Adverse Local Tissue Reactions Research Articles

Pinnacle Ultamet metal-on-metal total hip arthroplasty survivorship: average 10-year follow-up.

BackgroundIt is unclear whether a connection exists between femoral head size, offset, neck length, and cup abduction angles, and rate of revision in metal-on-metal (MoM) total hip arthroplasty (THA) implant systems.MethodsA retrospective review of MoM THA completed by a single surgeon with a single implant between 2003 and 2008 was conducted. Patient demographics, implant data, radiographs, and revision details were collected at follow-up. Incidence rates for revision and osteolysis were calculated in regard to the femoral head size, stem offset, neck length, and cup abduction angles.ResultsSix hundred and ninety two THAs were identified, with 79% of patients returning for a median follow-up of 10.3 years (interquartile range = 6.0-12.3). The median time to revision was 7.5 years (interquartile range = 5.3-9.9) among 27 total revision surgeries. The overall incidence rate of revision was 5.4 revisions per 1000 person-years, 3.0 revisions per 1000 person-years for adverse local tissue reaction. Hips with a cup abduction angle of ≤40° had revisions at nearly twice the rate of those with an angle of 41°-50° (incidence rate ratio = 1.98, 95% confidence interval: 0.92, 4.29). Hips with a 9 mm neck length had an increased rate of revision (incidence rate ratio = 5.94, 95% confidence interval: 1.33, 26.55) relative to those with a neck length of 0 mm. Rates of osteolysis were similar between implants of different head sizes, neck lengths and cup abduction angles.ConclusionsMoM implant systems with longer necks and smaller cup abduction angles may lead to increased need for revision. Results from this study suggest a need for closer long-term follow-up of MoM THA systems.

New materials for hip and knee joint replacement: What's hip and what's in kneed?

Over the last three decades there have been significant advancements in the knee and hip replacement technology that has been driven by an issue in the past concerning adverse local tissue reactions, aseptic and septic loosening. The implants and the materials we utilize have improved over the last two decades and in knee and hip replacement there has been a decrease in the failures attributed to wear and osteolysis. Despite these advancements there are still issues with patient satisfaction and early revisions due to septic and aseptic loosening in knee replacement patients. This article reviews the state of current implant material technology in hip and knee replacement surgery, discusses some of the unmet needs we have in biomaterials, and reviews some of the current biomaterials and technology that may be able to solve the most common issues in the knee and hip replacement surgery.

Mid-term results of a prospective randomised controlled trial comparing large-head metal-on-metal hip replacement to hip resurfacing using patient-reported outcome measures and objective functional task-based outcomes.

The early outcomes of large head-metal-on-metal total hip arthroplasty (MoM THA) are compromised by adverse local tissue reaction to metal debris. This study is the mid-term follow-up of a prospective randomised control trial (pRCT) comparing MoM THA to MoM HR. We sought to answer whether there was a difference between MoM THA and MoM HR at mid-term follow-up in the implant survival; patient-reported outcome measures (PROMs); and when performing objective functional tasks? A total of 104 patients were studied. Of these 56 had MoM THA (50 male) and 48 had HR (43 male). Mean age at surgery was 52 years in both groups.We reviewed this cohort at mid-term follow-up [minimum 8 years (mean 9 years; range 8-10; SD 0.7)]. PROMs that were completed were OHS, WOMAC, SF-12, and the UCLA. For objective functional task-based outcomes, gait parameters for operated legs were assessed in a subgroup of 17 patients with high UCLA. Revision rate in MoM THA group was 7/56 (12.5%) and in the HR group was 1/48 (2.1%). Overall revision rate at minimum 8-year follow-up was 7.7% (8 of 104 patients). PROMs data comparing MoM THA versus HR showed no difference between the groups. 4 (8.5%) of the non-revised (47) HR patients had WOMAC function or pain score below 70. 3 (6.4%) patients had both pain and function scores <70. In the THA group, 5 (10.2%) of the non-revised (49) patients had WOMAC pain or function scores <70. 3 (6.1%) patients had both pain and function scores <70. The comparison of HA versus THA showed several gait parameters in the HR group to be better but not statistically significant (p > 0.05 Mann-Whitney U-test). At mid-term follow-up, the revision rate of MoM articulation for THA is high (7.7%), being higher in large head MoM total hips versus resurfacing. Overall probability of 10-year survival is 92.3% (KM analysis, 95% for MoM THA and 98% for HR). The HR group had better functional parameters on gait-based tasks compared to THA group but this difference did not reach statistical significance.

