MARS MRI Characteristics of Adverse Local Tissue Reactions in Taper Corrosion of Metal-On-Polyethylene THA Differ From Metal-On-Metal THA

BackgroundMetal artifact reduction sequence (MARS) magnetic resonance imaging (MRI) has been recommended as a cross-sectional imaging modality in clinical evaluation of adverse local tissue reactions (ALTRs) in metal-on-metal (MoM) patients and metal-on-polyethylene (MoP) patients with taper corrosion. The aim of the study was to compare MARS MRI characteristics of ALTR in MoM total hip arthroplasty (THA) with ALTR in MoP THA with modular taper corrosion.MethodsA total of 197 patients with ALTR were evaluated: 86 patients with MoM THA; 37 MoP patients with head-neck taper corrosion; and 74 MoP patients with neck-stem dual taper corrosion. MARS MRI scans were evaluated to identify location, size, type of ALTR (I-III), and associated ALTR synovitis (cystic, solid, and mixed).ResultsMARS MRI characteristics of ALTR were significantly different between the MoM and MoP groups (P = .017). The MoP group demonstrated the highest proportion of thick-walled cystic masses type II (56.7% in head-neck taper corrosion MoP and 46.5% in dual taper corrosion MoP vs 28.7% in MoM), whereas the MoM group had the highest proportion of thin-walled cystic masses type I. MoM implants (96.8%) were significantly more likely to have ALTR in multiple locations compared with both MoP groups (P = .001).ConclusionThis study demonstrates that MARS MRI characteristics of ALTR differ by bearing type with a significantly higher percentage of mixed type and solid type ALTR in the taper corrosion MoP THA compared with MoM THA. This information provides clinically useful information in evaluation of symptomatic MoP and MoM THA patients for ALTRs.     

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

Although ‘dual taper’ modular stems with interchangeable modular necks have the potential to optimize hip biomechanical parameters, there is increasing concern regarding the occurrence of adverse local tissue reactions from mechanically assisted crevice corrosion at the neck–stem taper junction. A systematic treatment approach (risk stratification algorithm) based on the currently available data is recommended to optimize patient management. While specialized tests such as metal ion analysis and MARS MRI are useful modalities in evaluating for adverse tissue reactions, over-reliance on any single investigative tool in the clinical decision-making process should be avoided. There should be a low threshold to perform a systematic evaluation of patients with dual taper stem total hip arthroplasty as early recognition and diagnosis will facilitate the initiation of appropriate treatment.     

Case Studies in Management of THA Failure Secondary to Taper Corrosion,Modular Junctions and Metal-on-Metal Bearings

The diagnosis and treatment of patients with painful total hip arthroplasties secondary to taper corrosion and wear of modular junctions and metal-on-metal bearings represents a major challenge for the orthopaedic clinician. Guidelines are evolving as we analyze the growing body of evidence regarding metal-related failures of orthopaedic implants and adverse reactions to metal debris. In this article 6 case examples are presented to enhance understanding and application of current evidence into practice. Clinical expertise is integrated with the best available evidence from research and national joint registries data into the decision making process relevant for patient care in everyday practice. Issues addressed include understanding taper corrosion and metal failure mechanisms, clinical presentation of adverse soft tissue reactions, utility of specialized tests such as metal ion analysis and cross-sectional imaging studies, the utility of modular components for primary THA, dealing with recalled component, and current recommendations.     

MRI does not detect acetabular osteolysis around metal-on-metal Birmingham THA

Objective

Osteolysis has not been recognized as a common failure mode of the Birmingham modular metal-on-metal (MoM) total hip arthroplasty (THA). The clinical value of metal artifact reduction sequence (MARS) magnetic resonance imaging (MRI) to assess the periprosthetic soft tissue is well documented; however, the appropriate image modalities to detect periacetabular osteolysis remain unclear.

Case summary

Eleven patients with periacetabular osteolysis within 3–6 years after uncemented Birmingham modular MoM THA with a synergy stem are presented. All 11 patients received corresponding standardized AP pelvis radiographs, high-quality MARS MRIs and CT scans with a metal artifact reduction sequence. While periacetabular osteolysis around MoM THA was not detected on MARS MRI in ten patients, CT imaging identified osteolysis in all patients. Periacetabular osteolysis appears to be a failure mechanism of the Smith & Nephew Birmingham MoM THA.

Discussion

There is no evidence in the literature to support the effectiveness of MARS MRI to detect periacetabular osteolysis around cobalt chromium alloy metal-on-metal total hip arthroplasties. Osteolysis due to corrosion-related particles seems to be one of the primary modes of failure in modular MoM THA.

