Aseptic Lymphocytic Vasculitis-associated Lesions Research Articles

Semi-quantitative histology confirms that the macrophage is the predominant cell type in metal-on-metal hip tissues.

Numerous studies have examined the histology of metal‐on‐metal hip tissues for evidence of a dose response to metal wear but have often reported inconclusive or contradictory findings. The aim of the present study was to address these discrepancies using multiple histological scoring methods to characterize the tissue features of one large group of revised metal‐on‐metal total hips. Periprosthetic tissues from 165 metal‐on‐metal hip revisions were examined for features of aseptic lymphocytic vasculitis associated lesions (ALVAL) as rated using two scoring systems as well as rankings for macrophage and lymphocyte numbers, intracellular wear debris and necrosis. Correlations between histological features and clinical variables including gender and time to revision and implant variables including articular surface wear volume or visual taper corrosion scores were examined. Both ALVAL scores reflected the macrophage dominated histology with average scores of 5.9/10 and 1.5/3. There was a statistically significant correlation between the original ALVAL score and wear rate per year (correlation coefficient = 0.17, p = .05) and a moderate correlation between the number of macrophages and wear particles and wear volume. There was no statistically significant correlation between wear and any other feature including lymphocytic inflammation or necrosis. Strong correlations between combined cup and ball wear volume and histological characteristics were not observed, although the number of macrophages was more closely correlated with wear than lymphocytes or necrosis.

Clinicopathological and ALVAL score analysis of pseudotumor-like tissue around aseptic joint arthroplasty

Objective: To analyze the clinicopathological features of pseudotumor-like tissue around aseptic joint arthroplasty and aseptic lymphocytic vasculitis-associated lesions (ALVAL) scores. The characters of wear granules were observed. Methods: Total 122 cases were retrieved from the surgical pathology files between May 2015 and August 2018 in the department of pathology in Beijing Jishuitan Hospital, which included the knee joint arthroplasty (10 cases) and hip arthroplasty (112 cases). There were 62 females and 60 males. Patients' age ranged from 29 to 86 years (mean 56 years). The pseudotumor-like tissue around aseptic joint arthroplasty were stained with HE and analyzed by two ALVAL score systems. The characters of wear granules were observed by light microscope and polarized light. Results: The cohort included 62 females and 60 males. Patients' age ranged from 29 to 86 years (mean 56 years). Compbell-ALVAL system includes synovial lining,inflammatory infiltrate and tissue organization. The scores were: low (0-4): 18cases; moderate (5-8): 101 cases; high (9-10): 3 cases. Oxford-ALVAL system only evaluated the inflammatory infiltrate,and the scores were:0 grade:56 cases; 1 grade:51 cases; 2 grade: 12 cases; 3 grade:3 cases. Cases with high score in the Compbell-ALVAL system were concordant with the 3 grade of the Oxford-ALVAL system. Under light microscope,the metal particles were small black granules; the polyethylene fibers were needle-like and easily visible in polarized light. The polymethylmethacrylate showed clear spaces because of particle melting. Conclusions: The Compbell-ALVAL scoring system is based on the histologic analysis of pseudotumor-like tissue around aseptic joint arthroplasty, and the Oxford-ALVAL scoring systems is based on lymphocytic response. The wear particles could be differentiated by the features in the light microscope.

Five Hundred Fifty-five Retrieved Metal-on-metal Hip Replacements of a Single Design Show a Wide Range of Wear, Surface Features, and Histopathologic Reactions.