Adverse Local Tissue Reaction due to Mechanically Assisted Crevice Corrosion Presenting as Late Instability Following Metal-on-Polyethylene Total Hip Arthroplasty

BackgroundMechanically assisted crevice corrosion (MACC) at modular junctions can cause a spectrum of adverse local tissue reactions (ALTRs) in patients who have undergone total hip arthroplasty (THA). The purpose of this study is to describe the presentation, treatments, and related complications of a cohort of patients presenting with late instability following metal-on-polyethylene THA due to underlying MACC and ALTR. MethodsThis multicenter retrospective case series presents 17 patients (12 women, mean age 62.6, range 42-73) presenting with late instability secondary to ALTR and MACC. All patients had a metal (Cobalt Chrome)-on-polyethylene bearing surface. Patients experienced a mean 2.7 dislocations (range 1-6) at mean 4.3 years (range 0.4-17.0) following their index surgery. Serum metal levels (n = 12) demonstrated a greater elevation of cobalt (mean 6.9, range 0.13-20.88 ng/mL) than chromium (mean 1.9, range 0.13-3.23 ng/mL). ResultsPatients were revised for instability at a mean of 6.8 years (range 2.1-19.4) following their index surgery. ALTR was encountered in every case and the modular head-neck junction demonstrated visible corrosion. An exchange of the CoCr head to a ceramic head with a titanium sleeve and placement of a constrained liner was performed for a majority of patients (n = 15, 88.2%). Five patients (29.4%) had complications postoperatively including peroneal palsy (n = 2), periprosthetic joint infection (n = 2), and ALTR recurrence (n = 1). ConclusionRecurrent instability in the setting of otherwise well-positioned THA components and without another obvious cause should raise concern for ALTR as a potential underlying etiology.

Influence of protein adsorption on tribocorrosion behaviour of CoCrMo biomedical-grade alloys

CoCrMo alloys have been widely used in metal-on-metal hip replacements. They exhibit excellent long-term survival rates; however, recently, high failure rates associated with adverse local tissue reactions have been observed. CoCrMo alloys generally work extremely well; however, sometimes their wear rate is high. This work investigated protein adsorption effects on the tribocorrosion behaviour of CoCrMo biomedical-grade alloys under different surface and media conditions. The study of the wear mechanisms indicated that protein adsorption affects the corrosion and mechanical material loss of the investigated material. The synergistic and antagonistic behaviour of the material was correlated with the protein adsorption.

Improvement of tribocorrosion behavior on titanium alloy by carbide-derived carbon (CDC)

In total hip replacements (THRs), metal-on-metal (MoM) design used to be predominant in the market until 2009 when it has been shown that its wear products could cause several adverse local tissue reactions (ALTR). The leading cause of excessive MoM wear products is the tribocorrosive reaction, which is the synergism of tribology and corrosion. To mitigate this effect, inspired by the presence of tribolayer on retrieved hip implants, carbide-derived carbon (CDC) has been proposed to be a potential solution for the current problem. In this study, we successfully carburized Ti6Al4V alloy and fabricated CDC, which was characterized by X-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM). According to the results of tribocorrosion experiments, CDC specimens presented less potential drop, less wear volume loss and lower friction coefficient in 3.6 k- and 100 k-cycle experiments. The mechanism of CDC's protection was proposed to explain the current data. Meanwhile, CDC's biocompatibility was also examined by cell proliferation and direct observation of stained actins and nuclei in cells by confocal microscopy. Combined with all collected data, it has been concluded that CDC can provide excellent protection to titanium alloy substrate with similar biocompatibility to Ti6Al4V.

Is There an Optimal Cutoff for Aspiration Fluid Volume in the Diagnosis of Periprosthetic Joint Infection?