Conclusions

MRI is not a sensitive test to identify periacetabular osteolysis. The authors recommend CT for the screening of implants with this failure mode. Our study suggests that patients with a Birmingham modular MoM THA are at increased risk to develop acetabular osteolysis and should be carefully monitored for this failure mode.     

Cobalt Levels and Pseudotumor Characteristics Vary due to Metal Ion Source: Modular Femoral Neck vs Metal-on-Metal Articulations

BackgroundThis study examines cobalt levels and pseudotumor characteristics in a non-recalled modular femoral prosthesis. We sought to determine relationships between serum cobalt levels and pseudotumors following modular and metal-on-metal (MoM) total hip arthroplasty (THA), the location and size of pseudotumors, and changes to pseudotumor grade over time.MethodsWe retrospectively evaluated a cohort of 190 primary THAs implanted with a dual-modular femoral stem by one surgeon from 2005 to 2013. One hundred seventeen THAs used a cobalt-chromium modular neck (CoCrMN) component and non-MoM articulation, 63 THAs had a titanium neck component and MoM articulation, and 10 had a titanium neck component and polyethylene liner. Serum ion levels were recorded for all patients. Pseudotumor grade and location were measured by musculoskeletal-trained radiologists.ResultsCobalt levels did not correlate to time after index arthroplasty. In the CoCrMN group, cobalt levels were elevated in 11 of 19 (57.9%) patients with pseudotumor compared to 14 of 19 (73.7%) in the MoM group. Pseudotumors were more often located lateral to the hip joint in the CoCrMN group compared to anteromedial following MoM arthroplasty. In CoCrMN THAs, pseudotumors were visualized in 12 of 51 (23.5%) initial MARS MRIs within 40 months compared to 5 of 66 (7.6%) performed later (P = .02).ConclusionPseudotumor characteristics differ between patients with CoCrMN designs vs those with an MoM articulation. Normal serum cobalt levels did not exclude the presence of a pseudotumor and routine MARS MRI should be included in follow-up of patients with this CoCrMN prostheses.     

What Are the Advantages and Disadvantages of Imaging Modalities to Diagnose Wear-related Corrosion Problems?

Background

Adverse tissue reactions are known to occur after total hip arthroplasty using both conventional and metal-on-metal (MoM) bearings and after MoM hip resurfacing arthroplasty (SRA). A variety of imaging tools, including ultrasound (US), CT, and MRI, have been used to diagnose problems associated with wear after MoM hip arthroplasty and corrosion at the head-trunnion junction; however, the relative advantages and disadvantages of each remain a source of controversy.

Questions/purposes

The purposes of this review were to evaluate the advantages and disadvantages of (1) US; (2) CT; and (3) MRI as diagnostic tools in the assessment of wear-related corrosion problems after hip arthroplasty.

Methods

A systematic literature review was performed through Medline, EMBASE, Scopus CINAHL, and the Cochrane Library without time restriction using search terms related to THA, SRA, US, CT, MRI, adverse tissue reactions, and corrosion. Inclusion criteria were Level I through IV studies in the English language, whereas expert opinions and case reports were excluded. The quality of included studies was judged by their level of evidence, method of intervention allocation, outcome assessments, and followup of patients. Four hundred ninety unique results were returned and 40 articles were reviewed.

Results

The prevalence of adverse local tissue reactions in both asymptomatic and symptomatic patients varies based on the method of evaluation (US, CT, MRI) and imaging protocols. US is accessible and relatively inexpensive, yet has not been used to report synovial thicknesses in the setting of wear-related corrosion. CT scans are highly sensitive and provide information regarding component positioning but are limited in providing enhanced soft tissue contrast and require ionizing radiation. MRI has shown promise in predicting both the presence and severity of adverse local tissue reactions but is more expensive.

Conclusions

All three imaging modalities have a role in the assessment of adverse local tissue reactions and tribocorrosion after total hip arthroplasty. Although US may serve as a screening technique for the detection of larger periprosthetic collections, only MRI has been shown to predict the severity of tissue destruction found at revision and correlate to the degree of tissue necrosis at histologic evaluation.     

The Surgical Options and Clinical Evidence for Treatment of Wear or Corrosion Occurring With THA or TKA

Background

Wear and corrosion occurring in patients with hip and knee arthroplasty are common causes of failure leading to revision surgery. A variety of surgical approaches to these problems have been described, with varying efficacy. Polyethylene wear, metal-on-metal (MoM) hip bearing wear, and problems associated with modular taper corrosion are the areas of greatest clinical impact; results of revisions for these problems are likely to dictate a large portion of revision resources for the foreseeable future, and so they call for specific study.

