The main problem of infected orthopaedic implants is that the presence of microorganisms in an organized biofilm making them difficult accessible for antibiotics. This biofilm consists of a complex community of microorganisms embedded in an extracellular matrix that forms on surfaces such as an implant. Non-contact induction heating uses pulsed electromagnetic fields to induce so-called ‘eddy currents’ within metal objects which causes them to heat up. This heat causes thermal damage to the bacterial biofilm hence killing the bacteria on the metal implant. The purpose of this study is to determine the effectiveness of induction heating on killing
Administration of perioperative antibiotic prophylaxis (AP) reduces the risk of prosthetic joint infection (PJI) following primary total hip (THA) and knee (TKA) arthroplasty. The optimal type of antibiotic used, and duration of prophylaxis are subject to debate. We compared the risk of revision surgery for PJI in the first year following THA and TKA by AP regimen. A national survey collecting information on hospital-level AP regimen policy was conducted across the Netherlands and linked to data from the LROI arthroplasty registry for 2011–2015. PJI status was defined using the surgical indication reported at revision by surgeons in the registry form. Restricted cubic splines Poisson model adjusted for hospital clustering were used to conduct the comparisons on 130,712 THAs and 111,467 TKAs performed across 99 institutions. These included 399 THAs and 303 TKAs revised for an indication of PJI. Multiple shot of Cefazolin (MCZ), of cefuroxime (MCX) and single shot of Cefazolin (SCZ) were respectively administrated to 87%, 4% and 9% of patients. For THA, the rates of revision for PJI were respectively 31/10,000 person-years 95%CI[28, 35], 39[25, 59] and 23[15, 34] in the groups which received MCZ, MCX and SCZ; respectively, the rates for TKA were 27[24, 31], 40[24, 62] and 24[16, 36]. No evidence of difference between AP regimens was found in the unadjusted and adjusted model (age, gender, BMI and ASA grade). Further work is advocated to confirm whether there is an association between AP regimen collected at patient-level and the risk of subsequent revision for PJI.
Total Hip Arthroplasty (THA) and Total Knee Arthroplasty (TKA) bring relief of pain and functional disability to patients with end stage osteoarthritis, however the literature on their impact on patients’ level of physical activity (PA) is scarce. Cross-sectional study, performed in 2012, in 515 patients who underwent THA/TKA surgery in 2010–2011 and a random sample of persons aged >40 years from the Dutch general population participating in a national survey in the same period. PA in minutes per week (min/week) and adherence to the Dutch recommendation for health enhancing PA was measured by means of the Short QUestionnaire to ASsess Health enhancing PA (SQUASH) Additional assessments included socio-demographic characteristics, the presence of comorbidities, BMI and Short Form-12. Multivariable linear (total min/week) and logistic regression analyses (meeting PA recommendation), adjusting for confounders, were performed for THA and TKA separately.Objective
Methods
Backgroud: Allogeneic transfusion rates after primary hip and knee arthroplasty are used as quality indicators for hospitals, but hospital comparisons may be hampered by low event rates. Extended hospital stay is often used and may be more suitable as an alternative. This study aims to assess whether transfusion rates and extended hospital stay can be used to reliably rank hospitals. We used the baseline data from the LISBOA implementation trial, where data on patient characteristics and outcomes were collected in a sample of approximately 100 patients undergoing elective primary total hip or knee arthroplasty for each of the 23 participating hospitals. We calculated the reliability of ranking (Rankability) of transfusion rates and extended hospital stay (> 4 postoperative days), using fixed and random effects logistic regression analysis, by dividing the between-hospital variation to the sum of within and between-hospital variation. Rankability thus shows which part of the hospital differences are true differences and not due to random variation. 1163 total hip and 986 total knee procedures were assessed. After adjustment for patient characteristics the odds ratio (OR) of receiving a transfusion in a hospital after total hip ranged from 0.72 to 1.38 and from 0.30 to 3.30 in total knee. Rankability was 17% for hip and 36% for knee arthroplasty, meaning that only 17% and 36% are true hospital differences. Larger hospital variation was found for extended hospital stay (OR range [0.28–3.51] for hip and [0.10–9.95] for knee arthroplasty), and better rankability.Methods
Results