BackgroundThe diagnosis of periprosthetic joint infection is often challenging in the setting of low aspiration volumes, or in the presence of infection with a slow-growing organism. We sought to determine if an optimal threshold of aspiration fluid volume exists when cultures from the preoperative aspiration are compared to intraoperative cultures. MethodsAll revision total hip and knee arthroplasty procedures over 5 years at our institution were reviewed. Cases were excluded if they underwent joint lavage during aspiration, had an antibiotic spacer in place, were suspected of adverse local tissue reaction to metal debris, did not have an accurate aspiration volume recorded, or if there were no aspiration or operative cultures available. Receiver operating characteristic curves were used to evaluate aspiration volume for identifying cases with identical aspiration and culture results. ResultsA total of 857 revision cases were reviewed, among which 294 met inclusion criteria. There were 45 cases (15.3%) with discordant aspiration and operative cultures. The mean aspiration volume for identical cases was significantly higher than for discordant cases (19.1 vs 10.2 mL, P = .02). The proportion of slow-growing organisms was significantly greater among discordant compared to identical operative cultures (52.4% for discordant cases vs 8.2% for identical cases, P < .001). The optimal cutoff value for predicting identical cultures was 3.5 mL for typical organisms and 12.5 mL for slow-growing organisms. ConclusionAspiration cultures are more likely to correlate with intraoperative cultures with higher aspiration volumes, and the optimal aspiration volume is higher for slow-growing organisms.

Standardizing terms for tribocorrosion-associated adverse local tissue reaction in total hip arthroplasty.

Recognizing and adopting standardized terms for adverse local tissue reaction associated with tribocorrosion in total hip arthroplasty are essential for clear scientific discourse and clinical communication. Our goal was to develop terms that can be broadly applied to characterize the local tissue response to tribocorrosion debris, based on current evidence regarding the etiology of this failure mode and its consequences. The proposed standardized terms will improve the understanding and interpretation of analytical tests, advance diagnostic and treatment algorithms, and reduce confusion in research by maintaining consistent nomenclature.

Clinical Results of Revision Hip Arthroplasty for Neck-Taper Corrosion and Adverse Local Tissue Reactions Around a Modular Neck Stem

BackgroundAdverse local tissue reactions (ALTRs) around a modular neck stem at our institution lead to a 13.5% rate of revision. The purpose of this study was to report the clinical results of revision total hip arthroplasty (THA) in this patient population. MethodsWe identified 80 hips in 77 patients who underwent revision THA due to neck-stem corrosion. Intraoperative and postoperative complications, clinical outcomes, re-revision rates, and the postoperative ion levels were recorded. ResultsThe mean follow-up period after revision was 45.3 ± 16.3 months (range 24-81 months). There were no intraoperative mechanical complications during the revision surgery. Eight hips (10%) had postoperative complications related to the revision implant, of which 6/8 came to re-revision: postoperative implant dislocation in 4 hips—2 treated nonsurgically, aseptic loosening of femoral component in 2 hips, and periprosthetic femoral fracture in 2 hips. No patients had recurrence of ALTR nor the recurrence of groin pain within the follow-up period. With 2 exceptions, ion levels normalized within one year of the revision surgery. The survival rate was 94% (95% confidence interval 84-98) at 32 months and 82% (95% confidence interval 56-93) at 63 months after revision THA (using re-revision THA due to any reason as the endpoint). ConclusionIntraoperative complication, postoperative complication, and re-revision rates are equivalent to femoral revision surgeries for other causes (infection, fracture, loosening). We recommend selecting revision-type stems to minimize the risk of femoral loosening or periprosthetic fracture, and larger femoral heads or dual mobility bearings to minimize the risk of dislocation.

Specimen-Specific Finite Element Models for Predicting Fretting Wear in Total Hip Arthroplasty Tapers.

Products from fretting wear and corrosion in the taper junction of total hip arthroplasty (THA) devices can lead to adverse local tissue reactions. Predicting damage as a function of design parameters would aid in the development of more robust devices. The objectives of this study were to develop an automated method for identifying areas of fretting wear on THA taper junctions, and to assess the predictive ability of a finite element model to simulate fretting wear in THA taper junctions. THA constructs were fatigue loaded, thus inducing damage on the stem taper. An automated imaging and analysis algorithm quantified fretting wear on the taper surfaces. Specimen-specific finite element models were used to calculate fretting work done (FWD) at the taper junction. Simulated FWD was correlated to imaged fretting wear. Results showed that the automated imaging approach identified fretting wear on the taper surface. Additionally, finite element models showed the greatest predictive ability for tapers exhibiting distal contact. Finite element models predicted an average of 30.3% of imaged fretting wear. With additional validation, the imaging and finite element techniques may be useful to manufacturers and regulators in the development and review of new THA devices.

