Patch Testing With Nickel, Cobalt, and Chromium in Patients With Suspected Allergic Contact Dermatitis.

Background: Allergic contact dermatitis is frequently caused by metals, including multiple metals simultaneously. Objectives: To assess characteristics and associations of positive and clinically relevant patch test (PT) reactions with solitary and concurrent metal sensitization. Methods: A retrospective analysis of PT results for nickel, cobalt, and/or chromium from the North American Contact Dermatitis Group between 2001 and 2018 (n = 43,522). Results: 18.0% had a positive/allergic reaction to nickel sulfate hexahydrate, 7.3% to cobalt chloride hexahydrate, and 3.0% to potassium dichromate. 87.9% patients had a currently relevant reaction to 0, 9.4% to 1, and 2.7% to multiple metals tested. Patients with 1 versus no currently relevant reactions to metal were more likely to have a primary dermatitis site of trunk, feet, and ears; patients with currently relevant reactions to multiple metals had more dermatitis affecting the trunk and ears. Metal sources varied by co-reacting metal, especially for patients with cobalt and chromium allergy. Jewelry was the most commonly identified source of nickel and cobalt for both solitary and concurrent metal allergy. Conclusions: Sensitization to multiple metals occurred in 6% of patients. Allergen sources varied between patients with sensitivity to 1 metal versus those who had concurrent sensitivity to cobalt and/or chromium.

Hypersensitivity to metals in metal-on-metal hip arthroplasty: a prospective study of one hundred and thirty five lymphocyte transformation tests.

BACKGROUND: Metal allergy remains a controversial topic in the orthopaedic community. It is not known if or to what degree metal sensitivity contributes to inflammatory soft tissue failures, unexplained residual pain, or clinical complications after total joint replacement with metal prostheses. METHODS: We investigated the efficacy of the lymphocyte transformation test (LTT) in predicting adverse outcomes in patients after receiving a metal joint replacement. Our study cohort consists of 135 metal-on-metal hip resurfacing arthroplasty cases performed between 2013 and 2015. All study patients had an LTT preoperatively. We retrospectively analyzed clinical outcomes and failures for our cohort. RESULTS: There was no difference in LTT reactivity between men and women. Of the 135 patients tested, 46 (34.1% of cohort) tested positive to at least one of the materials comprising their implant, and 78 patients (57.8%) had at least one reactive score to any component of the LTT. After a minimum follow-up of two years, we did not observe an allergic response to the implant in any patients. There were no failures requiring revision. We observed a 2.2% rate of moderate residual pain; no patients with residual pain tested positive for metal sensitivity. When patients with moderate-high LTT reactivity (30.4% of cohort) were compared to the remainder of the study group, there was no difference in HHS or UCLA activity score. There was no correlation between blood metal ion levels and LTT reactivity. CONCLUSION: We were unable to prove any predictive value of the LTT. We failed to identify hypersensitivity to metals in patients with metal-on-metal hip resurfacing arthroplasty.

Quantification and severity grading of femoral vessel compression by adverse reactions to metal debris in metal-on-metal total hip arthroplasty.