In 2010, a widely used metal-on-metal hip implant design was voluntarily recalled by the manufacturer because of higher than anticipated failure rates at 5 years. Although there was a large published range of revision rates, numerous studies had reported a higher risk of revision for excessive wear and associated adverse tissue reactions when compared with other metal-on-metal total hips. The reasons for this were suggested by some to be related to cup design features. From retrievals of ASR metal-on-metal implants and tissue samples obtained at revision surgery, we asked the following questions: (1) What were the common and uncommon surface features? (2) What were the common and uncommon linear and volumetric wear characteristics? (3) Were there common taper corrosion characteristics? (4) What aseptic lymphocytic vasculitis-associated lesion (ALVAL) features were present in the tissues? Five hundred fifty-five ASRs, including 23 resurfacings, were studied at one academic research center. Features of wear (eg, light and moderate scratching), damage (eg, deposits, gouges), and bone attachment on the porous coating were semiquantitatively ranked from 0 (none) to 3 (> 75%) based on the amount of a feature in each region of interest by the same experienced observer throughout the study. Visible features of head taper corrosion were ranked (Goldberg score) from 1 (none) to 4 (severe) by the same observer using a previously published scoring method. An experienced tribologist measured component wear depth using a coordinate measuring machine and quantified wear volume using previously validated methods. All available tissues were sampled and examined for features of ALVAL and scored from 0 to 10 by a single observer using a method they previously developed and published. A score from 0 to 4 is considered low, 5 to 8 is considered moderate, and 9 or 10 is considered high with regard to the risk of metal hypersensitivity features in the tissues. The most common bearing surface features were light and moderate scratches and removal or postremoval damage. Discoloration and deposits were commonly observed on femoral heads (55% [305 of 553]) and less commonly on cups (30% [165 of 546]). There was no evidence of impingement or dislocation damage. There was typically a small amount of bone attachment in at least one of eight designated regions of interest (84% [460 of 546]); extensive or no bone attachment was uncommon. Edge wear was highly prevalent. The maximum wear of 469 cups (88%) occurred near the edge, whereas the maximum wear of 508 femoral heads (94%) occurred between the pole and 45° from the pole. The median combined head-cup wear volume was 14 mm (range, 1-636 mm). One hundred sixty-nine pairs (32%) had a combined wear volume of < 10 mm, 42 pairs (8%) had volumetric wear of > 100 mm, and 319 pairs (60%) had wear volume between 10 and 100 mm³. Seventy-four percent of tapers (390 of 530) received a Goldberg score of 4, 22% (116 of 530) a score of 3, < 5% (24 of 530) a score of 2, and none received a score of 1. The most frequent ALVAL score was 5 out of 10 (35 of 144 hips [24%]) and ranged from 2 (one hip) to 10 (nine hips); 92 of 144 (64%) had a moderate score, 17 of 144 (12%) had a high score, and 35 (24%) had a low score. Although edge wear was prevalent, in most cases, this was not associated with high wear. The increased diameter and decreased coverage angle of the ASR design may have resulted in the observed high incidence of edge wear while perhaps decreasing the risk for impingement and dislocation. The role of bearing wear in the revisions of metal-on-metal implants is controversial, because it is known that there is a large range of in vivo wear rates even within the same implant type and that patient variability affects local tissue responses to wear debris. The observations from our study of 555 retrieved ASR implant sets indicate that there was a wide range of wear including a subset with very high wear. The results suggested that the failure of the ASR and ASR XL was multifactorial, and the failure of different subgroups such as those with low wear may be the result of mechanisms other than reaction to wear debris.

Adverse Local Tissue Reaction in Total Hip Replacement

&lt;p&gt;Total hip replacement (THR) utilizing metal-on-polyethylene articulations was successful for many years. Modifications in materials and implant designs were created to improve wear and allow greater ability to adjust the implant position, optimizing joint mechanics. Three recent cobalt-chromium designs that involve metal to metal contact (metal-on-metal or MoM, modular neck-stems, large metal femoral heads) have produced metal debris through corrosion, releasing cobalt ions around the implant. Unfortunately, these metal nanoparticles have led to a wide spectrum of soft tissue destruction called adverse local tissue reaction (ALTR). This review article assesses ALTR following THR using MoM cobalt-chromium designs, as well as the diagnostic testing used to identify at risk hips. Findings revealed that a possible explanation for ALTR is hypersensitivity to cobalt with lymphocytic perivascular infiltration, known as aseptic lymphocytic vasculitis associated lesion (ALVAL). Solid or cystic masses called “pseudotumors” may also form around the implant. Given the destructive nature of ALTR to the surrounding capsule, muscle, and bone, surgical revision of the MoM junction is generally required. In addition to physical examination and x-rays, diagnosis now depends on drawing serum cobalt and chromium levels, as well as the use of a metal artifact reduction suppression (MARS) MRI.&lt;/p&gt;&lt;p&gt;The authors believe that the optimal design and bearing surface for THR is a titanium femoral stem and acetabulum with a ceramic femoral head (32 or 36 mm) articulating on a polyethylene acetabular insert. Manufacturers have now produced a polyethylene with superior bearing characteristics, as evidenced by minimal wear after five to ten years of implantation. &lt;/p&gt;

CORR Insights(®): do patients with a failed metal-on-metal hip implant with a pseudotumor present differences in their peripheral blood lymphocyte subpopulations?

