Metal particles detached from metal-on-metal hip prostheses (MoM-THA) have been shown to cause inflammation and destruction of tissues. To further explore this, we investigated the histopathology (aseptic lymphocyte-dominated vasculitis-associated lesions (ALVAL) score) and metal concentrations of the periprosthetic tissues obtained from patients who underwent revision knee arthroplasty. We also aimed to investigate whether accumulated metal debris was associated with ALVAL-type reactions in the synovium. Periprosthetic metal concentrations in the synovia and histopathological samples were analyzed from 230 patients from our institution from October 2016 to December 2019. An ordinal regression model was calculated to investigate the effect of the accumulated metals on the histopathological reaction of the synovia.Aims
Methods
Previous publications have suggested that the incidence of revisions due to infection after THA is increasing. We performed updated time-trend analyses of risk and timing of revision due to infection after primary THAs in the Nordic countries during the period 2004–2018. 569,463 primary THAs reported to the Nordic Arthroplasty Register Association from 2004 through 2018 were studied. We estimated adjusted hazard ratios (aHR) with 95% confidence interval by Cox regression with the first revision due to infection after primary THA as endpoint. The risk of revision was investigated. In addition, we explored changes in the time span from primary THA to revision due to infection.Aim
Methods
Young patients are at increased risk of revision after primary THA (THA). The bearing surface may be of importance for the longevity of the joint. We aimed to compare the risk of revision of primary stemmed cementless THA with MoM and CoC with metal-on-highly-crosslinked-polyethylene (MoXLP) bearings in patients between 20–54 years. From NARA, we included 2,153 MoM, 4,120 CoC and 10,329 MoXLP THA operated between 1995 and 2017. Kaplan-Meier estimator was used for calculation of THA survivorship and Cox regression to estimate the hazard ratio (HR) of revision (95% CI) due to any and specific causes. MoXLP was reference. The median follow-up was 10.3 years for MoM, 6.6 years for CoC and 4.8 years for MoXLP. 15 years postoperatively the Kaplan-Meier survival estimates were 80% (78–83%) for MoM, 92% (91–93%) for CoC and 94% (93–95%) for MoXLP. The 0–2, 2–7 and 7–15 years adjusted HRs of revision by any cause were 1.4 (0.9–2.4), 3.2 (2.1–5.1) and 3.9 (1.9–7.9) for MoM and 1.1 (0.8–1.4), 1.0 (0.7–1.3) and 2.5 (1.3–4.8) for CoC bearings. After 7–15 years follow-up, the unadjusted HR of revision due to aseptic loosening was 5.4 (1.2–24) for MoM and 4.2 (0.9–20) for CoC THA. MoM and CoC had a 7–15 year adjusted HR of revision due to ‘other’ causes of 4.8 (1.6–14) and 2.1 (0.8–5.8). MoXLP bearings were associated with better survival than MoM and CoC bearings, mainly because of lower risk of revision due to aseptic loosening and ‘other’ causes.
The main advantage of 3D-printed, off-the-shelf acetabular implants is the potential to promote enhanced bony fixation due to their controllable porous structure. In this study we investigated the extent of osseointegration in retrieved 3D-printed acetabular implants. We compared two groups, one made via 3D-printing (n = 7) and the other using conventional techniques (n = 7). We collected implant details, type of surgery and removal technique, patient demographics, and clinical history. Bone integration was assessed by macroscopic visual analysis, followed by sectioning to allow undecalcified histology on eight sections (~200 µm) for each implant. The outcome measures considered were area of bone attachment (%), extent of bone ingrowth (%), bone-implant contact (%), and depth of ingrowth (%), and these were quantified using a line-intercept method.Aims
Methods
To find out if there is an inverse association between estimated glomerular filtration rate (eGFR) and whole blood cobalt (Co) and chromium (Cr) levels in patients with metal-on-metal (MoM) hip arthroplasties and renal insufficiency, suggesting that renal insufficiency could cause accumulation of Co and Cr in blood. Out of 2,520 patients with 3,013 MoM hip arthroplasties, we identified 1,244 patients with whole blood Co, Cr, and creatinine measured within no more than a one-year interval. We analyzed the correlation of blood metal ion levels and eGFR to identify a potential trend of accumulating Co or Cr with decreasing eGFR.Aims
Methods
To investigate whether chronic kidney disease (CKD) is associated with the risk of all-cause revision or revision due to a periprosthetic joint infection (PJI) after primary hip or knee arthroplasty. This retrospective cohort study comprised 18,979 consecutive hip and knee arthroplasties from a single high-volume academic hospital. At a median of 5.6 years (interquartile range (IQR) 3.5 to 8.1), all deaths and revisions were counted. To overcome the competing risk of death, competing risk analysis using the cumulative incidence function (CIF) was applied to analyze the association between different stages of CKD and revisions. Confounding factors such as diabetes and BMI were considered using either a stratified CIF or the Fine and Gray model.Aims