INTRODUCTION: Metal-on-metal (MoM) total hip arthroplasty (THA) may cause adverse reactions to metal debris (ARMD). ARMD causing femoral vessel compression with serious complications has been described in case reports, but the rate of compression by ARMD is not known. This study aims to investigate the rate, and quantify the severity, of femoral vessel compression in MoM hips with ARMD lesions. METHODS: Patients under surveillance for MoM THA investigated with MRI were studied. In patients with confirmed ARMD, femoral artery (FA) and vein (FV) diameters were measured at the point of maximal compression and compared to contralateral vessels. The primary outcome measure was presence or absence of compression. Cases were then classified by compression ratios. Secondary outcome measures were rates of deep vein thrombosis, revision surgery and time to ARMD from index procedure. RESULTS: MRI scans for 436 patients with MoM THA were screened. Of these, 211/436 (48.4%) showed evidence of ARMD. Measurements were obtained on 133/211 (63.0%) patients. The FV was compressed in 102/133 (76.7%) and FA in 58/133 (43.6%), while 31/133 (23.3%) patients had no compression. In FVs, 42 demonstrated mild compression, 39 moderate and 21 severe. In FAs, none were severely compressed, 6 were moderate and 52 showed mild compression. There were 3 DVT cases, 2 in patients with moderate FV compression and 1 in patients without FV compression. Revision rates were highest in patients with severe FV compression (14/21, 66.7%). The mean time for MRI-diagnosed ARMD from index procedure was 8 years and 1 month (range 11 months-14.5 years). CONCLUSIONS: Extra-luminal compression of the femoral vessels was found in >75% of patients with ARMD. Although it is not clear whether revision for femoral vessel compression is required, quantification of FV compression may be useful for surgeons and radiologists considering revision for ARMD.

The use of dual mobility cups in revision total hip arthroplasty for failed large head metal-on-metal bearings.

PURPOSE: Revision of failed large head metal-on-metal (MoM) total hip arthroplasty (THA) is a challenging procedure particularly to reconstruct acetabular bone defect due to osteolysis and to achieve hip stability due to soft tissue damages, both potentially caused by adverse reaction to metal debris (ARMD). This study aimed to evaluate the outcome of dual mobility cup (DMC) constructs in revision THA for failed large head MoM bearings with a special attention to the occurrence of dislocation or re-revision. METHODS: Between 2015 and 2019, 57 patients (64 THAs, 41 men, mean age = 65 ± 10 years) underwent revision for MoM THA with the use of DMC were prospectively included in our total joint registry. Mean time to revision was 11 ± 2.5 years. The causes for revision were adverse reaction to metal debris (ARMD) in 49 THAs (76%), painful hip with elevated blood cobalt-chromium ions in seven (11%), and acetabular aseptic loosening in eight (13%). The revision was complete in 22 THAs (34%) and acetabular only in 42 (66%). Clinical and radiographic outcomes, complications, and re-revisions were evaluated at most recent follow-up. RESULTS: At mean follow-up of six ± 1.5 years, the pre- to postoperative Harris Hip Score improved from 74 ± 19 to 92 ± 4 (p = 0.004). Complications occurred in 11 cases (17%): five dislocations (8%), three periprosthetic infections (5%), two aseptic loosening of the acetabular component (3%), and two periprosthetic fractures (3%). Re-revision was required in six cases (9%). CONCLUSION: The use of DMC is a reliable option to prevent instability and ensure a stable acetabular reconstruction in revision THA for failed large head MoM bearings. However, dislocation after revision remains a concern, particularly in cases of severe soft tissue damage related to ARMD.

Enteral N-acetylcysteine to reduce serum cobalt concentrations secondary to prosthetic knee-associated metallosis: A case report.

PURPOSE: Cobalt metallosis is a rare but dangerous complication of total joint arthroplasty resulting from deterioration of the joint leading to metal-on-metal friction and breakdown. Potential manifestations vary in severity and include dilated cardiomyopathy, thyroid dysfunction, cognitive disturbances, neuropathy, fatigue, and weakness. The therapeutic role of N-acetylcysteine in metallosis has been investigated due to its ability to chelate with heavy metal ions, such as cobalt and chromium. SUMMARY: Here we report the case of a 71-year-old female who presented with suspected metallosis diagnosed in the outpatient setting due to symptoms of significant weight loss and failure to thrive. This metallosis was secondary to the hardware breakdown of a left knee revision roughly 6 years previously. The patient was not a surgical candidate due to her poor nutrition status and was started on nasojejunal tube feeds along with N-acetylcysteine 600 mg by mouth twice daily for 45 days. The patient's serum cobalt levels decreased from 61.7 µg/L on admission to 16.2 µg/L prior to her undergoing proper revision of the left knee roughly 2 months after admission to the hospital. The patient tolerated treatment well and was able to be discharged the day after surgery, with no further complaints or complications. CONCLUSION: This case report contributes to the body of literature suggesting that administration of N-acetylcysteine can reduce serum cobalt concentrations, without notable adverse effects, in the context of prosthetic knee-associated metallosis.

