This study aims to assess the relationship between history of pseudotumour formation secondary to metal-on-metal (MoM) implants and periprosthetic joint infection (PJI) rate, as well as establish ESR and CRP thresholds that are suggestive of infection in these patients. We hypothesized that patients with a pseudotumour were at increased risk of infection. A total of 1,171 total hip arthroplasty (THA) patients with MoM articulations from August 2000 to March 2014 were retrospectively identified. Of those, 328 patients underwent metal artefact reduction sequence MRI and had minimum two years’ clinical follow-up, and met our inclusion criteria. Data collected included demographic details, surgical indication, laterality, implants used, history of pseudotumour, and their corresponding preoperative ESR (mm/hr) and CRP (mg/dl) levels. Multivariate logistic regression modelling was used to evaluate PJI and history of pseudotumour, and receiver operating characteristic curves were created to assess the diagnostic capabilities of ESR and CRP to determine the presence of infection in patients undergoing revision surgery.Aims
Methods
Hip resurfacing may be a useful surgical procedure when patient selection is correct and only implants with superior performance are used. In order to establish a body of evidence in relation to hip resurfacing, pseudotumour formation and its genetic predisposition, we performed a case-control study investigating the role of HLA genotype in the development of pseudotumour around MoM hip resurfacings. All metal-on-metal (MoM) hip resurfacings performed in the history of the institution were assessed. A total of 392 hip resurfacings were performed by 12 surgeons between February 1st 2005 and October 31st 2007. In all cases, pseudotumour was confirmed in the preoperative setting on Metal Artefact Reduction Sequencing (MARS) MRI. Controls were matched by implant (ASR or BHR) and absence of pseudotumour was confirmed on MRI. Blood samples from all cases and controls underwent genetic analysis using Next Generation Sequencing (NGS) assessing for the following alleles of 11 HLA loci (A, B, C, DRB1, DRB3/4/5, DQA1, DQB1, DPB1, DPA1). Statistical significance was determined using a Fisher's exact test or Chi-Squared test given the small sample size to quantify the clinical association between HLA genotype and the need for revision surgery due to pseudotumour. Both groups were matched for implant type (55% ASR, 45% BHR in both the case and control groups). According to the ALVAL histological classification described by Kurmis et al., the majority of cases (63%, n=10) were found to have group 2 histological findings. Four cases (25%) had group 3 histological findings and 2 (12%) patients had group 4 findings. Of the 11 HLA loci analysed, 2 were significantly associated with a higher risk of pseudotumour formation (DQB1*05:03:01 and DRB1*14:54:01) and 4 were noted to be protective against pseudotumour formation (DQA1*03:01:01, DRB1*04:04:01, C*01:02:01, B*27:05:02). These findings further develop the knowledge base around specific HLA genotypes and their role in the development of pseudotumour formation in MoM hip resurfacing. Specifically, the two alleles at higher risk of pseudotumour formation (DQB1*05:03:01 and DRB1*14:54:01) in MoM hip resurfacing should be noted, particularly as patient-specific genotype-dependent surgical treatments continue to develop in the future.