Outcome of Re-Revision Surgery for Adverse Local Tissue Reaction in Metal-on-Polyethylene and Metal-on-Metal Total Hip Arthroplasty

BackgroundAdverse local tissue reactions (ALTRs), initially described as a complication of metal-on-metal (MoM) total hip arthroplasty (THA), have also become an important risk factor for implant failure requiring revision surgery in metal-on-polyethylene (MoP) THA due to modular taper corrosion. This study aims to report early complication rates and outcomes as well as potential risk factors for a re-revision. MethodsA total of 252 consecutive THA patients who underwent revision for ALTR were reviewed. There were 40 patients (16%) who underwent a second revision: (1) 26 MoP patients with modular taper corrosion and (2) 14 MoM patients. Patient demographics as well as clinical information were analyzed. Binary logistic regression was used to test for associations between re-revision surgery and clinical parameters. ResultsThe overall complication rate following initial revision for ALTR was 21%. Sixteen percent of these revision patients required a re-revision. The most common indication for re-revision was dislocation (45%). The complication rate was 35% following a re-revision which included dislocation (36%), infection (36%), fracture (14%), and implant loosening (14%). The rate of patients requiring a third revision was 23% with the most common indications being dislocation (33%) and infection (33%) (P = .032). ConclusionHigh rate of early complications (35%) and third revisions (23%) were observed following re-revision of symptomatic ALTR patients with those requiring re-revision associated with extensive intraoperative tissue necrosis. These findings provide clinically useful information that may assist surgeons in clinical decision making and preoperative counseling of both MoM and MoP patients undergoing re-revision surgery for ALTR.

How to Interpret Metal Ions in THA

BackgroundModern total hip arthroplasty has seen an unfortunate increase in proportional implant failures secondary to adverse local tissue reactions (ALTRs) secondary to wear of metal-on-metal (MoM) bearings and mechanically assisted crevice corrosion (MACC) related to corrosion at implant junctions and tapers. The purpose of this study is to describe the appropriate choice of metal ion testing and evaluation of those levels to identify failed total hip arthroplasty implants containing cobalt and chromium. MethodsWhen presented with an arthroplasty of concern, the surgeon must determine what metal ion levels to obtain and then incorporate those levels into a treatment algorithm. Patients with painful hip arthroplasties are evaluated for chromium and cobalt by obtaining whole blood and synovial metal levels. ResultsSynovial fluid cobalt had the highest correlation with ALTR compared with the other tests, with a threshold of 19.75 ng/ml, with a specificity of 89%, if the cobalt-to-chromium ratio is greater than 1.4 ng/ml in a metal on polyethylene hip, with a sensitivity of 95%. ConclusionThe interpretation of whole blood metal ions is a key component of the algorithm in treating the symptomatic hip arthroplasty but is not to be used in a vacuum.

What Surgeons Need to Know About Adverse Local Tissue Reaction in Total Hip Arthroplasty

Adverse local tissue reactions (ALTRs) were first associated with patients with failed metal-on-metal surface replacements and total hip arthroplasty (THA). However, an increasing number of cases of ALTR in metal-on-polyethylene (MOP) THA patients is being reported. Clinically, ALTR appears as benign, aseptic masses or bursae in the periprosthetic tissues. Histopathologically, ALTRs are distinguished by an intense lymphocyte infiltrate, destruction of the synovial surfaces, widespread necrosis, and fibrin exudate. Tribocorrosion of modular junctions appears to be the cause of ALTR in MOP patients. The various tribocorrosion damage modes occurring at modular junctions produce metal ions and a diversity of particulates in relation to size, chemical composition, and structure. The mechanisms by which these various products of tribocorrosion lead to ALTR are still a matter of considerable research. This review clarifies what constitutes ALTR, its relationship to implant factors, and highlights current methods for diagnosis and management of patients with ALTR in the setting of MOP THA.

How Useful Is Magnetic Resonance Imaging in Evaluating Adverse Local Tissue Reaction?