Metal-induced autoimmunity in neurological disorders: A review of current understanding and future directions.

Autoimmunity is a multifaceted disorder influenced by both genetic and environmental factors, and metal exposure has been implicated as a potential catalyst, especially in autoimmune diseases affecting the central nervous system. Notably, metals like mercury, lead, and aluminum exhibit well-established neurotoxic effects, yet the precise mechanisms by which they elicit autoimmune responses in susceptible individuals remain unclear. Recent studies propose that metal-induced autoimmunity may arise from direct toxic effects on immune cells and tissues, coupled with indirect impacts on the gut microbiome and the blood-brain barrier. These effects can activate self-reactive T cells, prompting the production of autoantibodies, inflammatory responses, and tissue damage. Diagnosing metal-induced autoimmunity proves challenging due to nonspecific symptoms and a lack of reliable biomarkers. Treatment typically involves chelation therapy to eliminate excess metals and immunomodulatory agents to suppress autoimmune responses. Prevention strategies include lifestyle adjustments to reduce metal exposure and avoiding occupational and environmental risks. Prognosis is generally favorable with proper treatment; however, untreated cases may lead to autoimmune disorder progression and irreversible organ damage, particularly in the brain. Future research aims to identify genetic and environmental risk factors, enhance diagnostic precision, and explore novel treatment approaches for improved prevention and management of this intricate and debilitating disease.

Lumen-apposing metal stents versus traditional self-expanding metal stents for endoscopic ultrasound-guided drainage of pancreatic fluid collections: a systematic review and meta-analysis.

BACKGROUND: Endoscopic drainage has become the preferred treatment for pancreatic fluid collections (PFCs). There is still a lack of reliable evidence to prove which metal stent is the best choice for endoscopic ultrasound (EUS)-guided drainage of PFCs. In this study, we aimed to evaluate the efficacy and safety of lumen-apposing metal stents (LAMS) compared to traditional self-expanding metal stents (SEMS) in meta-analysis. METHODS: We systematically searched PubMed, Embase, Web of Science, and Cochrane Library up to July 15, 2023. Relevant publications that compared LAMS with traditional SEMS for drainage of patients' PFCs under EUS-guidance were included. This meta-analysis assessed endpoints using Review Manager 5.3 and Stata 14.0 statistical software. RESULT: Nine citations comprising 707 patients with PFCs were included. The clinical success rate of LAMS tended to be higher than that of SEMS (RR = 1.07, 95%CI [1.00, 1.15], P = 0.05). LAMS had a lower technical success rate (RR = 0.97, 95%CI [0.94, 0.99], P = 0.02) and faster procedure time (minutes) (MD = - 24.29, 95%CI [- 25.59, - 22.99], P < 0.00001) compared to SEMS. In addition, LAMS had fewer overall adverse events (RR = 0.64, 95%CI [0.48, 0.87], P = 0.004). For specific adverse events, LAMS had fewer migration (RR = 0.37, 95%CI [0.19, 0.72], P = 0.003), occlusion (RR = 0.43, 95%CI [0.22, 0.82], P = 0.01) and infection (RR = 0.38, 95%CI [0.20, 0.70], P = 0.002). There was no significant difference in bleeding and perforation between the two stents. For hospital stay (days), LAMS group was similar to SEMS group (MD = - 3.34, 95%CI [- 7.71, - 1.03], P = 0.13). Regarding recurrence, LAMS group was fewer than SEMS group (RR = 0.41, 95%CI [0.21, 0.78], P = 0.007). CONCLUSION: Compared to traditional SEMS, LAMS has a higher clinical success rate, faster procedure time, fewer adverse events, similar hospital stay and lower recurrence rate in EUS-guided drainage of PFCs. LAMS is a good choice with a high technical success rate over 95%, and using a shorter length or "one-step" operation can further improve it. Richer placement experience is required for LAMS placement under EUS-guidance.