Periprosthetic osteolysis is the most common long-term complication of a total joint arthroplasty, often resulting in aseptic loosening of the implant. As we aim at developing a safe and minimally invasive implant refixation procedure, thorough characterisation of the properties of the periprosthetic tissue is needed. In this pilot study, the periprosthetic tissue of eleven patients undergoing hip revision surgery due to aseptic loosening was obtained. Histology, confocal microscopy, atomic force microscopy (AFM) and nanoindentation were performed to structurally and mechanically characterise the tissue. The study was approved by the Medical Ethical Committee of the Leiden University Medical Center.Background
Methods
Aseptic loosening of prostheses is the most common cause for failure in total joint arthroplasty. Particulate wear debris induces a non-stop inflammatory-like response resulting in the formation of a layer of fibrous periprosthetic tissue at the bone/implant interface. The current treatment is an invasive revision joint replacement surgery. However, this procedure has a high morbidity rate, therefore, a less invasive alternative is necessary. One approach could be to re-establish osseointegration of the joint prosthesis by inducing osteoblast differentiation in the periprosthetic tissue. Therefore, the aim of this study was to investigate the capacity of periprosthetic tissue cells to differentiate into the osteoblast lineage. Periprosthetic tissue samples were collected during revision surgery of aseptic loosened hip prostheses, after which cells were isolated by collagenase digestion. Of 14 different donors, cells from passage 1 till 3 were used for differentiation experiments. During 21 days, cells were cultured under normal and several osteogenic culture conditions. Cultures were stained for alkaline phosphatase (ALP) activity and mineral deposits in the extracellular matrix.Background
Methods
Osteoarthritis (OA) is a prevalent, age-related joint disease, characterized by diverse progressive changes in articular cartilage and subchondral bone. Disease management is severely hampered by the absence of tools to classify patients based on underlying disease mechanisms. For that matter, increased BMI is a known risk factor for OA in the weight bearing knee joint, but also for hand OA.1The increased risk for OA is therefore thought to be influenced by systemic factors accompanying BMI. It was hypothesized that differences in metabolic state could be underlying OA phenotypes. In the current study we set out to explore the potential role of a large range of metabolites in blood as sensitive biomarker of OA. Plasma samples were taken from the Rotterdam Study, CHECK-, GARP/NORREF- and the LUMC-arthroplasty cohorts. OA was defined as having had arthroplasty for primary OA, stratified per location (any, hip or knee). In total 647 persons with Total Joint Arthroplasty (TJA) were included and 2125 persons were considered as controls (i.e. they had a Kellgrenn-Lawrence Score of <2 indicating no radiographic OA was present) in any of the studied joints. A total of 231 different metabolites were assessed by using the BrainShake NMR platform. Since parts of the metabolites were highly correlated, we used Principal Component Analyses (PCA) to reduce the data. 23 factors were identified, accounting for 91,4% of the variance in the data. Logistic regression models were applied to investigate the identified factors for their association to arthroplasty for primary OA, independent of age, sex, BMI and cholesterol-lowering medication (statins). The models showed two different factors robustly associated to arthroplasty as result of primary OA. A table represents the associations of these factors to arthroplasty adjusted for age, sex and BMI, as the information on statin-use was not known for all subjects. Analyses showed that additional correction for statins did not change the results. When stratifying the arthroplasty phenotypes for joint location, factor 11, characterized by e.g. linoleic acid, was found to be associated to arthroplasty in the hip (THA). Similarly, Factor 22, representing saturated fatty acids and degree of unsaturation, was consistently associated with arthroplasty, independent of the site. When analyzing the metabolites involved in the factors individually these associations were confirmed for most contributors of the factors, except the ratio of saturated fatty acids to total fatty acids. Our preliminary analyses showed that persons with arthroplasty for primary OA compared to controls have different values for factors composed for fatty acids. The identification of groups of fatty acid metabolites as being connected to OA phenotypes indicates an inflammation driven pathway which might give a better understanding of the mechanisms behind OA.