Biologic failures of hip arthroplasty have emerged as an increasing threat to the longevity of the prosthesis. While wear of modern-day bearings has been greatly reduced with the advent of cross-linked polyethylene, local reaction to metal particles either from the bearing itself or to any of the modular tapers appears to be on the rise. Monitoring of these reactions by the use of plain radiographs or serum markers appears to be insufficient to gauge the gravity of the response.Over the past decade, the use of magnetic resonance imaging (MRI) techniques has emerged as the superior noninvasive instrument to assess the extent of soft tissue reaction around hip implants. The use of MRI around implants was initially challenging due to the presence of relatively high ferrous metals especially cobalt which causes local distortion of the magnetic fields. Novel changes in pulse sequencing have greatly improved the sensitivity and specificity of MRI so that at this time, MR is the most predictive diagnostic tool in evaluating the extent of tissue destruction. We feel strongly that modern MRI techniques are the most important tool in the workup of the patient suspected of having an adverse tissue reaction after hip arthroplasty.

Adverse Local Tissue Reactions in Total Hip Arthroplasty: Who, When, and How to Revise

Adverse local tissue reaction (ALTR) has initially been described as a complication in metal-on-metal total hip arthroplasty (THA) [ 1 Kwon Y.-M. Glyn-Jones S. Simpson D.J. Kamali A. McLardy-Smith P. Gill H.S. et al. Analysis of wear of retrieved metal-on-metal hip resurfacing implants revised due to pseudotumours. J Bone Joint Surg Br. 2010; 92: 356-361https://doi.org/10.1302/0301-620X.92B3.23281 Crossref PubMed Scopus (185) Google Scholar , 2 Kwon Y.-M. Fehring T.K. Lombardi A.V. Barnes C.L. Cabanela M.E. Jacobs J.J. Risk stratification algorithm for management of patients with dual modular taper total hip arthroplasty: consensus statement of the American Association of Hip and Knee Surgeons, the American Academy of Orthopaedic Surgeons and the Hip Society. J Arthroplasty. 2014; 29: 2060-2064https://doi.org/10.1016/j.arth.2014.07.029 Abstract Full Text Full Text PDF PubMed Scopus (64) Google Scholar , 3 Liow M.H.L. Kwon Y.-M. Metal-on-metal total hip arthroplasty: risk factors for pseudotumours and clinical systematic evaluation. Int Orthop. 2017; 41: 885-892https://doi.org/10.1007/s00264-016-3305-1 Crossref PubMed Scopus (37) Google Scholar , 4 Kwon Y.-M. Cross-sectional imaging in evaluation of soft tissue reactions secondary to metal debris. J Arthroplasty. 2014; 29: 653-656https://doi.org/10.1016/j.arth.2014.02.007 Abstract Full Text Full Text PDF PubMed Scopus (20) Google Scholar , 5 MacDonald S.J. Brodner W. Jacobs J.J. A consensus paper on metal ions in metal-on-metal hip arthroplasties. J Arthroplasty. 2004; 19: 12-16https://doi.org/10.1016/j.arth.2004.09.009 Abstract Full Text Full Text PDF PubMed Scopus (131) Google Scholar ]. However, there have recently been increasing concerns regarding the occurrence of ALTR in metal-on-polyethylene THA due to corrosion at the head-neck taper junction in a process described as mechanically assisted crevice corrosion [ [6] Jacobs J.J. Gilbert J.L. Urban R.M. Corrosion of metal orthopaedic implants. J Bone Joint Surg Am. 1998; 80: 268-282https://doi.org/10.2106/00004623-199802000-00015 Crossref PubMed Scopus (743) Google Scholar ]. The generation of biologically active, nanometer-sized metal particles and metal ions from the arthroplasty bearing surfaces and taper junctions has been associated with the occurrence of localized, adverse periprosthetic soft tissue response, which has been recently recognized as an important emerging mode of failure in THA patients [ 7 Liow M.H.L. Urish K.L. Preffer F.I. Nielson G.P. Kwon Y.-M. Metal ion levels are not correlated with histopathology of adverse local tissue reactions in taper corrosion of total hip arthroplasty. J Arthroplasty. 2016; 31: 1797-1802https://doi.org/10.1016/j.arth.2016.01.041 Abstract Full Text Full Text PDF PubMed Scopus (28) Google Scholar , 8 Kwon Y.-M. MacAuliffe J. Arauz P.G. Peng Y. Sensitivity and specificity of metal ion level in predicting adverse local tissue reactions due to head-neck taper corrosion in primary metal-on-polyethylene total hip arthroplasty. J Arthroplasty. 2018; 33: 3025-3029https://doi.org/10.1016/j.arth.2018.04.007 Abstract Full Text Full Text PDF PubMed Scopus (30) Google Scholar , 9 Cooper H.J. Urban R.M. Wixson R.L. Meneghini R.M. Jacobs J.J. Adverse local tissue reaction arising from corrosion at the femoral neck-body junction in a dual-taper stem with a cobalt-chromium modular neck. J Bone Joint Surg Am. 2013; 95: 865-872https://doi.org/10.2106/JBJS.L.01042 Crossref PubMed Scopus (296) Google Scholar , 10 Vendittoli P.-A. Roy A. Mottard S. Girard J. Lusignan D. Lavigne M. Metal ion release from bearing wear and corrosion with 28 mm and large-diameter metal-on-metal bearing articulations: a follow-up study. J Bone Joint Surg Br. 2010; 92: 12-19https://doi.org/10.1302/0301-620X.92B1.22226 Crossref PubMed Scopus (100) Google Scholar , 11 Seon J.-K. Park J.-K. Shin Y.-J. Seo H.-Y. Lee K.-B. Song E.-K. Comparisons of kinematics and range of motion in high-flexion total knee arthroplasty: cruciate retaining vs. substituting designs. Knee Surg Sports Traumatol Arthrosc. 2011; 19: 2016-2022https://doi.org/10.1007/s00167-011-1434-z Crossref PubMed Scopus (51) Google Scholar ]. At the 2019 Annual Meeting of American Association of Hip and Knee Surgeons, the symposium on ALTRs with particular focus on “who, when, and how to revise” patients with ALTR was presented. The objectives of this symposium were to summarize clinical challenges in optimizing patient evaluation and revision surgery outcome. Specifically, the symposium presentations highlighted that there is a spectrum of clinical presentations of ALTRs due to taper corrosion and metal bearing surface wear, reflecting a complex interplay of implant, surgical, and patient factors. The current state of knowledge on the importance of various taper material combinations and taper design geometry on taper corrosion is evolving. A systematic risk stratification approach based on currently available data is critical in optimizing evaluation and revision surgery indications. The utility and limitations of specialized diagnostic tests including metal ion levels and cross-sectional imaging studies such as metal artifact reduction sequence magnetic resonance imaging in the clinical decision-making process is important in evaluation of these patients. Furthermore, optimizing revision surgery outcome for ALTRs involves careful preoperative planning, implant selection, and surgical techniques to overcome challenges associated with soft tissue necrosis.

