In vivo assessment of TiO2 based wear nanoparticles in periprosthetic tissues.

A multimodal approach combining inductively coupled plasma mass spectrometry (ICP-MS), single-particle ICP-MS (spICP-MS), scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDS) and Raman spectroscopy enabled a deeper insight into the balance between total titanium (Ti), the soluble titanium fraction and titanium dioxide based particle fraction levels in periprosthetic tissues collected from patients undergoing revision surgery. Hydrofluoric acid usage in the sample digestion allowed for complete digestion of TiO2 particles, thus enabling accurate estimation of total Ti levels. The TiO2 fraction represents 38-94% of the titanium load in the six samples where particles were detected, and the fraction is present mainly in samples from patients with aseptically loosened total hip arthroplasty. Further attention was given to this fraction determining the elemental composition, particle count, particle size and modification of TiO2. The spICP-MS analysis confirmed the presence of the TiO2-derived (nano)particles (NPs) with a 39- to 187-nm median size and particle count up to 2.3 × 1011 particles per gram of tissue. On top of that, the SEM-EDS confirmed the presence of the TiO2 nanoparticles with 230-nm median size and an anatase crystal phase was determined by Raman spectroscopy. This study presents a novel multimodal approach for TiO2 particle determination and characterization in tissue samples and is the first in vivo study of this character.

Macrophage Polarization and the Osteoimmunology of Periprosthetic Osteolysis.

PURPOSE OF REVIEW: Joint replacement has revolutionized the treatment of end-stage arthritis. We highlight the key role of macrophages in the innate immune system in helping to ensure that the prosthesis-host interface remains biologically robust. RECENT FINDINGS: Osteoimmunology is of great interest to researchers investigating the fundamental biological and material aspects of joint replacement. Constant communication between cells of the monocyte/macrophage/osteoclast lineage and the mesenchymal stem cell-osteoblast lineage determines whether a durable prosthesis-implant interface is obtained, or whether implant loosening occurs. Tissue and circulating monocytes/macrophages provide local surveillance of stimuli such as the presence of byproducts of wear and can quickly polarize to pro- and anti-inflammatory phenotypes to re-establish tissue homeostasis. When these mechanisms fail, periprosthetic osteolysis results in progressive bone loss and painful failure of mechanical fixation. Immune modulation of the periprosthetic microenvironment is a potential intervention to facilitate long-term durability of prosthetic interfaces.

A theoretical model of health management using data-driven decision-making: the future of precision medicine and health.

BACKGROUND: The burden of chronic and societal diseases is affected by many risk factors that can change over time. The minimalisation of disease-associated risk factors may contribute to long-term health. Therefore, new data-driven health management should be used in clinical decision-making in order to minimise future individual risks of disease and adverse health effects. METHODS: We aimed to develop a health trajectories (HT) management methodology based on electronic health records (EHR) and analysing overlapping groups of patients who share a similar risk of developing a particular disease or experiencing specific adverse health effects. Formal concept analysis (FCA) was applied to identify and visualise overlapping patient groups, as well as for decision-making. To demonstrate its capabilities, the theoretical model presented uses genuine data from a local total knee arthroplasty (TKA) register (a total of 1885 patients) and shows the influence of step by step changes in five lifestyle factors (BMI, smoking, activity, sports and long-distance walking) on the risk of early reoperation after TKA. RESULTS: The theoretical model of HT management demonstrates the potential of using EHR data to make data-driven recommendations to support both patients' and physicians' decision-making. The model example developed from the TKA register acts as a clinical decision-making tool, built to show surgeons and patients the likelihood of early reoperation after TKA and how the likelihood changes when factors are modified. The presented data-driven tool suits an individualised approach to health management because it quantifies the impact of various combinations of factors on the early reoperation rate after TKA and shows alternative combinations of factors that may change the reoperation risk. CONCLUSION: This theoretical model introduces future HT management as an understandable way of conceiving patients' futures with a view to positively (or negatively) changing their behaviour. The model's ability to influence beneficial health care decision-making to improve patient outcomes should be proved using various real-world data from EHR datasets.

Gender Differences in Contribution of Smoking, Low Physical Activity, and High BMI to Increased Risk of Early Reoperation After TKA.