Head-taper corrosion is a cause of failure in total hip arthroplasty (THA). Recent reports have described an increasing number of V40 taper failures with adverse local tissue reaction (ALTR). However, the real incidence of V40 taper damage and its cause remain unknown. The aim of this study was to evaluate the long-term incidence of ALTR in a consecutive series of THAs using a V40 taper and identify potentially related factors. Between January 2006 and June 2007, a total of 121 patients underwent THA using either an uncemented (Accolade I, made of Ti12Mo6Zr2Fe; Stryker, USA) or a cemented (ABG II, made of cobalt-chrome-molybdenum (CoCrMo); Stryker) femoral component, both with a V40 taper (Stryker). Uncemented acetabular components (Trident; Stryker) with crosslinked polyethylene liners and CoCr femoral heads of 36 mm diameter were used in all patients. At a mean folllow-up of 10.8 years (SD 1.1), 94 patients (79%) were eligible for follow-up (six patients had already undergone a revision, 15 had died, and six were lost to follow-up). A total of 85 THAs in 80 patients (mean age 61 years (24 to 75); 47 (56%) were female) underwent clinical and radiological evaluation, including the measurement of whole blood levels of cobalt and chrome. Metal artifact reduction sequence MRI scans of the hip were performed in 71 patients.Aims
Methods
This study compared the cobalt and chromium serum ion concentration of patients treated with two different metal-on-metal (MoM) hinged total knee arthroplasty (TKA) systems, as well as a titanium nitride (TiN)-coated variant. A total of 63 patients (65 implants) were treated using either a MoM-coated (n = 29) or TiN-coated (n = 7) hinged TKA (GenuX mobile bearing, MUTARS; Implantcast, Germany) versus the BPKS (Brehm, Germany) hinged TKA (n = 27), in which the weight placed on the MoM hinge is diffused through a polyethylene (PE) inlay, reducing the direct load on the MoM hinge. Serum cobalt and chromium ion concentrations were assessed after minimum follow-up of 12 months, as well as functional outcome and quality of life.Aims
Methods
Large-diameter metal-on-metal (MoM) total hip arthroplasty (THA) has demonstrated unexpected high failure rates and pseudotumour formation. The purpose of this prospective cohort study is to report ten-year results in order to establish revision rate, prevalence of pseudotumour formation, and relation with whole blood cobalt levels. All patients were recalled according to the guidelines of the Dutch Orthopaedic Association. They underwent clinical and radiographical assessments (radiograph and CT scan) of the hip prosthesis and whole blood cobalt ion measurements. Overall, 94 patients (95 hips) fulfilled our requirements for a minimum ten-year follow-up.Aims
Methods
The present study investigated the five-year interval changes in pseudotumours and measured serum metal ions at long-term follow-up of a previous report of 28 mm diameter metal-on-metal (MoM) total hip arthroplasty (THA). A total of 72 patients (mean age 46.6 years (37 to 55); 43 men, 29 women; 91 hips) who underwent cementless primary MoM THA with a 28 mm modular head were included. The mean follow-up duration was 20.3 years (18 to 24). All patients had CT scans at a mean 15.1 years (13 to 19) after the index operation and subsequent follow-up at a mean of 20.2 years (18 to 24). Pseudotumour volume, type of mass, and new-onset pseudotumours were evaluated using CT scanning. Clinical outcomes were assessed by Harris Hip Score (HHS) and the presence of groin pain. Serum metal ion (cobalt (Co) and chromium (Cr)) levels were measured at the latest follow-up.Aims
Patients and Methods
Pseudotumor or high grade ALVAL (aseptic lymphocyte-dominated vasculitis-associated lesion) development around total hip replacements secondary to local metal debris generation – especially in the setting of metal-on-metal bearings – is a well-recognised histopathologic phenomenon. Recent work has suggested a strong genetic correlation with an individual's risk of such lesion development following metal exposure. Emerging data have highlighted a similar potential concern around total knee replacements (TKRs), particularly with increasing construct modularity. To date, the body-of-knowledge pertaining to TKR-associated ALVALs has largely been limited to individual case reports or small retrospective case series’, with no large-scale investigation looking at this potential complication. This study sought to establish the preliminary prevalence of pseudotumor or high grade ALVAL formation seen at the revision of primary TKRs and to establish the correlation between histologic ALVAL grade and patient-reported functional outcomes. Findings of 1263 consecutive patients undergoing revision knee surgery, at a high-volume referral center, were reviewed. 161 cases of active infection were excluded. Complete histopathology reports were subsequently available for 321 (29.1%) non-infective cases. Each case was independently histologically-classified using a previously validated scoring system reflecting ALVAL grade. Post-operative patient-reported outcomes measures (PROMs) were available for 134 patients (41.7%), allowing direct correlation between functional performance and the established histopathology results.Background