Methods
The optimum clearance between the bearing surfaces of hip arthroplasties is unknown. Theoretically, to minimize wear, it is understood that clearances must be low enough to maintain optimal contact pressure and fluid film lubrication, while being large enough to allow lubricant recovery and reduce contact patch size. This study aimed to identify the relationship between diametrical clearance and volumetric wear, through the analysis of retrieved components. A total of 81 metal-on-metal Pinnacle hips paired with 12/14 stems were included in this study. Geometrical analysis was performed on each component, using coordinate and roundness measuring machines. The relationship between their as-manufactured diametrical clearance and volumetric wear was investigated. The Mann-Whitney U test and unpaired Aims
Methods
The risk for developing a periprosthetic joint infection (PJI) as a consequence of bacteremia is not clear, except for All patients with a primary knee or hip joint replacement performed between September 2002 and December 2013 in a tertiary care hospital (n=14 378) were retrospectively followed up until December 2014. The mean follow-up time was 6.0 years (range 0–12 years). Positive blood culture results of the patients during the study period were obtained. PJIs during the study period were identified from several data sources. PJIs as a consequence of bacteremia were recorded and confirmed from patient records. Primary PJIs resulting in bacteremia were excluded. Binary logistic regression with univariate analysis was used to study potential risk factors for PJI among those with bacteremia.Aim
Method
The Attune total knee arthroplasty (TKA) has been used in over 600 000 patients worldwide. Registry data show good clinical outcome; however, concerns over the cement-tibial interface have been reported. We used retrieval analysis to give further insight into this controversial topic. We examined 12 titanium (Ti) PFC Sigma implants, eight cobalt-chromium (CoCr) PFC Sigma implants, eight cobalt-chromium PFC Sigma rotating platform (RP) implants, and 11 Attune implants. We used a peer-reviewed digital imaging method to quantify the amount of cement attached to the backside of each tibial tray. We then measured: 1) the size of tibial tray thickness, tray projections, peripheral lips, and undercuts; and 2) surface roughness (Ra) on the backside and keel of the trays. Statistical analyses were performed to investigate differences between the two designs.Objectives
Methods
Previous studies have suggested that metal-on-metal (MoM) Pinnacle (DePuy Synthes, Warsaw, Indiana) hip arthroplasties implanted after 2006 exhibit higher failure rates. This was attributed to the production of implants with reduced diametrical clearances between their bearing surfaces, which, it was speculated, were outside manufacturing tolerances. This study aimed to better understand the performance of Pinnacle Systems manufactured before and after this event. A total of 92 retrieved MoM Pinnacle hips were analyzed, of which 45 were implanted before 2007, and 47 from 2007 onwards. The ‘pre-2007’ group contained 45 implants retrieved from 21 male and 24 female patients, with a median age of 61.3 years (interquartile range (IQR) 57.1 to 65.5); the ‘2007 onwards’ group contained 47 implants retrieved from 19 male and 28 female patients, with a median age of 61.8 years (IQR 58.5 to 67.8). The volume of material lost from their bearing and taper surfaces was measured using coordinate and roundness measuring machines. These outcomes were then compared statistically using linear regression models, adjusting for potentially confounding factors.Objectives
Methods
Numerous studies have reported on clinically significant volumes of material loss and corrosion at the head-stem junction of metal-on-metal (MOM) hips; less is understood about metal-on-polyethylene (MOP) hips. We compared the effect of bearing type (MOM vs MOP) on taper material loss for a hip system of a single design (DePuy Pinnacle). We recruited retrieved MOM (n=30) and MOP (n=22) bearing hips that were consecutively received at our centre. We prospectively collected associated clinical and imaging data. We measured the severity of corrosion and volumes of material loss at each head taper surface and used multivariate statistical analysis to investigate differences between the two bearing types.Introduction
Methods
To determine whether there is any association between glomerular
filtration rate (GFR) and blood cobalt (Co) and chromium (Cr) levels
in patients with metal-on-metal (MoM) hip arthroplasty. We identified 179 patients with a unilateral 36 mm diameter head
as part of a stemmed Summit-Pinnacle MoM hip arthroplasty. GFR was
calculated using the Modification of Diet in Renal Disease formula.Aims
Patients and Methods