BACKGROUND: The reliable preoperative identification of patients at a high risk of early reoperations (<2 years after primary surgery) after total knee arthroplasty (TKA) could lead to adjustments of the surgical procedure and counseling, thus lowering the percentage of revision surgeries. METHODS: The unselected cohort consisted of 1885 patients (695 men and 1190 women) who underwent TKA implantation between September 2010 and April 2017 at a single tertiary orthopedic center. Multivariate patient similarity networks were applied to identify patient groups at a high risk of early reoperations based on 25 preoperative parameters. RESULTS: Early reoperations (109 cases, 5.8%) were less frequent in women (4.4%; median time to reoperation, 2.0 months) than in men (8.2%; 7.5 months), reaching the highest incidence in younger men (10.9%; <66 years). Of the tested preoperative parameters, the risk of reoperation in men was more likely associated with smoking or obesity (body mass index [BMI] > 30). In women, low physical activity and high BMI were the most likely risk factors for early reoperations. Other factors did not affect the risk of early reoperations, including the primary diagnosis, comorbidities, and surgeon-implanting TKA. CONCLUSION: This study demonstrates the effect of smoking, physical activity, and BMI on the risk of early reoperation after TKA, with the different contribution in men/women. Identification of patient subgroups with a higher risk of early revision after TKA is needed for clinical implementation of precision medicine in orthopedics.

[Nutraceuticals in therapy of knee osteoarthritis: orthopaedic view]. / Nutraceutika v terapii gonartrózy: pohled ortopeda.

Knee osteoarthritis is one of the most frequent diagnoses of load-carrying joints encountered in orthopaedic surgeons offices. Depending on the clinical stage, the therapy starts with conservative treatment. Corrective osteotomy is indicated in younger patients without an extensive and serious impairment. Implantation of TKR (total knee replacement) is usually indicated in more advanced stages. One of the pillars of conservative therapy is analgesics and non-steroidal antirheumatic drugs. A specific group consists of perorally administered drugs for suppression of symptoms or even deceleration of knee osteoarthrosis. These products are popular mainly thanks to their good tolerance and minimal side effects. The clinical effect ranges between minimal and medium depending on the degree of osteoarthrosis, type of drug and study. Similar to rheumatologists, orthopaedic surgeons also find it difficult to identify candidates suitable for a particular type of therapy, except indication for TKR. By all means, nutraceuticals are still considered part of clinical practice.Key words: chondroitin sulphate - glucosamine sulphate - knee osteoarthrosis - methylsulfonylmethane - nutraceuticals - pharmaceutical intervention.

Detection of Prosthetic Joint Infection Based on Magnetically Assisted Surface Enhanced Raman Spectroscopy.

Accurate and rapid diagnosis of prosthetic joint infection (PJI) is vital for rational and effective therapeutic management of this condition. Several diagnostic strategies have been developed for discriminating between infected and noninfected cases. However, none of them can reliably diagnose the whole spectrum of clinical presentations of PJI. Here, we report a new method for PJI detection based on magnetically assisted surface enhanced Raman spectroscopy (MA-SERS) using streptavidin-modified magnetic nanoparticles (MNP@Strep) whose surface is functionalized with suitable biotinylated antibodies and then coated with silver nanoparticles by self-assembly. The high efficiency of this approach is demonstrated by the diagnosis of infections caused by two bacterial species commonly associated with PJI, namely, Staphylococcus aureus and Streptococcus pyogenes. The method's performance was verified with model samples of bacterial lysates and with four real-matrix samples of knee joint fluid spiked with live pathogenic bacterial cells. This procedure is operationally simple, versatile, inexpensive, and quick to perform, making it a potentially attractive alternative to established diagnostic techniques based on Koch's culturing or colony counting methods.

Excellent Diagnostic Characteristics for Ultrafast Gene Profiling of DEFA1-IL1B-LTF in Detection of Prosthetic Joint Infections.