T he study by Catelas and colleagues adds to the current scientific consensus that adaptive immune responses to metals occurs in a subset of all people with metal implants. The study authors also found that the incidence of pseudotumors correlates with systemic evidence of metal-related delayed-type hypersensitivity (DTH) responses and elevated metal ion levels. The current study identifies alterations in circulating adaptive immune cells in people with elevated levels of metal debris and pseudotumors. These findings support past histological and T-cell function studies, indicating pseudotumors are more prevalent in people with DTH-type immune reactivity. This highlights the growing recognition of these phenomena as central to implant performance in some individuals/implant designs. Case and group studies [4, 5] indicate that once locally activated, adaptive immune inflammation to metal contributes to (if not, mediates) the pathogenesis of poor implant performance. Metal DTH reactivity is a lymphocyte mediated response, similar to a Type IV DTH reaction. Metal-on-metal (MoM) hip failures have been associated with classic DTH responses including periimplant activated lymphocyte accumulations (aseptic lymphocytic vasculitisassociated lesions, [ALVAL]), and dermal and functional lymphocyte hypersensitivity responses to metals [2, 7, 11]. Elevated metal exposure can also cause different forms of toxicity responses in tissue, bone, and immune cells, including cobalt-induced hypoxia-like responses, postulated as causing pseudotumors [10]. Lymphocyte reactivity (metal DTH responses/ALVAL) and pseudotumors can be caused separately [6, 8]. Currently, there are no accepted thresholds for systemic metal ion levels that necessarily indicate for pseudotumor formation or immune reactions [1, 7]; it remains an increased risk association. This CORR Insights is a commentary on the article ‘‘Do Patients With a Failed Metal-onmetal Hip Implant With a Pseudotumor Present Differences in Their Peripheral Blood Lymphocyte Subpopulations?’’ by Catelas and colleagues available at: DOI: 10.1007/ s11999-015-4466-8. The author certifies that she, or any members of her immediate family, has no funding or commercial associations (consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research editors and board members are on file with the publication and can be viewed on request. The opinions expressed are those of the writers and do not reflect the opinion or policy of CORR or The Association of Bone and Joint Surgeons. This CORR Insights comment refers to the article available at DOI: 10.1007/s11999015-4466-8. N. J. Hallab PhD (&) Department of Orthopedic Surgery, Rush University Medical Center, 1735 W Harrison, Cohn Research Bldg, #722, Chicago, IL 60612, USA e-mail: nhallab@rush.edu CORR Insights Published online: 13 October 2015 The Association of Bone and Joint Surgeons1 2015

Can wear explain the histological variation around metal-on-metal total hips?

There is a general perception that adverse local tissue reactions in metal-on-metal hip arthroplasties are caused by wear, but the degree to which this is the case remains controversial. To what extent is the magnitude of wear associated with (1) the histological changes; (2) presence of metallosis; and (3) likelihood of pseudotumor formation in the periprosthetic tissues? One hundred nineteen metal-on-metal total hip arthroplasties and hip resurfacings were selected from a retrieval collection of over 500 implants (collected between 2004 and 2012) based on the availability of periprosthetic tissues collected during revision, clinical data including presence or absence of pseudotumor or metallosis observed intraoperatively, and wear depth measured using a coordinate measurement machine. Histological features of tissues were scored for aseptic lymphocytic vasculitis-associated lesions (ALVAL). Correlation analysis was performed on the three endpoints of interest. With the sample size available, no association was found between wear magnitude and ALVAL score (ρ=-0.092, p=0.423). Median wear depth (ball and cup) was greater in hips with metallosis (137 μm; range, 8-873 μm) than in those without (18 μm; range, 8-174 μm; p<0.0001). With the numbers available, no statistically significant association between wear depth and pseudotumor formation could be identified; median wear depth was 74 μm in hips with pseudotumors and 26 μm in those without (p=0.741). Wear alone did not explain the histopathological changes in the periprosthetic tissues. A larger sample size and more sensitive outcome variable assessments may have revealed a correlation. However, wear depth has been inconsistently associated with pseudotumor formation, perhaps because some patients with hypersensitivity may develop pseudotumors despite low wear. Metal wear alone may not explain the histological reactions and pseudotumors around metal-on-metal hip implants.