Methods
Our primary purpose was to study the rate of occurrence and the natural course of pseudotumors in patients who had not required a revision procedure. Our secondary purpose was to see if there is a relationship between serum metal ion analysis and clinical symptoms with metal-on-metal (MOM) hip arthroplasty. We used repeated metal artifact reduction sequence (MARS) magnetic resonance imaging (MRI) to screen 17 unrevised hips (mean patient age 63.0 years, 43 to 83 years) with pseudotumors and 26 hips (mean patient age 63.2 years, 47 to 83 years) without pseudotumors. Patients with 17 MOM, 17 ceramic-on-polyethylene (COP) and 7 ceramic on ceramic (COC) who had undergone repeated MARS MRI were evaluated with or without any symptoms. We utilized MARS MRI to score the type of pseudotumors using the Hart method. The mean post-operative time to the first MARS MRI scan was 30.0 months (8 to 96), and the time between the first and the second MARS MRI scan was eleven months (6 to 12). Serum Cr and Co ion measurements were undertaken at the time of both MRIs and analyzed only after MOM total hip arthroplasty.Purpose
Patients and Methods
The leading indication for revision total hip
arthroplasty (THA) remains aseptic loosening owing to wear. The younger,
more active patients currently undergoing THA present unprecedented
demands on the bearings. Ceramic-on-ceramic (CoC) bearings have
consistently shown the lowest rates of wear. The recent advances,
especially involving alumina/zirconia composite ceramic, have led
to substantial improvements and good results Alumina/zirconia composite ceramics are extremely hard, scratch
resistant and biocompatible. They offer a low co-efficient of friction
and superior lubrication and lower rates of wear compared with other
bearings. The major disadvantage is the risk of fracture of the
ceramic. The new composite ceramic has reduced the risk of fracture
of the femoral head to 0.002%. The risk of fracture of the liner
is slightly higher (0.02%). Assuming that the components are introduced without impingement,
CoC bearings have major advantages over other bearings. Owing to
the superior hardness, they produce less third body wear and are
less vulnerable to intra-operative damage. The improved tribology means that CoC bearings are an excellent
choice for young, active patients requiring THA. Cite this article:
Pseudotumors have been reported following metal-on-metal total hip arthroplasty (THA); however, the natural history and longitudinal imaging findings of pseudotumors have yet to be fully analyzed. Our hypothesis was that pseudotumor size might change over time following metal-on-metal THA. This hypothesis was studied longitudinally using magnetic resonance imaging (MRI). Screening for pseudotumors was performed using MRI after large-diameter metal-on-metal THA. Initial MRI was conducted at a mean of 36 months postoperatively. Follow-up MRI was performed at a mean of 20 months after the detection of 24 pseudotumors in 20 asymptomatic patients. Pseudotumors were classified as cystic, solid, and mixed types. Fourteen hips were characterized as cystic type and 10 hips were defined as mixed type. There were three men and 17 women with a mean age of 63 years. Pseudotumor size was determined on MRI by manually outlining the greatest size of the mass. Serum cobalt and chromium ion levels were measured in nine patients with unilateral THA at the time of MRI. Statistical analysis was performed using the Kruskal-Wallis test and chi square test to compare age, gender, BMI, head diameter, cup inclination, cup anteversion, and pseudotumor type among changes of pseudotumor size. We compared the pseudotumor size for the three groups (increase in size, no change, decrease in size) using Kruskal-Wallis test and Mann-Whitney U test. Wilcoxon signed-rank test was used to compare median serum metal ion levels over time. A p value < 0.05 was considered significant. This study was approved by the ethics committee of our institution, and all patients provided informed consent.Introduction