A Sarcoma Masquerading as a Pseudotumor After Total Hip Arthroplasty: A Case Report.

CASE: There is an increasing emphasis on adverse reactions to metal debris around prosthetic hip implants. We present a case report of a patient with increasing pain around a previous total hip arthroplasty and magnetic resonance imaging findings consistent with a pseudotumor. Serum metal ion levels were not elevated and initial biopsy findings inconclusive. The patient was diagnosed with an extraskeletal chondrosarcoma after revision total hip arthroplasty and subsequently underwent external hemipelvectomy with negative margins. CONCLUSION: This report highlights the importance of remaining vigilant for malignant sarcomas presenting as pseudotumors around hip replacements, particularly in the absence of abnormal metal ion levels or definitive biopsy results.

Long-term environmental metal exposure is associated with hypomethylation of CpG sites in NFKB1 and other genes related to oncogenesis.

BACKGROUND: Long-term environmental exposure to metals leads to epigenetic changes and may increase risks to human health. The relationship between the type and level of metal exposure and epigenetic changes in subjects exposed to high concentrations of metals in the environment is not yet clear. The aim of our study is to find the possible association of environmental long-term exposure to metals with DNA methylation changes of genes related to immune response and carcinogenesis. We investigated the association of plasma levels of 21 essential and non-essential metals detected by ICP-MS and the methylation level of 654 CpG sites located on NFKB1, CDKN2A, ESR1, APOA5, IGF2 and H19 genes assessed by targeted bisulfite sequencing in a cohort of 40 subjects living near metal mining area and 40 unexposed subjects. Linear regression was conducted to find differentially methylated positions with adjustment for gender, age, BMI class, smoking and metal concentration. RESULTS: In the metal-exposed group, five CpGs in the NFKB1 promoter region were hypomethylated compared to unexposed group. Four differentially methylated positions (DMPs) were associated with multiple metals, two of them are located on NFKB1 gene, and one each on CDKN2A gene and ESR1 gene. Two DMPs located on NFKB1 (chr4:102500951, associated with Be) and IGF2 (chr11:2134198, associated with U) are associated with specific metal levels. The methylation status of the seven CpGs located on NFKB1 (3), ESR1 (2) and CDKN2A (2) positively correlated with plasma levels of seven metals (As, Sb, Zn, Ni, U, I and Mn). CONCLUSIONS: Our study revealed methylation changes in NFKB1, CDKN2A, IGF2 and ESR1 genes in individuals with long-term human exposure to metals. Further studies are needed to clarify the effect of environmental metal exposure on epigenetic mechanisms and pathways involved.

Failure of a Femoral Revision Knee Component with Chemical Corrosion and Elevated Metal Ions: A Case Report and Literature Review.

CASE: Failure of the modular junction in revision total knee arthroplasty is a rare complication. We report a patient with late, atraumatic failure of a modern, modular revision femoral component, with preoperative elevation of serum cobalt and chromium levels. Retrieval analysis showed extensive chemical corrosion. CONCLUSION: Failure of a modern, modular femoral component may cause metal synovitis and elevated serum metal levels. Subtle radiographic changes and preoperative serum metal levels may identify this complication.

Metal Exposure and Risk of Parkinson Disease: A Systematic Review and Meta-Analysis.