Unusual Origin of Anemia With Gluteus Red Spots

A 62-year-old woman presented with a new history of dizziness, fatigue, scant red gluteal spots and microcytic anemia of 9.9 g/dL. One year and 8 months ago, she underwent total hip replacement with successful rehabilitation. On admission, pallor of skin and red spots of gluteus region on the operation side were seen (Fig. 1). Physical examination of internal organs was unremarkable. Both hip joint motions were within normal limits. Gastroand colonoscopy did not clarify any origin of anemia. Total body CT showed synovial mass around a hip prosthesis. MRI showed metal-on-metal hip joint transplant with moderate account of synovial fluid and extensive synovial mass distributed around the joint to trochanter pushing back gluteus maximus. Reactive lymphadenopathy was seen along to iliac and groin areas. Final needle biopsy of the periarticular mass was negative for acid fast, non-acid fast bacteria and malignancy and revealed extensive inflammation. All metal implants, and metal-on-metal in particular, corrode and cause a release of metal ions. Chromium, cobalt (N < 0.25 μg/L, patient 15 μg/L) and molybdenum were implicated in development of aseptic lymphocytic vasculitis associated lesions (ALVAL) [1]. The last was proposed as a hypothesis and as a reason of anemia and rash without prosthetic failure [2]. Next step was operative revision. Synovial mass was removed and showed typical lymphocytic vasculitis inflammatory tissue (Fig. 2) [3]. The metal-on-metal prosthesis was replaced to ceramic-to-ceramic device. Rapid recovery, disappearance of vasculitis and restoration of hemoglobin (12.3 g/dL) followed. Anemia was due to chronic inflammation and the metal mediated toxiciy.

MRI Predicts ALVAL and Tissue Damage in Metal-on-Metal Hip Arthroplasty

Adverse local tissue reactions (ALTR) around metal-on-metal (MOM) hip arthroplasties are increasingly being recognized as a cause of failure. These reactions may be associated with intraoperative tissue damage and complication rates as high as 50% after revision. Although MRI can identify ALTR in MOM hips, it is unclear whether the MRI findings predict those at revision surgery. We therefore (1) identified which MRI characteristics correlated with histologically confirmed ALTR (using the aseptic lymphocytic vasculitis-associated lesions [ALVAL] score) and intraoperative tissue damage and (2) developed a predictive model using modified MRI to detect ALVAL and quantify intraoperative tissue damage. We retrospectively reviewed 68 patients with failed MOM hip arthroplasties who underwent preoperative MRI and subsequent revision surgery. Images were analyzed to determine synovial volume, osteolysis, and synovial thickness. The ALVAL score was used to grade tissue samples, thus identifying a subset of patients with ALTR. Intraoperative tissue damage was graded using a four-point scale. Random forest analysis determined the sensitivity and specificity of MRI characteristics in detecting ALVAL (score ≥ 5) and intraoperative tissue damage. Maximal synovial thicknesses and synovial volumes as determined on MRI correlated with the ALVAL score and were higher in cases of severe intraoperative tissue damage. Our MRI predictive model showed sensitivity and specificity of 94% and 87%, respectively, for detecting ALVAL and 90% and 86%, respectively, for quantifying intraoperative tissue damage. MRI is sensitive and specific in detecting ALVAL and tissue damage in patients with MOM hip implants. MRI can be used as a screening tool to guide surgeons toward timely revision surgery.

MRI Findings in Painful Metal-on-Metal Hip Arthroplasty

The objective of our study was to compare the frequency of osseous and soft-tissue abnormalities in patients presenting with hip pain after resurfacing arthroplasty and after total hip arthroplasty (THA), correlate the MRI findings with histologic results, and determine which MRI findings are predictive of aseptic lymphocytic vasculitis-associated lesions. The MRI examinations of patients with metal-on-metal hip prostheses placed at resurfacing arthroplasty (n=31) or THA (n=29) were reviewed for osteolysis, synovitis, extracapsular disease, synovial pattern, and mode of decompression into adjacent bursae. Regional muscles and tendons were assessed for tendinosis, tear, atrophy, and edema. Histologic and operative findings were reviewed in 19 patients (20 hips) who underwent revision surgery. Chi-square tests were performed to detect differences between the resurfacing arthroplasty and THA groups. The Wilcoxon rank sum test was performed to detect differences in MRI findings in patients with and those without aseptic lymphocytic vasculitis-associated lesions. Synovitis was detected in 77.4% of resurfacing arthroplasty hips and 86.2% of THA hips. Extracapsular disease was present in 6.5% of resurfacing arthroplasty hips and 10.3% of THA hips. Osteolysis was detected in 9.7% of resurfacing arthroplasty hips and 24.1% of THA hips. There was no difference in the incidence of synovitis (p=0.51), osteolysis (p=0.17), or extracapsular disease (p=0.67) between the resurfacing arthroplasty and THA groups. Patients with aseptic lymphocytic vasculitis-associated lesions had higher volumes of synovitis (p=0.04) than patients without aseptic lymphocytic vasculitis-associated lesions. Extracapsular disease and muscle edema were seen only in patients with aseptic lymphocytic vasculitis-associated lesions. Synovitis is common in patients with metal-on-metal hip prostheses and occurs with a similar incidence after resurfacing arthroplasty and after THA; osteolysis and extracapsular disease are uncommon. The MRI signs most suggestive of aseptic lymphocytic vasculitis-associated lesions are high volumes of synovitis, extracapsular disease, and intramuscular edema.