In vitro evaluation of human myoblast function after exposure to cobalt and chromium ions.

The replacement of a native hip joint by a metal-on-metal prosthesis may induce deleterious inflammatory side effects that are associated with the release of wear particles and metal ions. These events are referred to the adverse reaction to metal debris (ARMD) and the adverse local tissue reaction (ALTR). While wear particles seem involved in ARMD, the role of metal ions in ALTR and their impact on myoblasts, located in the prosthesis vicinity, has not been fully identified. To clarify this issue we investigated, using an in vitro culture system, the effect of cobalt and/or chromium ions (Co2+ and/or Cr3+ ) on human myoblast proliferation, cellular differentiation, and inflammatory marker expression. Freshly isolated human myoblasts were cultured in media supplemented with graded concentrations of Co2+ and/or Cr3+ . Co2+ induced a concentration-dependent decrease of both myoblast viability and myogenic differentiation while Cr3+ did not. Co2+ or Co2+ /Cr3+ also induced the upregulation of ICAM-1, whereas HLA-DR expression was unaffected. Moreover, allogenic monocytes induced the synergistic increase of Co2+ -induced ICAM-1 expression. We also found that Co2+ stabilized HIF-1α and increased TLR4, tumor necrosis factor-alpha (TNF-α), and interleukin 1β (IL-1β) expression in a dose and time-dependent manner in human myoblasts. This study showed that Co2+ , but not Cr3+ , was toxic toward myoblasts and induced, in the surviving cells, expression of inflammatory markers such as ICAM-1, TLR4, TNF-α, and IL-1β. This suggests that Co2+ , most efficiently in the presence of monocytes, may be a key inducer of ALTR, which may, if severe and long-lasting, eventually result in prosthesis loosening.