Metal exposure has been suggested as a possible environmental risk factor for Parkinson disease (PD). We searched the PubMed, EMBASE, and Cochrane databases to systematically review the literature on the relationship between metal exposure and PD risk and to examine the overall quality of each study and the exposure assessment method. A total of 83 case-control studies and 5 cohort studies published during the period 1963-July 2021 were included, of which 73 were graded as being of low or moderate overall quality. Investigators in 69 studies adopted self-reported exposure and biomonitoring after disease diagnosis for exposure assessment approaches. The meta-analyses showed that concentrations of copper and iron in serum and concentrations of zinc in either serum or plasma were lower, while concentrations of magnesium in CSF and zinc in hair were higher, among PD cases as compared with controls. Cumulative lead levels in bone were found to be associated with increased risk of PD. We did not find associations between other metals and PD. The current level of evidence for associations between metals and PD risk is limited, as biases from methodological limitations cannot be ruled out. High-quality studies assessing metal levels before disease onset are needed to improve our understanding of the role of metals in the etiology of PD.

Association of metal exposure with arterial stiffness in Chinese adults.

BACKGROUND: Arterial stiffness is an important indicator of cardiovascular aging. However, studies assessing the association between metal exposure and arterial stiffness are limited. OBJECTIVE: The aim of this study was to investigate the independent and joint associations of metal exposure with arterial stiffness. METHODS: This cross-sectional study recruited 2982 Chinese adults from August 2018 to March 2019 in Wuhan, China. The concentrations of 20 urinary metals were determined using inductively coupled plasma mass spectrometer. Arterial stiffness was assessed by brachial-ankle pulse wave velocity (baPWV). We used generalized linear model (GLM) to estimate the association of single metal exposure with baPWV. We used weighted quantile sum (WQS) regression to estimate the association of metal mixture with baPWV. RESULTS: In GLM regression analysis, each doubling of urinary copper (Cu) and chromium (Cr) concentrations were associated with 6.48 (95 % CI: 2.51-10.45) cm/s and 3.78 (95 % CI: 0.42-7.14) cm/s increase in baPWV, respectively. In WQS regression analysis, each unit increase in WQS index of the metal mixture was associated with a 9.10 (95 % CI: 2.39-15.82) cm/s increase in baPWV. Cu, Zn, and Cr were the dominant urinary metals associated with baPWV. CONCLUSION: Metal exposure, both individually and in mixture, was associated with an increased risk of arterial stiffness. Our findings may provide a target for preventative strategies against cardiovascular aging.

Sex-specific associations of single metal and metal mixture with handgrip strength: a cross-sectional study among Chinese adults.

Metallic elements are ubiquitous in the natural environment and always collaborate to affect human health. The relationship of handgrip strength, a marker of functional ability or disability, with metal co-exposure remains vague. In this study, we aimed to investigate the effect of metal co-exposure on sex-specific handgrip strength. A total of 3594 participants (2296 men and 1298 women) aged 21 to 79 years recruited from Tongji Hospital were included in the present study. Urinary concentrations of 21 metals were measured by inductively coupled plasma mass spectrometer (ICP-MS). We used linear regression, restricted cubic spline (RCS) model, and weighted quantile sum (WQS) regression to evaluate the association of single metal as well as metal mixture with handgrip strength. After adjusting for important confounding factors, the results of linear regression showed that vanadium (V), zinc (Zn), arsenic (As), rubidium (Rb), cadmium (Cd), thallium (Tl), and uranium (U) were adversely associated with handgrip strength in men. The results of RCS showed a non-linear association between selenium (Se), silver (Ag), and nickel (Ni) with handgrip strength in women. The results of WQS regression revealed that metal co-exposure was inversely related to handgrip strength for men (ß = -0.65, 95% CI: -0.98, -0.32). Cd was the critical metal in men (weighted 0.33). In conclusion, co-exposure to a higher level of metals is associated with lower handgrip strength, especially among men, and Cd may contribute most to the conjunct risk.

Is it safe for patients with metal implants to have iontophoresis treatment?