Recent studies have demonstrated that implant-specific blood metal ion thresholds exist in unilateral and bilateral metal-on-metal (MoM) hip arthroplasty patients, with these thresholds being most effective for identifying patients at low-risk of adverse reactions to metal debris (ARMD). We investigated whether these new blood metal ion thresholds could effectively identify patients at risk of ARMD in an external cohort of MoM hip arthroplasty patients. We performed a validation study involving 803 MoM hip arthroplasties implanted in 710 patients at three European centres (323=unilateral Birmingham Hip Resurfacing (BHR); 93=bilateral BHR; 294=unilateral Corail-Pinnacle). All patients underwent whole blood metal ion sampling. Patients were divided into those with ARMD (revised for ARMD or ARMD on imaging; n=75), and those without ARMD (n=635). Previously devised implant-specific blood metal ion thresholds (cobalt=2.15μg/l for unilateral BHR; maximum cobalt or chromium=5.5μg/l for bilateral BHR; cobalt=3.57μg/l for unilateral Corail-Pinnacle) were applied to the validation cohort, with receiver operating characteristic curve analysis used to establish the discriminatory characteristics for each respective threshold. The area under the curve, sensitivity, specificity, positive predictive value and negative predictive value for distinguishing between patients with and without ARMD for each implant-specific threshold were respectively: unilateral BHR=89.4% (95% CI=82.8%-96.0%), 78.9%, 86.7%, 44.1%, 96.9%; bilateral BHR=89.2% (95% CI=81.3%-97.1%), 70.6%, 86.8%, 54.5%, 93.0%; unilateral Corail-Pinnacle=76.9% (95% CI=63.9%-90.0%), 65.0%, 85.4%, 24.5%, 97.1%. The 7μg/l UK MHRA threshold missed significantly more patients with ARMD compared with the implant-specific thresholds (4.9% vs. 2.8%; p=0.0003). This external multi-centre validation study has confirmed that MoM hip arthroplasty patients with blood metal ion levels below newly devised implant-specific thresholds have a low-risk of ARMD. Compared to implant-specific thresholds, the currently proposed fixed MHRA threshold missed more patients with ARMD. We recommend using implant-specific thresholds over fixed thresholds when managing MoM hip arthroplasty patients.
We evaluated the short-term functional outcome and prevalence
of bearing-specific generation of audible noise in 301 patients
(336 hips) operated on with fourth generation (Delta) medium diameter
head, ceramic-on-ceramic (CoC) total hip arthroplasties (THAs). There were 191 female (63%) and 110 male patients (37%) with
a mean age of 61 years (29 to 78) and mean follow-up of 2.1 years
(1.3 to 3.4). Patients completed three questionnaires: Oxford Hip
Score (OHS), Research and Development 36-item health survey (RAND-36)
and a noise-specific symptom questionnaire. Plain radiographs were also
analysed. A total of three hips (0.9%) were revised. Aims
Patients and Methods
There are many guidelines that help direct the management of
patients with metal-on-metal (MOM) hip arthroplasties. We have undertaken
a study to compare the management of patients with MOM hip arthroplasties in
different countries. Six international tertiary referral orthopaedic centres were
invited to participate by organising a multi-disciplinary team (MDT)
meeting, consisting of two or more revision hip arthroplasty surgeons
and a musculoskeletal radiologist. A full clinical dataset including
history, blood tests and imaging for ten patients was sent to each
unit, for discussion and treatment planning. Differences in the
interpretation of findings, management decisions and rationale for
decisions were compared using quantitative and qualitative methods.Aims
Methods
We compared the length of hospitalisation, rate
of infection, dislocation of the hip and revision, and mortality following
primary hip and knee arthroplasty for osteoarthritis in patients
with Alzheimer’s disease (n = 1064) and a matched control group
(n = 3192). The data were collected from nationwide Finnish health
registers. Patients with Alzheimer’s disease had a longer peri-operative
hospitalisation (median 13 days 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:
We evaluated the duration of hospitalisation,
occurrence of infections, hip dislocations, revisions, and mortality following
primary hip and knee replacement in 857 patients with Parkinson’s
disease and compared them with 2571 matched control patients. The
data were collected from comprehensive nationwide Finnish health
registers. The mean follow-up was six years (1 to 13). The patients
with Parkinson’s disease had a longer mean length of stay (21 days
[1 to 365] Cite this article:
Previous studies from single centres or single-surgeon
series report good early and mid-term results for high tibial osteotomy
(HTO) in the treatment of osteoarthritis of the knee. However, the
survivorship of HTO at a national level is unknown. This registry-based
study included 3195 high HTOs performed between 1987 and 2008. Kaplan-Meier analysis
revealed an overall survivorship of 89% (95% confidence interval
(CI) 88 to 90) at five years and 73% (95% CI 72 to 75) at ten years,
when conversion to total knee replacement was taken as the endpoint.
Females and patients aged >
50 years had worse survivorship than
males or patients aged ≤ 50 years (hazard ratio (HR) 1.26 (95% CI
1.11 to 1.43) and HR 1.41 (95% CI 1.23 to 1.64), respectively).
The survivorship of HTOs performed between 1998 to 2008 was worse
than for those performed between 1987 and 1997.