The timely and exact diagnosis of prosthetic joint infection (PJI) is crucial for surgical decision-making. Intraoperatively, delivery of the result within an hour is required. Alpha-defensin lateral immunoassay of joint fluid (JF) is precise for the intraoperative exclusion of PJI; however, for patients with a limited amount of JF and/or in cases where the JF is bloody, this test is unhelpful. Important information is hidden in periprosthetic tissues that may much better reflect the current status of implant pathology. We therefore investigated the utility of the gene expression patterns of 12 candidate genes (TLR1, -2, -4, -6, and 10, DEFA1, LTF, IL1B, BPI, CRP, IFNG, and DEFB4A) previously associated with infection for detection of PJI in periprosthetic tissues of patients with total joint arthroplasty (TJA) (n = 76) reoperated for PJI (n = 38) or aseptic failure (n = 38), using the ultrafast quantitative reverse transcription-PCR (RT-PCR) Xxpress system (BJS Biotechnologies Ltd.). Advanced data-mining algorithms were applied for data analysis. For PJI, we detected elevated mRNA expression levels of DEFA1 (P < 0.0001), IL1B (P < 0.0001), LTF (P < 0.0001), TLR1 (P = 0.02), and BPI (P = 0.01) in comparison to those in tissues from aseptic cases. A feature selection algorithm revealed that the DEFA1-IL1B-LTF pattern was the most appropriate for detection/exclusion of PJI, achieving 94.5% sensitivity and 95.7% specificity, with likelihood ratios (LRs) for positive and negative results of 16.3 and 0.06, respectively. Taken together, the results show that DEFA1-IL1B-LTF gene expression detection by use of ultrafast qRT-PCR linked to an electronic calculator allows detection of patients with a high probability of PJI within 45 min after sampling. Further testing on a larger cohort of patients is needed.

Antibacterial surface treatment for orthopaedic implants.

It is expected that the projected increased usage of implantable devices in medicine will result in a natural rise in the number of infections related to these cases. Some patients are unable to autonomously prevent formation of biofilm on implant surfaces. Suppression of the local peri-implant immune response is an important contributory factor. Substantial avascular scar tissue encountered during revision joint replacement surgery places these cases at an especially high risk of periprosthetic joint infection. A critical pathogenic event in the process of biofilm formation is bacterial adhesion. Prevention of biomaterial-associated infections should be concurrently focused on at least two targets: inhibition of biofilm formation and minimizing local immune response suppression. Current knowledge of antimicrobial surface treatments suitable for prevention of prosthetic joint infection is reviewed. Several surface treatment modalities have been proposed. Minimizing bacterial adhesion, biofilm formation inhibition, and bactericidal approaches are discussed. The ultimate anti-infective surface should be "smart" and responsive to even the lowest bacterial load. While research in this field is promising, there appears to be a great discrepancy between proposed and clinically implemented strategies, and there is urgent need for translational science focusing on this topic.

Coding variants of TLR2 and TLR4 genes do not substantially contribute to prosthetic joint infection.

OBJECTIVE AND DESIGN: Prosthetic joint infection (PJI) is a severe complication of total joint arthroplasty (TJA). We conducted a genetic association study that investigated whether selected coding variants of the genes for Toll-like receptors (TLR)2 and TLR4 may contribute to genetic susceptibility for PJI. SUBJECTS AND METHODS: In total, 350 patients with TJA (98 with PJI/252 without PJI), and 189 unrelated healthy Czech individuals without TJA were enrolled in our study. Three missense polymorphisms of the genes encoding for TLR2 (TLR2 R753Q, rs5743708) and TLR4 (TLR4 D299G, rs4986790 and T399I, rs4986791) were genotyped by "TaqMan" assay. RESULTS: The frequencies of less common variants for the investigated TLR2/TLR4 polymorphisms in healthy individuals were similar to those observed in other Caucasian populations. Importantly, the distribution of TLR2/TLR4 genotype alleles did not differ between the patients with PJI and the control groups of patients with nonseptic prostheses/healthy individuals. CONCLUSION: Our data suggest that structural genetic variants of the receptors TLR2 and TLR4 do not substantially affect the risk of prosthetic joint infection.

Long-term survival of the uncemented Balgrist total hip replacement cup.