MRI of Aseptic Lymphocytic Vasculitis–Associated Lesions in Metal-on-Metal Hip Replacements

The aim of this review is to describe the clinical, histopathologic, and MRI features of aseptic lymphocytic vasculitis-associated lesions in total hip replacements. The introduction of modern metal-on-metal hip arthroplasty has been accompanied by a newly described disease, aseptic lymphocytic vasculitis-associated lesions, which is characterized histologically by bland necrosis and dense perivascular lymphocytic infiltrates. Conventional radiographic findings are often normal, but the typical MRI findings include periprosthetic fluid collections, soft-tissue masses, gluteal tendon avulsion, bone loss, periosteal stripping, neurovascular involvement, and periprosthetic fractures. The severity of the histologic and MRI appearances can be graded according to defined published criteria.

Edge Loading Has a Paradoxical Effect on Wear in Metal-on-Polyethylene Total Hip Arthroplasties

Edge wear is an adverse factor that can negatively impact certain THAs. In some metal-on-metal THAs, it can lead to adverse tissue reactions including aseptic lymphocytic vasculitis-associated lesions and even to pseudotumor formation. In some ceramic-on-ceramic THAs, it can lead to squeaking and/or stripe wear. Edge wear in metal-on-metal and ceramic-on-ceramic THAs can also be associated with accelerated wear across the articulation of these joints. I asked: Does edge wear occur in metal-on-polyethylene (MOP) articulations? And if so, does it increase joint wear? I examined the evidence in the literature for edge wear occurring in MOP THA and then assessed the evidence in the literature for data supporting the concept that edge wear in MOP hips could accelerate wear across the articulation over time. Extensive data in the literature confirm edge wear is common in MOP THA. Surprisingly, the evidence does not support that it accelerates wear across the articulation. In fact, substantial data support the concept that it does not. These observations suggest, in terms of edge wear accelerating overall wear, MOP articulation may have a privileged position compared to hard-on-hard THA articulations.

Adverse reactions to metal debris: histopathological features of periprosthetic soft tissue reactions seen in association with failed metal on metal hip arthroplasties

AimTo describe the histopathology of localised adverse reactions to metal debris (ARMD) seen in association with failed metal on metal (MoM) hip arthroplasties. The nature of aseptic lymphocytic vasculitis associated...

Vorgehen bei schmerzhafter Kappenprothese

Hip resurfacing in young patients has been increasingly performed within the last decade. In comparison to standard total hip arthroplasty the failure rate remains high. Age and implant size have a significant effect on the risk of revision for primary total resurfacing and the risk of revision increases with increasing age. At 7 years the cumulative revision rate for patients is 5% and females have more than twice the cumulative revision rate as males. Even in hip resurfacing arthroplasty which has been performed in a perfect manner, a certain percentage of patients suffer from persistent pain for various reasons, such as neck fracture, iliopsoas tendinopathy, metal hypersensitivity, such as aseptic lymphocytic vasculitis associated lesions (ALVAL) and aseptic loosening. Diagnostic work-up of the painful hip resurfacing is challenging even for experienced surgeons. Recommendations for the diagnostic procedure are described.