Questions/purposes

We identified the most frequently reported procedures to treat hip polyethylene wear, knee polyethylene wear, MoM wear after THA, and modular taper corrosion and determined the timing and reasons these failed.

Methods

We performed systematic reviews of the published literature on the four topics using MEDLINE^® and Embase in October 2013; searches were supplemented by hand searches of bibliographies. Prespecified criteria resulted in the identification of 38 relevant articles, of which 33 were either case reports or Level IV evidence. Followup was generally at short term and ranged from 0.2 to 8 years.

Results

The most frequently reported procedures for treating clinically important wear were a partial or complete revision. When treating polyethylene wear, the more frequently reported reasons for hip and knee rerevisions were loosening, continued wear, and instability. Soft tissue reactions were more common and occasionally extensive in patients with MoM or modular taper corrosion. Patients with soft tissue reactions had more complications and higher rerevision rates.

Conclusions

Studies with longer followup and higher levels of evidence are needed to direct the treatment of wear and corrosion. When soft tissue damage secondary to MoM wear or taper corrosion is present, the results of treatment can be poor. There is an urgent need to better understand these two mechanisms of failure.     

Evaluation and treatment of painful total hip arthroplasties with modular metal taper junctions

Modern primary total hip arthroplasty femoral components have evolved to include modular necks. Subsequently, the additional taper junction provides another interface as a potential source for mechanically assisted crevice corrosion, which is a complex process involving fretting and crevice corrosion. Furthermore, it is becoming evident that an adverse local tissue reaction may result in some patients due to the mechanically assisted crevice corrosion. This article details the clinical, radiographic, and laboratory evaluation of patients with these components who present with persistent pain. The relevant surgical strategies and techniques to address this pathology in symptomatic patients are addressed.     

Sensitivity and Specificity of Metal Ion Levels in Predicting “Pseudotumors” due to Taper Corrosion in Patients With Dual Taper Modular Total Hip Arthroplasty

Background

Currently, no serum metal ion threshold exists to identify adverse tissue reactions in total hip arthroplasty (THA) patients with taper corrosion. Our study aims to investigate the sensitivity and specificity of serum metal ions in detecting taper corrosion related pseudotumors in patients with dual taper modular THA.

MRI investigations in patients with problems due to metal-on-metal implants

Until recently, metal-on-metal (MoM) hip implants were commonly used for joint replacement and resurfacings. Their use has rapidly declined following reports of Frühversagen and soft tissue disease caused by the release of metal debris from the prosthesis. Detection of these soft tissue lesions has proven difficult using conventional imaging techniques and blood metal ion tests. Current guidelines recommend the use of imaging modalities including metal artefact reduction sequence (MARS) magnetic resonance imaging (MRI), computed tomography and ultrasound but provide little indication which is best. MARS significantly reduces the susceptibility artefact induced by the presence of metal objects, thereby producing diagnostic quality images that can be shared with other physicians and compared over time. The clinical interpretation of MRI findings of solid pseudotumours and severe muscle atrophy is straightforward: revision is usually recommended. However, the most common MRI findings are of a cystic pseudotumour and minor muscle wasting. In these cases decision-making is difficult and we currently use multi-disciplinary and multi-colleague based meetings to make decisions regarding patient management. This article presents a comparison of imaging modalities and an update on the interpretation of MARS MRI for the investigation of patients with MoM hip implants. The English full-text version of this article is available at Springer Link (under “Supplemental”).     

Enhanced wear and corrosion in modular tapers in total hip replacement is associated with the contact area and surface topography

Widespread concern exists about adverse tissue reactions after metal‐on‐metal (MoM) total hip replacement (THR). Concerns have also been expressed with wear and corrosion of taper junctions in THR. We report the effect of surface finish and contact area associated with a single combination of materials of modular tapers. In an in vitro test, we investigated the head/neck (CoCrMo/Ti) interface of modular THRs using commercially available heads. Wear and corrosion of taper surfaces was compared following a 10 million loading cycle. Surface parameters and profiles were measured before and after testing. Electrochemical static and dynamic corrosion tests were performed under loaded and non‐loaded conditions. After the load test, the surface roughness parameters on the head taper were significantly increased where the head/neck contact area was reduced. Similarly, the surface roughness parameters on the head taper were significantly increased where rough neck tapers were used. Corrosion testing showed breaching of the passive film on the rough but not the smooth neck tapers. Thus, surface area and surface finish are important factors in wear and corrosion at modular interfaces. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:2032–2039, 2013     

Retrieval Analysis of Large-Head Modular Metal-on-Metal Hip Replacements of a Single Design

Background

There are limited publications examining modular metal-on-metal (MoM) total hip implants in which a comprehensive analysis of retrieved components is performed. This study examines 24 retrieved modular MoM implants from a single manufacturer and compares retrieval analytics; bearing surface damage, wear, and modular taper corrosion against patient, surgical and implant characteristics to elucidate significant associations.