PURPOSE: The purpose of this study was to evaluate the long-term clinical and radiographic outcomes of the Balgrist total hip replacement cup. METHODS: We report the results of a retrospective review of 195 total hip prostheses with Balgrist cup implanted in 178 patients. There were 59 men and 119 women with a mean age at surgery of 52.3 years (range, 19-72). Cox regression was used to determine the influence of independent variables on the survivorship of the prosthesis. RESULTS: There were 117 (66 %) of 178 patients, and 131 (67 %) of 195 hips available for assessment at a mean follow-up of 17.4 years. A total of 21 patients (22 hips) were lost from follow-up (12 %). A total of 25 patients (27 hips) required some type of re-operation during the follow-up period. Eight of 27 re-operations (30 %) were directly caused by the Balgrist cup failure due to fatigue fracture of the metallic shell (n = 5; 19 %), polyethylene wear (n = 2; 7 %) and aseptic loosening (n = 1; 4 %). The mean polyethylene wear rate was 0.068 mm/year (range, 0.008-0.230; SD = 0.043). The risk of re-operation for any reason was decreased with dysplastic hip as a primary diagnosis (hazard ratio; HR = 0.250; 95 % CI 0.086-0.725) and with greater age at the time of surgery (HR = 0.923; 95 % CI 0.880-0.969). The 19-year survivorship with re-operation for any reason was 75.6 % (95 % CI 67.0-84.2). The 19-year survivorship with re-operation for the Balgrist cup failure was 90.5 % (95 % CI 83.4-97.6). CONCLUSIONS: The Balgrist cup continues to provide excellent clinical and radiological outcomes. This is associated at least in part with a low polyethylene wear rate. The main reason for the Balgrist cup failure is fatigue fracture of the metallic shell.

Friend or foe? Inflammation and the foreign body response to orthopedic biomaterials.

The use of biomaterials and implants for joint replacement, fracture fixation, spinal stabilization and other orthopedic indications has revolutionized patient care by reliably decreasing pain and improving function. These surgical procedures always invoke an acute inflammatory reaction initially, that in most cases, readily subsides. Occasionally, chronic inflammation around the implant develops and persists; this results in unremitting pain and compromises function. The etiology of chronic inflammation may be specific, such as with infection, or be unknown. The histological hallmarks of chronic inflammation include activated macrophages, fibroblasts, T cell subsets, and other cells of the innate immune system. The presence of cells of the adaptive immune system usually indicates allergic reactions to metallic haptens. A foreign body reaction is composed of activated macrophages, giant cells, fibroblasts, and other cells often distributed in a characteristic histological arrangement; this reaction is usually due to particulate debris and other byproducts from the biomaterials used in the implant. Both chronic inflammation and the foreign body response have adverse biological effects on the integration of the implant with the surrounding tissues. Strategies to mitigate chronic inflammation and the foreign body response will enhance the initial incorporation and longevity of the implant, and thereby, improve long-term pain relief and overall function for the patient. The seminal research performed in the laboratory of Dr. James Anderson and co-workers has provided an inspirational and driving force for our laboratory's work on the interactions and crosstalk among cells of the mesenchymal, immune, and vascular lineages, and orthopedic biomaterials. Dr. Anderson's delineation of the fundamental biologic processes and mechanisms underlying acute and chronic inflammation, the foreign body response, resolution, and eventual functional integration of implants in different organ systems has provided researchers with a strategic approach to the use of biomaterials to improve health in numerous clinical scenarios.

Detailed insight into chromium species released from failed CoCrMo implants: Ex vivo periprosthetic tissues study.

This unique study provides information on Cr species and their distribution in periprosthetic tissues of patients with metal-on-polyethylene joint implants. Co-Cr-Mo alloy has been widely used in joint replacement and represents a source of metal derived species. In the case of chromium, previous studies on periprosthetic tissues revealed mainly Cr(III) distribution, whereas the potential release of carcinogenic Cr(VI) species has been still a subject of debate. Here, an analytical approach utilizing speciation and fractionation was developed to analyze periprosthetic tissue samples collected from wide range of patients with failed total hip or knee replacements. The results reveal that Cr(III) is mainly released in the form of insoluble CrPO4 and Cr2 O3 particles. The highest Cr contents were found in periprosthetic tissues of patients suffering from aseptic loosening and having more Cr-based implants in the body. Cr species penetrated tissue layers, but their levels decreased with the distance from an implant. The detailed speciation/fractionation study carried out using the set of consecutive periprosthetic tissues of a patient with extensive metallosis showed the presence of trace amounts of free Cr(III), nanoparticles, and metal-protein complexes, but the majority of Cr still occurred in CrPO4 form. Carcinogenic Cr(VI) species were not detected. Up to date, there is no published human tissue study focused on the detailed speciation of both soluble and insoluble Cr-based species in the context of failing total hip and knee replacements.

Variation in the IL1B, TNF and IL6 genes and individual susceptibility to prosthetic joint infection.