BACKGROUND: Iontophoresis passes electrical charge through skin to deliver drugs or reduce excessive sweating. Treatments can be performed by patients at home following initial instruction. A limitation of the technique is that patients are not permitted to have metal implants. These are hypothesized to increase the risk of electric shock, cause localized heating and/or corrosion. OBJECTIVES: To investigate whether metallic materials (titanium, stainless steel and copper) placed in the iontophoresis circuit would lead to an unfavourable outcome regarding corrosion or local heating of the metallic object. METHODS: This was carried out using mass loss and temperature change experiments, together with atomic force microscopy for stainless steel, to assess any surface roughness changes. The investigations were carried out under accelerated conditions (70 V compared with standard use 20-30 V). RESULTS: No changes in mass or clinically significant changes in temperature of any of the metallic objects (or surface roughness for stainless steel) were observed. CONCLUSIONS: This study suggests that patients with these metallic implants can safely undergo iontophoresis treatment. Further work is needed to review the impact on metallic implants with repeated exposure to the iontophoresis system to represent real-world evidence.

Characterization of ion release from a novel biomaterial, Molybdenum-47.5Rhenium, in physiologic environments.

BACKGROUND CONTEXT: Metals from spinal implants are released into surrounding tissues by various mechanisms. Metal ion release has been associated with clinical implant failure, osteolysis, and remote site accumulation with adverse events. Significant corrosion and associated metal ion release has been described with currently used spinal implant alloys. A novel metal alloy, Molybdenum-47.5Rhenium alloy (MoRe®), was approved for use in medical implants in 2019 by the FDA. PURPOSE: To evaluate the metal ion release profile of MoRe alloy after immersion in both a stable physiologic, as well as in an inflammatory environment. STUDY DESIGN: In vitro study. METHODS: The ion release profile of the MoRe alloy was comprehensively evaluated in-vitro after prolonged immersion in physiologic and inflammatory environments. Ion concentration analyses were then conducted using inductively coupled plasma-mass spectrometry (ICP-MS) methods. Comparative testing of titanium (Ti-6Al-4V) and cobalt chromium (Co-28Cr-6Mo) was also performed. RESULTS: Under baseline physiologic conditions, the MoRe alloy demonstrates very low molybdenum and rhenium ion release rates throughout the 30-day test period. During the first time interval (day 0-1), low levels of molybdenum and rhenium ions are detected (<0.3 µg/cm2 day) followed by a rapid reduction in the ion release rates to <0.05 µg/cm2 day during the second time interval (days 1-3) followed by a further reduction to very low steady-state rates <0.01 µg/cm2 day during the third time interval (days 3-7), which were maintained through 30 days. In the inflammatory condition (H2O2 solution), there was a transient increase in the release of molybdenum and rhenium ions, followed by a return to baseline ion release rates (days 2-4), with a further reduction to low steady-state rates of ∼0.01 µg/cm2 day (days 4-8). The measured molybdenum and rhenium ion release rates in both steady state (<0.01 µg/cm2 day), and inflammatory environments (0.01 µg/cm2 day) were far below the established FDA-permitted daily exposure (PDE) of 1,900 µg/cm2 day for molybdenum and 4,400 µg/cm2 day for rhenium. In contrast, titanium and cobalt chromium approached or exceeded their established PDE values in an inflammatory environment. CONCLUSIONS: The novel biomaterial MoRe demonstrated a lower metal ion release profile in both a physiologic and inflammatory environment and was well below the established PDE.  Comparative testing of the cobalt-chromium and titanium alloys found higher levels of ion release in the inflammatory environment that exceeded the PDE for cobalt and vanadium.

Electrocautery-enhanced Lumen-apposing Metal Stents in the Management of Symptomatic Pancreatic Fluid Collections: Results From the Multicenter Prospective Pivotal Trial.