Failure of a metal on metal hip prostheses presenting as a destructive soft tissue mass due to ALVAL

We would like to draw attention to the relatively new concept of ALVAL prosthetic failure, illustrated by the following clinical case. Whilst currently very topical and familiar to orthopaedic surgeons, it may not be as familiar to rheumatologists. A 58-year-old woman underwent a successful resurfacing procedure of the right hip in September 2003. She underwent a similar procedure for the left hip in April 2007. At the time of this surgery, a dislocation of the right prosthesis occurred which hampered recovery. She presented to A and E in April 2009 with difficulty weight bearing and painful movements of the right hip. She was apyrexial, had a WBC of 19.9 and a CRP of 96.3. A radiograph showed bilateral hip prostheses. On the right, there was thinning of the inferior femoral neck and a soft tissue mass was visible in the same region (Fig. 1). An ultrasound showed pannus around the right hip joint and a collection in the right psoas bursa. An aspirate revealed white cells and no organisms, with no growth on culture. A CT scan confirmed bony erosion at the inferior aspect of the femoral neck along with the soft tissue mass. The prosthesis was successfully revised to a total hip replacement, with a ceramic on ceramic bearing in May 2009. Significant amounts of stained and necrotic tissue were removed from around the original prosthesis. Histology showed fibrovascular connective tissue with extensive dystrophic calcification, chronic inflammatory infiltrate and hemosiderin-laden macrophages. Analysis of the removed prosthesis showed excessive wear of both the acetabular and the femoral components. She was diagnosed with Aseptic Lymphocytic-Vasculitis-Associated Lesion (ALVAL). The use of large metal on metal (MoM) bearings in hip replacement has been gaining in popularity. The superior wear characteristics, improved motion and stability have attractive benefits, especially in young active patients. The materials currently used are high carbon cobalt chromium alloys. Reports of problematic painful MoM hips associated with soft tissue masses have been increasing. They can be destructive and lead to infiltration and destruction of soft tissues, pain, dislocation, nerve irritation or palsy, or cause local bone resorption leading to component loosening or fracture [1]. Willerts et al. first reported patients undergoing revision for non-infected, painful MoM implants with histological findings of diffuse perivascular lymphocytic infiltrates with accumulation of macrophages and eosinophilic granulocytes with tissue necrosis and termed it ALVAL [2]. Later reports found similar histological findings [1, 3]. The underlying cellular reaction appears similar to a type IV hypersensitivity response [2], (sometimes referred to as metal hypersensitivity), though exact causation remains unclear [4]. The trigger appears to be an increased local concentration of metal ions, to which an excessive reaction is initiated in certain patients. Blood levels of metal ions are elevated with all MoM bearings [5]. The extent appears to be related to the orientation of the components [6–8], with the resulting abnormal biomechanics in malaligned prostheses leading to focal regions of increased wear. This is especially noticeable in women, where the smaller J. R. B. Hutt (&) 6 Nevis Road, Tooting, London SW17 7QX, UK e-mail: drhutt@hotmail.com

Grading the severity of soft tissue changes associated with metal-on-metal hip replacements: reliability of an MR grading system

Metal-on-metal (MoM) soft tissue reactions or aseptic lymphocytic vasculitis-associated lesions (ALVAL) are being recognised using metal artefact reduction (MAR) MR with increasing frequency following the advent of second generation metal-on-metal bearings, but there is no standardised technique for reporting of MR appearances in this disease. The aim of this study was to measure the reliability of a grading system designed for scoring the severity of MoM disease on MRI. MRI examinations of 73 hips in 59 patients were retrospectively selected and then anonymised, randomised and reviewed by three independent observers (musculoskeletal radiologists). Each MR examination was scored as either A: normal, B: infection, C1: mild MoM disease, C2: moderate MoM disease or C3: severe MoM disease according to pre-defined criteria. Kappa correlation statistics were used to compare the observations. There was substantial agreement among all three observers; the correlation coefficient between the two most experienced observers was κ = 0.78 [95% confidence intervals (CI): 0.68-0.88] and when compared with the least experienced observer coefficients were κ = 0.69 (95% CI: 0.57-0.80) and κ = 0.66 (95% CI: 0.54-0.78). The strongest correlation occurred for grades A, C2 and C3. The weakest correlations occurred for grades B and C1. The grading system described in this study is reliable for evaluating ALVAL in MoM prostheses using MR but is limited in differentiating mild disease from infection.