Materials and Methods
Between April 2008 and February 2012, we implanted 159 large-diameter MOM stemmed THA with head diameters of 38–50mm. There were 6–38mm, 22–40mm, 42–42mm, 42–44mm, 24–46mm, 13–48mm, 4–50mm, 5–52mm, and one-54mm heads implanted in 138 patients (21 males and 117 females). The pre-operative diagnoses included: 120 OAs, 12 IONs, 4 femoral neck fractures, one RA, and one post-traumatic OA. Their ages were 40–86 years (avg. 63.6 yrs). Follow up was 4 to 67 months post implantation (avg. 40.4 months). All implants were manufactured by one company (Wright Medical Technology, Arlington, TN, USA). The stems were of a standard titanium-aluminum alloy, either 44 ANCA-FIT or 115 PROFEMUR Z non-cemented stems. Acetabular components were all CONSERVE PLUS cobalt-chromium monoblock shells. Heads were also fabricated out of cobalt-chromium alloy, with modular junctions. Patients with complaints of groin pain and/or swelling or hip instability underwent MRI examination in order to detect the presence of fluid collections or soft tissue masses. The statistical correlation between abnormal findings on MRI and age, gender, head diameter, component position and duration post-surgery was performed. 35 hips in 31 patients (22.0%) were found to have either a fluid collection or “pseudotumor” on MRI. These were in 5 males and 26 female patients. According to Hart's MRI classification, they were classified 21 hips in Type 1, twelve hips in Type 2, and two hips in Type 3 (Fig. 1, 2 and 3). 8 hips in 8 patients who had any pseudotumors were undergone revision THA (Fig. 4, 5 and 6). All hips had corrosions at head-neck taper junctions (Fig. 7). There was no difference in age between these two groups of patients (63.7 vs. 63.6 yrs.), but a significant difference in duration from the time of implantation of two groups (23.9 vs. 44.8 months). There appeared to be no significant difference between the mean head diameter of the two groups, 43.2mm and 44.0mm respectively. There was no statistical difference between the two groups with regard to implant orientation: cup inclination 18–70 degrees (41.8 vs. 43.6 degrees); cup anteversion −13–49 degrees (15.1 vs. 14.7 degrees); stem anteversion 2–48 degrees (20.1 vs. 23.3 degrees); and stem offset 17.5–56.2mm (38.2 vs. 37.8mm). Furthermore, according to Lewinnek's safe zone, there was no difference in cup orientation between the two groups (Fig. 8). When we investigated the types of modular neck, the hips having any pesudotumors tended to have long or varus necks. In this study, it is important to emphasize that the appearance of symptoms and development of a pseudotumor occurred early after a MOM THA in some patients. Also it will be important to subject all patients to MRI examination to evaluate the possibility of “silent” fluid collections and pseudotumors. In large-diameter head metal-on-metal stemmed THAs, femoral stems having long or varus neck may contribute to head-neck junction failure.
We investigated the changes seen on serial metal
artefact reduction magnetic resonance imaging scans (MARS-MRI) of
metal-on-metal total hip arthroplasties (MoM THAs). In total 155
THAs, in 35 male and 100 female patients (mean age 70.4 years, 42
to 91), underwent at least two MRI scans at a mean interval of 14.6
months (2.6 to 57.1), at a mean of 48.2 months (3.5 to 93.3) after
primary hip surgery. Scans were graded using a modification of the
Oxford classification. Progression of disease was defined as an
increase in grade or a minimum 10% increase in fluid lesion volume
at second scan. A total of 16 hips (30%) initially classified as
‘normal’ developed an abnormality on the second scan. Of those with
‘isolated trochanteric fluid’ 9 (47%) underwent disease progression,
as did 7 (58%) of ‘effusions’. A total of 54 (77%) of hips initially
classified as showing adverse reactions to metal debris (ARMD) progressed,
with higher rates of progression in higher grades. Disease progression
was associated with high blood cobalt levels or an irregular pseudocapsule
lining at the initial scan. There was no association with changes
in functional scores. Adverse reactions to metal debris in MoM THAs
may not be as benign as previous reports have suggested. Close radiological
follow-up is recommended, particularly in high-risk groups. Cite this article:
We conducted a retrospective study to assess
the prevalence of adverse reactions to metal debris (ARMD) in patients
operated on at our institution with metal-on-metal (MoM) total hip
replacements with 36 mm heads using a Pinnacle acetabular shell.