BACKGROUND AND AIMS: Endoscopic decompression is considered a first-line treatment for symptomatic pancreatic fluid collections (PFCs). A lumen-apposing metal stent (LAMS) with an electrocautery-enhanced delivery system [electrocautery-enhanced lumen-apposing metal stent (ELAMS)] may facilitate this procedure. This study evaluated the safety and efficacy of ELAMS in the management of symptomatic PFCs. PATIENTS AND METHODS: A multicenter, nonblinded, prospective, Food and Drug Administration (FDA)-approved, investigational device exemption clinical trial was conducted. Enrollment criteria included symptomatic PFCs ≥6 cm with ≥70% fluid fraction. Subjects were followed prospectively for safety, efficacy, and resolution of the collections. Primary endpoint success was defined as ≥50% reduction in PFC size. Clinical outcomes were compared with our previously published series of LAMS without the cautery-enhanced delivery system. RESULTS: The target enrollment of 30 patients was achieved in 7 US tertiary care centers. All patients underwent successful placement of the ELAMS. The mean procedure duration, stent placement time, and fluoroscopy exposures were 28.1±12.5, 5.8±2.6, and 1.8±1.6 minutes, respectively. Eight patients had no fluoroscopy. The primary endpoint was achieved in 83.3% of patients. Two adverse events were attributed to the ELAMS: 1 bleeding upon stent removal and 1 stent migration. Relative to the comparator noncautery LAMS multicenter trial (N=33, 8 tertiary centers), there was a significantly shorter procedure duration [36 min ( P <0.001)] with similar technical and clinical outcomes in the ELAMS cohort. CONCLUSION: LAMS placed using an electrocautery delivery system significantly reduce procedure duration and were safe and effective in the management of symptomatic PFCs.

Allergic reaction and metal hypersensitivity after shoulder joint replacement.

PURPOSE: Metal ion release may cause local and systemic effects and induce hypersensitivity reactions. The aim of our study is first to determine if implant-related hypersensitivity correlates to patient symptoms or not; second, to assess the rate of hypersensitivity and allergies in shoulder arthroplasty. METHODS: Forty patients with shoulder replacements performed between 2015 and 2017 were studied with minimum 2-year follow-up; no patient had prior metal implants. Each patient underwent radiographic and clinical evaluation using the Constant-Murley Score (CMS), 22 metal and cement haptens patch testing, serum and urine tests to evaluate 12 metals concentration, and a personal occupational medicine interview. RESULTS: At follow-up (average 45 ± 10.7 months), the mean CMS was 76 ± 15.9; no clinical complications or radiographic signs of loosening were detected; two nickel sulfate (5%), 1 benzoyl peroxide (2.5%) and 1 potassium dichromate (2.5%) positive findings were found, but all these patients were asymptomatic. There was an increase in serum aluminum, urinary aluminum and urinary chromium levels of 1.74, 3.40 and 1.83 times the baseline, respectively. No significant difference in metal ion concentrations were found when patients were stratified according to gender, date of surgery, type of surgery, and type of implant. CONCLUSIONS: Shoulder arthroplasty is a source of metal ion release and might act as a sensitizing exposure. However, patch test positivity does not seem to correlate to hypersensitivity cutaneous manifestations or poor clinical results. Laboratory data showed small constant ion release over time, regardless of gender, type of shoulder replacement and implant used. LEVELS OF EVIDENCE: Level II.

Metal Augments Used in Revision Hip Arthroplasty: A Systematic Review and Single-Arm Meta-Analysis.