Accolade TMZF trunnion corrosion and mechanical failure 9 yr after primary surgery: A case report and treatment options

Accolade TMZF trunnion corrosion and mechanical failure 9 yr after primary surgery: A case report and treatment options

Progression of adverse local tissue reaction in ASR metal-on-metal hip arthroplasty: a longitudinal MARS-MRI study at mid- to long-term.

Despite the large number of studies assessing adverse local tissue reaction (ALTR) in metal-on-metal (MoM) hip implants, there is still a lack of knowledge about the natural progression of ALTR. The aims of this study were to describe the natural course of changes in ALTR at mid- to long-term follow-up for patients treated with metal-on-metal hip arthroplasty and to determine possible risk factors associated with change in ALTR. A total of 158 patients (158 hips), 109 MoM hip resurfacing arthroplasties (HRAs) and 49 MoM total hip arthroplasties (THAs), with 2 clinical follow-ups including MARS-MRIs were included. The mean time from index operation to the first visit was 7.6 years (range 3.4-11.4 years), and the mean time between the 2 visits was 1.0 year (range 0.7-1.6 years). The proportion of patients with moderate or severe ALTR did not increase significantly between the first and second visit for the MoM HRA group (14.7-15.6%; p = 0.850) or the MoM THA group (32.7-36.7%; p = 0.671). 8 (7.3%) HRA patients and 9 (18.4%) THA patients progressed in ALTR grade. None of the collected clinical variables was sensitive or specific in identifying patients with ALTR progression. Although ALTR prevalence was high in our cohort, clinically significant ALTR progression was rare. We were unable to find any predictors associated with ALTR change. This indicates that MARS-MRI remains a valuable tool in the follow-up of patients treated with MoM hip devices in identifying patients who may need revision surgery.

Cobalt and Chromium Ion Release in Metal-on-Polyethylene and Ceramic-on-Polyethylene THA: A Simulator Study With Cellular and Microbiological Correlations

BackgroundThe aims of this study were to determine the levels of cobalt (Co) and chromium (Cr) ions generated in simulators from metal-on-polyethylene (MoP) and ceramic-on-polyethylene (CoP) constructs. Furthermore, we aimed to investigate the cytotoxic effect of these ion levels on native tissues and their potential to modify periprosthetic joint infection risk. MethodsWe used in vitro culture of human adipose-derived mesenchymal stem cells (AMSCs) and Staphylococcus epidermidis cultures, respectively. Ten hip simulator constructs (5 MoP and 5 CoP) were assembled and run for 1,000,000 cycles in bovine serum and evaluated for CoCr concentration. Cytotoxicity and growth impact on AMSCs and S. epidermidis was compared between CoCr and inert silicon dioxide. ResultsAfter 1,000,000 cycles, mean MoP and CoP Co concentration was 2264 and 0.6 ng/mL, respectively (P < .001). Mean MoP and CoP Cr concentration was 217 and 4.3 ng/mL, respectively (P < .001). Mean MoP Co:Cr ratio was 10:1. Co ions were significantly more toxic to human AMSCs than control silicon dioxide in a dose-response manner (P < .001). S. epidermidis growth was not significantly impacted by Co concentrations observed in the simulators. ConclusionMoP constructs built in ideal conditions generated substantial CoCr debris, highlighting a baseline risk with these implants that may be exacerbated by host factors or imperfect surgical technique. Evaluation of impact on AMSCs suggests that debris levels produced under simulator conditions can be cytotoxic. In addition, these concentrations did not potentiate or inhibit S. epidermidis growth, suggesting that elevated periprosthetic joint infection rates with adverse local tissue reaction are related to other factors potentially associated with tissue necrosis.

Recent Progress on Mg- and Zn-Based Alloys for Biodegradable Vascular Stent Applications

Currently, biodegradable metals for implantation applications are widely investigated to replace biodegradable polymeric implantations, which may cause inflammatory or adverse local tissue reactions. Amongst these metals, magnesium (Mg) and zinc (Zn) alloys with good biocompatibility, mechanical properties, and corrosion resistance are being widely investigated. In this review, the criteria for biodegradable vascular stents, and the advantages and limitations of biodegradable Mg and Zn vascular stents, are summarized and evaluated. By summarizing and discussing recent research on Mg- and Zn-based alloys used as biodegradable vascular stents, this review considered many alloys that can potentially serve as biodegradable vascular stents and suggests future research directions for the development of Mg- and Zn-based alloys as biodegradable metal stents.