A total of 326 patients (150 males, 175 hips; 176 females, 203 hips)
with a mean age of 62.7 years (28 to 85) and mean follow-up of 7.5
years (0.1 to 10.8) participating in our in-depth modern MoM follow-up
programme were included in the study, which involved recording whole
blood cobalt and chromium ion measurements, Oxford hip scores (OHS)
and plain radiographs of the hip and targeted cross-sectional imaging. Elevated
blood metal ion levels (>
5 parts per billion) were seen in 32 (16.1%)
of the 199 patients who underwent unilateral replacement. At 23
months after the start of our modern MoM follow-up programme, 29
new cases of ARMD had been revealed. Hence, the nine-year survival
of this cohort declined from 96% (95% CI 95 to 98) with the old
surveillance routine to 86% (95% CI 82 to 90) following the new
protocol. Although ARMD may not be as common in 36 mm MoM THRs as
in those with larger heads, these results support the Medicines
and Healthcare Products Regulatory Agency guidelines on regular
reviews and further investigations, and emphasise the need for specific
a follow-up programme for patients with MoM THRs. Cite this article:
The August 2014 Hip &
Pelvis Roundup360 looks at: Serial MRIs best for pseudotumour surveillance; Is ultrasound good enough for MOM follow-up?; Does weight loss in obese patients help?; Measuring acetabular anteversion on plain films; Two-stage one-stage too many in fungal hip revisions? and 35 is the magic number in arthroplasty.
The February 2014 Hip &
Pelvis Roundup360 looks at: length of stay; cementless metaphyseal fixation; mortality trends in over 400,000 total hip replacements; antibiotics in hip fracture surgery; blood supply to the femoral head after dislocation; resurfacing and THR in metal-on-metal replacement; diabetes and hip replacement; bone remodelling over two decades following hip replacement; and whether bisphosphonates affect acetabular fixation.
The aim of this study was to establish the natural
course of unrevised asymptomatic pseudotumours after metal-on-metal
(MoM) hip resurfacing during a six- to 12-month follow-up period.
We used repeated metal artefact reduction sequence (MARS)-magnetic
resonance imaging (MRI), serum metal ion analysis and clinical examination to
study 14 unrevised hips (mean patient age 52.7 years, 46 to 68,
5 female, 7 male) with a pseudotumour and 23 hips (mean patient
age 52.8 years, 38 to 69, 7 female, 16 male) without a pseudotumour.
The mean post-operative time to the first MARS-MRI scan was 4.3 years
(2.2 to 8.3), and mean time between the first and second MARS-MRI scan
was eight months (6 to 12). At the second MRI scan, the grade of
severity of the pseudotumour had not changed in 35 hips. One new
pseudotumour (Anderson C2 score, moderate) was observed, and one
pseudotumour was downgraded from C2 (moderate) to C1 (mild). In
general, the characteristics of the pseudotumours hardly changed. Repeated MARS-MRI scans within one year in patients with asymptomatic
pseudotumours after MoM hip resurfacing showed little or no variation.
In 23 patients without pseudotumour, one new asymptomatic pseudotumour
was detected. This is the first longitudinal study on the natural history of
pseudotumours using MARS-MRI scans in hip resurfacing, and mirrors
recent results for 28 mm diameter MoM total hip replacement. Cite this article:
Pseudotumour formation is being reported with increasing frequency in failing metal-on-metal hip resurfacings and replacements. This mode of failure complication has also been reported with metal-on-polyethylene bearing bearings when it is usually associated with evidence of surface corrosion and no apparent wear at the head–neck taper. We present a case with evidence of taper wear and damage secondary to corrosion in an uncemented total hip replacement with a metal on polyethylene articulation (TMZF (Titanium, Molybdenum, Zirconium and Ferrous) Accolade® stem, Trident® HA coated acetabular shell, Low Friction Ion Treatment (LFIT™) Cobalt-Chrome anatomic head (40 mm), X3® polyethylene liner) A 69 year old woman had a THR in 2008. A year later she started to complain of lateral based hip pain. Clinical examination and initial imaging indicated trochanteric bursitis and heterotopic bone formation. The symptoms became worse over the next 3 years and the patient was listed for exploration and excision of heterotopic bone. Extensive pseudotumour was encountered deep to bursa and adherent to capsule. Abductors, external rotators and vastus lateralis were spared. There was minimal calcar osteolysis and marginal erosion in superior acetabulum. There was no obvious wear on the articulating surfaces of the femoral head and polyethylene inlay of the socket nor was there any evidence of neck-to-rim impingement or edge loading. There was visible blackening of both the taper and trunnion after femoral head removal.Case
Surgical findings
Background.