BACKGROUND: Porous metal augments are used in complex hip arthroplasty; however, few studies have assessed their efficacy and safety. This systematic review analyzed the use of augments in revision hip arthroplasty and summarized the clinical research findings. METHODS: We used combinations of "revision," "replacement," "arthroplasty," "augment," "acetabular," and "hip" to search PubMed, Web of Science, EMBASE, Cochrane Library databases, and clinical trial registration platform "Clinicaltrials" for relevant literature. The functional score, restoration of hip center of rotation, revision of implants, and complications were analyzed. Patients were divided into 3 subgroups according to the mean follow-up period. Overall, 19 reports involving 647 patients (655 hips) were selected. The mean age at the time of surgery was 63 years (range, 24-106) and the mean follow-up duration was 66 months (range, 11-204). RESULTS: Harris Hip Score increased from approximately a mean of 40 points preoperatively to a mean of 84 points postoperatively. The vertical distance between hip center of rotation and teardrop was restored from a preoperative distance of 41.9 to 21.7 mm postoperatively. The overall acetabular revision rate was 4.7%, and the incidence of complications was 8.2%. There were significant differences in the reoperation, acetabular revision, and complication rates among the subgroups. CONCLUSION: Metal augments used in revision hip arthroplasty are a safe and effective treatment option to correct acetabular defects.

Long-term survival analysis of cementless large-diameter head metal-on-metal total hip arthroplasty.

INTRODUCTION: The aim of this retrospective study was to study the long-term survival and reasons for revisions of a single-type, large-diameter head (LDH) metal-on-metal (MoM) implant. A special study interest was to find the threshold level for revision in terms of adverse reaction to metal debris (ARMD). MATERIALS AND METHODS: In this cohort study, we retrospectively reviewed 234 patients (253 hips) who received 38 mm head size LDH MoM total hip arthroplasties (THAs) between 01 January 2004 and 31 December 2009 at our institution. Patient symptoms, conventional radiographs, magnetic resonance imaging (MRI) findings and whole blood metal ions were studied. RESULTS: The median follow-up time was 11.5 years. The Kaplan-Meier cumulative survival estimate of the implant was 89.6% at 10 years and 82.9% at 14.6 years. Overall, 34/253 (13.4%) hips were revised during the follow-up period and of these; 19/34 (55.9%) were revised due to ARMD. The prevalence of ARMD was 12.4% (29/234 patients). CONCLUSIONS: The survival of the implant was on a moderate level as the 10-year cumulative survival rate was 89.6%. The exact threshold level for ARMD revision cannot be determined due to multiple variables affecting factors in re-operation decision-making.

Contact allergy to metals in metalworkers: A systematic review and meta-analysis.

Occupational hand eczema is frequent in metalworkers. The contribution of metal allergies is poorly elucidated even though such exposures are common at the workplace. To estimate the prevalence of metal allergy to cobalt (Co), chromium (Cr) and nickel (Ni) in metalworkers and compare these to estimates from the European Surveillance System on Contact Allergies (ESSCA). Two authors independently searched PubMed for studies reporting on the prevalence of metal allergy in metalworkers. Proportion meta-analyses were performed to calculate the pooled proportions of metal allergy in metalworkers. In total, 29 studies (22 from Europe) were included yielding 5691 subjects for quantitative analysis. The pooled proportion (95% confidence interval) of Co, Cr and Ni in European metalworkers with dermatitis referred to patch test clinics was 8.2% (5.3%-11.7%), 8.0% (5.1%-11.4%), and 11.0% (7.3%-15.4%), respectively. The corresponding estimates for unselected metalworkers from workplace studies were 4.9% (2.4%-8.1%), 5.2% (1.0%-12.6%), and 7.6% (3.8%-12.6%), respectively. In comparison, the prevalence of metal allergy in 13 382 consecutive European males with dermatitis was 3.9% (3.6%-4.2%), 4.4% (4.1%-4.8%) and 6.7% (6.3%-7.0%) for Co, Cr and Ni, respectively. Data on sex, age, body piercings and atopic dermatitis in metalworkers with metal allergy was mostly lacking. Metal allergy to all three metals was significantly more common in European metalworkers with dermatitis attending patch test clinics as compared to ESSCA data, indicating a relationship to occupational exposures, however, confounders could not be accounted for.