthroplasty. In this report, we review a case of a 54-year-old female with metallosis from a MoM hip resurfacing and varying degrees of black discoloration of her tongue and metallic gustation as a result of systemic cobaltism. After explanting the metal components, thorough debridement, and conversion to ceramic-on-polyethylene arthroplasty, the patient's oral mucosal discoloration and metallic gustation resolved. This represents the first documentation of systemic cobaltism from MoM hip resurfacing manifesting as oral mucosal discoloration and metallic gustation with resolution after explant, debridement, and conversion to ceramic-on-polyethylene total hip arthroplasty.

Total hip arthroplasty and cardiovascular complications: a review

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.

Catastrophic ceramic liner failure-The subtle signs of a non-engaged ceramic liner

Ceramic earrings have an established and successful history in total hip replacement. Occasionally, these articulations have problems, which include squeaking and implant fracture.

Characteristics of Cobalt-Related Cardiomyopathy in Metal Hip Implant Patients: An Evaluation of 15 Published Reports

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.

Myocardial Cobalt Levels Are Elevated in the Setting of Total Hip Arthroplasty

BACKGROUND

Arthroplasty implants commonly contain elemental metal that may undergo wear-related release. Recently, cases of hip implant-associated myocardial injury have been reported. However, we are not aware of any previous study that has systematically measured myocardial metal levels or examined the relationship with total hip arthroplasty (THA).

METHODS

Archives of our institution were queried for autopsies of individuals who had undergone THA between 1990 and 2013. Myocardial tissue samples were analyzed for cobalt (Co) and chromium (Cr) levels with inductively coupled plasma mass spectroscopy. Seventy-five Co/Cr-on-polyethylene THA cases were included (mean age at time of death = 77.4 years; 49% women) as were 73 non-arthroplasty controls matched for age, sex, and history of hypertension and diabetes mellitus.

RESULTS

Significantly higher median myocardial concentrations of Co were observed in individuals with THA compared with controls (0.12 versus 0.06 μg/g, p < 0.0001). The median Co concentration was 69% higher in patients who had undergone THA revision (0.169 μg/g) than in those who underwent primary THA (0.100 μg/g; p = 0.004). In general, higher Co levels were observed in those with multiple replaced joints, although this finding only trended toward significance. Cardiomegaly, interstitial fibrosis, and decreased ejection fraction were observed more frequently in the postmortem samples of patients with implants than in those of controls (p = 0.0002, 0.044, and 0.0039, respectively).

CONCLUSIONS

We believe this to be the first study to quantify metal levels in cardiac tissue in patients with and without joint replacement. The elevated Co levels, in concert with cardiomegaly and increased interstitial fibrosis found during autopsy, in the arthroplasty cohort are novel, important findings. Although Co levels were significantly elevated above those in controls, the majority were below those seen in clinical case reports of death from Co cardiotoxicity associated with metal-on-metal prostheses.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Assessing for Cardiotoxicity from Metal-on-Metal Hip Implants with Advanced Multimodality Imaging Techniques

BACKGROUND

High failure rates of metal-on-metal (MoM) hip implants prompted regulatory authorities to issue worldwide safety alerts. Circulating cobalt from these implants causes rare but fatal autopsy-diagnosed cardiotoxicity. There is concern that milder cardiotoxicity may be common and underrecognized. Although blood metal ion levels are easily measured and can be used to track local toxicity, there are no noninvasive tests for organ deposition. We sought to detect correlation between blood metal ions and a comprehensive panel of established markers of early cardiotoxicity.

METHODS

Ninety patients were recruited into this prospective single-center blinded study. Patients were divided into 3 age and sex-matched groups according to implant type and whole-blood metal ion levels. Group-A patients had a ceramic-on-ceramic [CoC] bearing; Group B, an MoM bearing and low blood metal ion levels; and Group C, an MoM bearing and high blood metal-ion levels. All patients underwent detailed cardiovascular phenotyping using cardiac magnetic resonance imaging (CMR) with T2*, T1, and extracellular volume mapping; echocardiography; and cardiac blood biomarker sampling. T2* is a novel CMR biomarker of tissue metal loading.

RESULTS

Blood cobalt levels differed significantly among groups A, B, and C (mean and standard deviation [SD], 0.17 ± 0.08, 2.47 ± 1.81, and 30.0 ± 29.1 ppb, respectively) and between group A and groups B and C combined. No significant between-group differences were found in the left atrial or ventricle size, ejection fraction (on CMR or echocardiography), T1 or T2* values, extracellular volume, B-type natriuretic peptide level, or troponin level, and all values were within normal ranges. There was no relationship between cobalt levels and ejection fraction (R = 0.022, 95% confidence interval [CI] = -0.185 to 0.229) or T2* values (R = 0.108, 95% CI = -0.105 to 0.312).

CONCLUSIONS

Using the best available technologies, we did not find that high (but not extreme) blood cobalt and chromium levels had any significant cardiotoxic effect on patients with an MoM hip implant. There were negligible-to-weak correlations between elevated blood metal ion levels and ejection fraction even at the extremes of the 95% CI, which excludes any clinically important association.

LEVEL OF EVIDENCE

Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Mild or moderate renal insufficiency does not increase circulating levels of cobalt and chromium in patients with metal-on-metal hip arthroplasty

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 m2) was seen in 74 patients. Mild renal insufficiency (GFR 60 to 89 ml/min/1.73 m2) was seen in 90 patients and moderate renal insufficiency (GFR 30 to 59 ml/min/1.73 m2) 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 blood metal ion levels or between GFR and blood metal ion levels. Linear regression analysis did not show any association between Co and Cr levels and GFR.