Taper Corrosion in Modular Hip Prostheses : Analysis of Serum Metal Ions in 19 Patients

Recently, concerns have been raised about the use of metal-on-metal (MoM) implants. This has led to the recall of several resurfacing and large-diameter total hip arthroplasties (THA). Any MoM interface can be the cause of metal debris and adverse tissue reactions. We analyzed serum metal ions and HOOS scores in 19 of 306 patients treated with a THA with modular neck section. The only MoM interface in this particular implant is the taper between the neck and the stem. The articulating surface consists of a ceramic-on-polyethylene or ceramic-on-ceramic interface. As such, this study looks at the metal ion production from the modular neck section. One of 306 implants needed revision at 52-month follow-up because of an adverse reaction to metal debris (ARMD).     

Revision total hip arthroplasty for metal-on-metal failure

Metal-on-metal (MoM) arthroplasty systems became popular in the early-2000s due to presumed advantages of improved wear characteristics and superior stability. However, subsequent reports of abnormal soft-tissue reactions to MoM implants and national registry data reporting high failure rates raised concerns. Early outcomes of revision total hip arthroplasty (THA) for adverse reaction to metal debris (ARMD) were poor, leading to development of surveillance programs and a trend towards early revision surgery. Patients with MoM arthroplasties require surveillance, comprehensive history and physical examination, imaging with ultrasound or magnetic resonance imaging (MRI), and laboratory evaluation including metal ion levels. Operative strategies for revision THA vary from exchange of modular components to extensive debridement and reconstruction with revision components. Surgeons should be aware of the increased risks of dislocation and infection following revision THA for ARMD. However, there is growing evidence that early revision surgery prior to extensive soft tissue destruction results in improved outcomes and decreased re-operation rates. It is estimated that >1 million MoM articulations have been implanted, with a large proportion still in situ. It is imperative to understand the aetiology, presentation, and management strategies for these patients to optimise their clinical outcomes.     

Comparison of Pre-Revision Magnetic Resonance Imaging and Operative Findings in Mechanically Assisted Crevice Corrosion in Symptomatic Metal-on-Polyethylene Total Hip Arthroplasties

Background

Failed total hip arthroplasty (THA) caused by mechanically assisted crevice corrosion (MACC) has serious consequences—notably, adverse local tissue reactions. Metal artifact reduction sequence (MARS) magnetic resonance imaging (MRI) has been used to evaluate failed THA for other reasons but has not been assessed for the analysis of cases of MACC in the setting of metal-on-polyethylene arthroplasties.

Sensitivity and Specificity of Serum and Synovial Fluid Markers in Diagnosis of Infection in Head-Neck Taper Corrosion of Metal-On-Polyethylene Total Hip Arthroplasty

BackgroundThe accurate diagnosis of periprosthetic joint infection (PJI) in the setting of adverse local tissue reactions in patients with metal-on-polyethylene (MoP) total hip arthroplasty (THA) secondary to head-neck taper junction corrosion is challenging as it frequently has the appearance of purulence. The aim of this study is to evaluate the utility of erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and synovial fluid markers in diagnosing PJI in failed MoP THA due to head-neck taper corrosion.MethodsA total of 89 consecutive patients with MoP THA with head-neck taper corrosion in 2 groups was evaluated: (1) infection group (n = 11) and (2) noninfection group (n = 78). All patients had highly crossed polyethylene with cobalt chromium femoral heads and had preoperative synovial fluid aspiration. In addition, serum cobalt and chromium levels were analyzed.ResultsThe optimal cutoff value for synovial white blood cell was 2144 with 93% sensitivity and 84% specificity. Neutrophil count optimal cutoff value was 82% with 93% sensitivity and 82% specificity. Receiver operating characteristic analysis of ESR and CRP determined optimal cutoff at 57 mm/h and 35 mg/L with 57% sensitivity and 94% specificity and 93% sensitivity and 76% specificity, respectively. There were no significant differences in metal ion levels between the infected and noninfected groups.ConclusionThe results of this study suggest that ESR and CRP are useful in excluding PJI, whereas both synovial white blood cell count and neutrophil percentage in hip aspirate are useful markers for diagnosing infection in MoP THA patients with head-neck taper corrosion associated adverse local tissue reaction.     

What Are the Current Clinical Issues in Wear and Tribocorrosion?