Histological Features of Pseudotumor-like Tissues From Metal-on-Metal Hips

BackgroundPseudotumor-like periprosthetic tissue reactions around metal-on-metal (M-M) hip replacements can cause pain and lead to revision surgery. The cause of these reactions is not well understood but could be due to excessive wear, or metal hypersensitivity or an as-yet unknown cause. The tissue features may help distinguish reactions to high wear from those with suspected metal hypersensitivity.Questions/purposesWe therefore examined the synovial lining integrity, inflammatory cell infiltrates, tissue organization, necrosis and metal wear particles of pseudotumor-like tissues from M-M hips revised for suspected high wear related and suspected metal hypersensitivity causes.MethodsTissue samples from 32 revised hip replacements with pseudotumor-like reactions were studied. A 10-point histological score was used to rank the degree of aseptic lymphocytic vasculitis-associated lesions (ALVAL) by examination of synovial lining integrity, inflammatory cell infiltrates, and tissue organization. Lymphocytes, macrophages, plasma cells, giant cells, necrosis and metal wear particles were semiquantitatively rated. Implant wear was measured with a coordinate measuring machine. The cases were divided into those suspected of having high wear and those suspected of having metal hypersensitivity based on clinical, radiographic and retrieval findings. The Mann-Whitney test was used to compare the histological features in these two groups.ResultsThe tissues from patients revised for suspected high wear had a lower ALVAL score, fewer lymphocytes, but more macrophages and metal particles than those tissues from hips revised for pain and suspected metal hypersensitivity. The highest ALVAL scores occurred in patients who were revised for pain and suspected metal hypersensitivity. Component wear was lower in that group.ConclusionsPseudotumor-like reactions can be caused by high wear, but may also occur around implants with low wear, likely because of a metal hypersensitivity reaction. Histologic features including synovial integrity, inflammatory cell infiltrates, tissue organization, and metal particles may help differentiate these causes.Clinical RelevancePainful hips with periprosthetic masses may be caused by high wear, but if this can be ruled out, metal hypersensitivity should be considered.

The Relationship between the Presence of Metallosis and Massive Infection in Metal-on-Metal Hip Replacements

With the increased use of metal-on-metal as a bearing surface, complications and side effects are being recognised more frequently. We present a small series of a previously unreported complication, which appears specific to metal-on-metal bearing surface arthroplasties: three cases of infection in the presence of local metal debris and histological features of aseptic lymphocytic vasculitis associated lesions (ALVAL). Each case is associated with significant soft tissue loss and bone destruction to such an extent that pelvic discontinuity has occurred. We postulate that the combination of metal debris, ALVAL and tissue necrosis provides a unique environment for peri-prosthetic bacterial growth and rapid spread of infection.

No Superiority of Cemented Metal-on-Metal Over Metal-on-Polyethylene THA in a Randomized Controlled Trial at 10-Year Follow-up

In a randomized controlled trial, 102 cemented Stanmore 28-mm metal-on-metal total hip arthroplasties (THAs) were compared to 98 metal-on-polyethylene THAs in 195 patients. At a mean follow-up of 10 years, 11 patients (11 hips) were lost to follow-up, 53 patients (55 hips) died, and 6 patients (6 hips) underwent revision. Average age of the surviving patients was 79 years. Harris Hip Scores and Oxford Hip Scores had increased significantly in both groups (P=.000). Ten years postoperatively, mean Harris Hip Score was 86 in the metal-on-metal patients and 87 in the metal-on-polyethylene patients (P=.441); Oxford Hip Scores were 27 and 24, respectively (P=.494). Wear was present in 30 of 52 polyethylene cups. Periprosthetic radiolucencies were seen in 57% of the metal-on-metal patients and in 52% of the metal-on-polyethylene patients (P=.680); they were mainly seen in DeLee & Charnley's zones 1 and 2. Serum cobalt and chromium concentration were higher in the metal-on-metal group (cobalt 1.1, chromium 1.0 vs 0.5 and 0.5 mug/L, respectively; P<.001). Patients with high ion levels (maximum 9.5 and 11 mug/L, respectively) all showed high Harris Hip Scores and few or no periprosthetic radiolucencies, and none were revised. Ten-year survival was 95.5% in the metal-on-metal group (4 revisions) and 96.8% in the metal-on-polyethylene group (2 revisions; P=.402). All revisions were indicated for aseptic loosening. One case of aseptic lymphocytic vasculitis-associated lesions and no pseudotumors were observed. The absence of clinical superiority of the cemented metal-on-metal bearing and the concerns over their biological effects have led us to favor the cemented metal-on-polyethylene THA.

Hip resurfacing: expectations and limitations

Hip resurfacing: expectations and limitations