Conclusion

We did not find any association between GFR and blood metal ion levels. Consequently, the accumulation of Co and Cr in blood due to renal insufficiency does not seem to be a major risk in patients with mild or moderate renal insufficiency. Cite this article Bone Joint J 2017;99-B:1147–52

Fatal Cobalt Toxicity after a Non-Metal-on-Metal Total Hip Arthroplasty

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.

Ceramic-on-ceramic bearing fractures in total hip arthroplasty

Aims

Ceramic-on-ceramic (CoC) bearings in total hip arthroplasty (THA) are commonly used, but concerns exist regarding ceramic fracture. This study aims to report the risk of revision for fracture of modern CoC bearings and identify factors that might influence this risk, using data from the National Joint Registry (NJR) for England, Wales, Northern Ireland and the Isle of Man.

Patients and Methods

We analysed data on 223 362 bearings from 111 681 primary CoC THAs and 182 linked revisions for bearing fracture recorded in the NJR. We used implant codes to identify ceramic bearing composition and generated Kaplan-Meier estimates for implant survivorship. Logistic regression analyses were performed for implant size and patient specific variables to determine any associated risks for revision.

Results

A total of 222 852 bearings (99.8%) were CeramTec Biolox products. Revisions for fracture were linked to seven of 79 442 (0.009%) Biolox Delta heads, 38 of 31 982 (0.119%) Biolox Forte heads, 101 of 80 170 (0.126%) Biolox Delta liners and 35 of 31 258 (0.112%) Biolox Forte liners. Regression analysis of implant size revealed smaller heads had significantly higher odds of fracture (chi-squared 68.0, p < 0.001). The highest fracture risk was observed in the 28 mm Biolox Forte subgroup (0.382%). There were no fractures in the 40 mm head group for either ceramic type. Liner thickness was not predictive of fracture (p = 0.67). Body mass index (BMI) was independently associated with revision for both head fractures (odds ratio (OR) 1.09 per unit increase, p = 0.031) and liner fractures (OR 1.06 per unit increase, p = 0.006).

Conclusions

We report the largest independent study of CoC bearing fractures to date. The risk of revision for CoC bearing fracture is very low but previous studies have underestimated this risk. There is good evidence that the latest generation of ceramic has greatly reduced the odds of head fracture but not of liner fracture. Small head size and high patient BMI are associated with an increased risk of ceramic bearing fracture. Cite this article: Bone Joint J 2017;99-B:1012–19.

Revision Total Hip Arthroplasty for Fractured Ceramic Bearings: A Review of Best Practices for Revision Cases

BACKGROUND

Total hip arthroplasty revision for a fractured ceramic bearing is rare but offers unique challenges. The purpose of this review was to provide a summary of existing literature on fractured ceramic bearings.

METHODS

Two authors performed a literature search of the MEDLINE OVID and PubMed databases with the following search terms: ceramic, fracture, total hip arthroplasty, and revision.

RESULTS

The search identified 228 articles of which 199 were selected for review.

CONCLUSIONS

It is mandatory to perform a complete synovectomy and thorough debridement of the fractured ceramic fragments. A well-fixed acetabular component should be removed if either the locking mechanism is damaged or the component is malpositioned. If the femoral stem taper is damaged, the femoral stem should be removed. However, if minimal damage is present, the femoral stem may be retained and revised using a fourth generation ceramic head with a titanium sleeve. Metal bearings should be avoided and revision with ceramic bearings should be performed whenever possible.

Cobalt toxicity in humans-A review of the potential sources and systemic health effects

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 B₁₂, 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 300μg/l (100μg/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 Co²⁺. As the latter is believed to be the primary toxic form, monitoring of the free fraction of Co²⁺ 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.

Adverse local tissue reaction after 2 revision hip replacements for ceramic liner fracture: A case report

INTRODUCTION

In younger patients, ceramic-on-ceramic (CoC) bearing surfaces are usually recommended for total hip replacement (THR) because of their low wear rate and longer expected functional life. Although technical advancements have reduced the risk of ceramic bearings fracture, this complication remains a major concern.

CASE DESCRIPTION

We present the case of a 56-year-old patient undergoing 3 revision hip arthroplasties of the right hip due to ceramic liner fractures. Initial THR (2008) was performed with a CoC bearing, followed by liner fracture due to trauma a year later. The acetabular component and liner were replaced, with a minor incongruence between the old head and new insert. The 2nd ceramic insert fractured 3.5 years later, following minor trauma. Upon revision, the bearing surface was changed to metal-on-polyethylene (MoP). The performed retrieval analysis demonstrated stripe and rim wear, and evidence of adhesive wear. The patient was referred to us a month later, with a fistula on the lateral side of the hip, discharging black, petroleum-like liquid. Radiology showed well-fixed implants, no dislocation and no apparent polyethylene wear. Microbiological assessment of the discharge showed no infection. Intraoperatively massive metallosis was noticed, with stable acetabular and femoral components. The metal femoral head was heavily abraded, with almost 1% volumetric wear. Hematoxylin and eosin stained frozen tissue samples showed muscular and adipose tissue necrosis, while polarized light microscopy highlighted metal, polyethylene, and ceramic particles.

CONCLUSION

The present case is yet another report showing the adverse outcomes of using MoP bearings for revision after ceramic liner fracture in THR.