Background

Wear and corrosion in joint arthroplasty are important causes of failure. From the standpoint of current clinical importance, there are four main categories of wear and tribocorrosion: polyethylene wear, ceramic-on-ceramic (CoC) bearing wear, metal-on-metal (MoM) bearing wear, and taper tribocorrosion. Recently, problems with wear in the knee have become less prominent as have many issues with hip polyethylene (PE) bearings resulting from the success of crosslinked PE. However, MoM articulations and taper tribocorrosion have been associated with soft tissue inflammatory responses, and as a result, they have become prominent clinical concerns.

Where Are We Now?

For PE wear in the hip, several advances include improved locking mechanisms and data supporting highly crosslinked polyethylenes (HXLPE). Edge-loading in CoC articulations can contribute to stripe wear and subsequent squeaking. For MoM articulations, the relationship of wear-to-edge loading, sensitivity to component positioning, typical soft tissue response, and use of imaging is increasingly understood. Taper tribocorrosion (from femoral head–neck junctions and other modular elements) and associated soft tissue inflammatory responses appear to be serious clinical issues that are not fully understood.

Where Do We Need to Go?

In the knee, clinical concerns remain with the efficacy of HXLPE, modular connections, and metal allergies. For PE wear in the hip, concerns remain regarding how to increase crosslinking of PE while minimizing PE fractures. With CoC articulations, questions remain on how to prevent noises, chipping, and impingement and if enhanced designs can contribute to improved results. For MoM articulations, we need to improve imaging tests for soft tissue reactions, determine best practices in terms of monitoring protocols, and better define if, how, and when to act on serum metal levels. For taper tribocorrosion, we need to use modularity wisely and also understand how to improve tapers and materials in the future. For patients at risk for tribocorrosion, we need to define realistic diagnostic and monitoring protocols. We also need to enhance revision methods, and the threshold of acceptable soft tissue damage, to minimize complications associated with soft tissue damage such as hip instability.

How Do We Get There?

HXLPE and other bearing surfaces will likely continue to be refined. We need to develop tapers with more resistance to tribocorrosion through improved understanding of the manufacturing process and ongoing engineering improvements. Revision procedures for wear and tribocorrosion can be enhanced by determining when partial component retention is appropriate and how best to manage soft tissue damage. For CoC articulations, enhanced designs are required to minimize noises, chipping, and impingement. Importantly, we must continue to promote and analyze joint replacement registries to identify early failures and analyze long-term successes.     

Fretting and Corrosion at the Backside of Modular Cobalt Chromium Acetabular Inserts: A Retrieval Analysis

Background

Adverse local tissue reaction formation has been suggested to occur with the Modular Dual Mobility (MDM) acetabular design. Few reports in the literature have evaluated fretting and corrosion damage between the acetabular shell and modular metal inserts in this modular system. We evaluated a series of 18 retrieved cobalt chromium MDM inserts for evidence of fretting and corrosion.

Trunnionosis: Is it really a problem?

Corrosion between the modular head and neck interface of uncemented femoral components was initially seen in retrieval studies of total hip implants in the mid- to late-1980s, but clinical symptoms related to these findings were relatively rare. Over the past 5–7 years, there has been a re-emergence of corrosion of the head–neck junction as an important symptomatic clinical entity and cause of revision of metal-on-polyethylene total hip arthroplasty. Trunnion or taper corrosion may be a multifactorial process, involving implant design, surgical technique, and patient characteristics. The clinical presentation of trunnion corrosion is variable and requires a high index of suspicion. Serum levels of cobalt and chromium ions and cross-sectional imaging are usually required to confirm the diagnosis. Treatment is revision surgery with femoral head exchange to a noncobalt–chromium alloy component. Complications after this procedure may be more frequent than expected.     

Is Ultrasound Screening Reliable for Adverse Local Tissue Reaction After Hip Arthroplasty?

There is increasing awareness of prevalence of adverse local tissue reaction (ALTR) surrounding metal-on-metal (MoM) and highly cross-linked polyethylene (HXLPE) bearings, and sensitive and simple screening modalities for ALTR are required. We examined reliability of ultrasound screening for ALTR in 131 hips of 105 patients who received both ultrasound and MRI examinations after hip arthroplasty with MoM or HXLPE bearings. Using the MRI results as reference, sensitivity, specificity and accuracy of ultrasound were 74%, 92% and 84% around MoM bearings, and 90%, 83%, and 85% around HXLPE bearings. Ultrasound detected ALTR in 11 hips that were not shown with MRI. Ultrasound examination is assumed to be a reliable screening tool for detecting clinically important ALTR lesions developing in the anterior region around MoM or HXLPE bearings.