BACKGROUND: Prosthetic joint infection (PJI) is an important failure mechanism of total joint arthroplasty (TJA). Here we examine whether the particular genetic variants can lead to increased susceptibility to PJI development. RESULTS: We conducted a genetic-association study to determine whether PJI could be associated with functional cytokine gene polymorphisms (CGP) influencing on innate immunity response. A case-control design was utilized and previously published criteria for PJI were included to distinguish between cases and control subjects with/without TJA. Six single nucleotide polymorphisms (SNPs) located in the genes for interleukin-1beta (SNP: IL1B-511, +3962), tumour necrosis factor alpha (TNF-308, -238) and interleukin-6 (IL6-174, nt565) were genotyped in 303 Caucasian (Czech) patients with TJA (89 with PJI / 214 without PJI), and 168 unrelated healthy Czech individuals without TJA. The results showed that carriers of the less common IL1B-511*T allele were overrepresented in the group of TJA patients with PJI (69%) in comparison with those that did not develop PJI (51%, p = 0.006, p(corr) = 0.037) and with healthy controls (55%, p = 0.04, p(corr) = N.S.). There was no significant difference in the distribution of the remaining five investigated CGPs and their haplotypes between groups. CONCLUSION: A functional variant of the gene encoding for IL-1beta was preliminarily nominated as a genetic factor contributing to the susceptibility to PJI. Our results should be independently replicated; studies on the functional relevance of IL1B gene variants in PJI are also needed.

Combined and intravenous administration of TXA reduces blood loss more than topical administration in primary total knee arthroplasty: A randomized clinical trial.

AIM: To determine the most effective administration of tranexamic acid (TXA) in patients with primary total knee arthroplasty (TKA). MATERIAL AND METHOD: We enrolled a total of 400 patients (154 men and 346 women) in this randomized trial (4 groups, each of 100 patients). The first group (IV1) had a single intravenous dose (15 mg TXA/kg) prior to skin incision. Group 2 (IV2) had TXA in 2 intravenous doses (15 mg TXA/kg): prior to skin incision and 6 hours after the first dose. Group 3 (TOP) had 2 g TXA in 50 mL of saline irrigated topically at the end of the surgery. The fourth group (COMB) combined IV1 and TOP regimens. We monitored the amount of total blood loss (TBL), haemoglobin drop, use of blood transfusions (BTs), and complications in each patient. RESULTS: The amount of TBL was significantly lower in IV1, IV2 and COMB regimens compared to the TOP (P<0.0001). The lowest decrease in haemoglobin within 12 hours after surgery was observed in intravenous regimens (P=0.045). A significant difference in haemoglobin decrease on day 1 after the surgery was demonstrated in the COMB and intravenous regimens (P=0.011). CONCLUSION: In primary TKA, it is preferable to administer TXA intravenously in two doses or in a combined regimen. Simple topical administration of TXA was not as effective and is indicated only in cases where systemic administration of TXA is contraindicated. No substantial complications occurred in either group of patients.

[Preoperative diagnosis of prosthetic joint infection]. / Predoperacní diagnostika infekcí kloubních náhrad.

Making pre-operative diagnosis of intermediate and low-grade infections of prosthetic joint infection (PJI) is demanding and requires both clinical experience and good knowledge of diagnostic test performance. It is also necessary to know the rules of working with diagnostic tests based on the expected change in pre-test probability of PJI or the diagnostic odds ratio. This also requires a multi-modal approach with a rational combination of relevant tests because none of them can have both 100% sensitivity and 100% specificity. Suspicion of a developing PJI should be aroused by relevant information present in the patient s medical history and confirmed by clinical examination. Patients with an increased starting PJI probability, i.e. after taking the medical history and clinical examination, should be examined for the erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels (screening tests). When both of these tests are positive and no other alternative explanation for their increase is plausible, then the post-test probability of PJI is significantly increased (up to 70%). Under such conditions the diagnosis is made definitive by positive results of synovial fluid analysis (leukocyte count, percentage of neutrophils and lymphocytes, IL-1, IL-6) or an increased IL-6 serum levels. On the other hand, when both ESR and CRP are negative, the post-test probability of PJI is significantly decreased and no further examination for the presence of infection is usually necessary. In case of inconsistent results of ESR and CRP or if there is a high suspicion of joint infection regardless of these test results, joint fluid aspiration (cytology, IL-1, IL-6) and IL-6 serum levels should be assessed. In this situation scintigraphy imaging (three-phase bone scan combined with labelled leukocytes or anti-granulocyte antibodies) can also support or exclude the diagnosis. In low-grade infections or after previous administration of antibiotics it is recommended to repeat the above-mentioned laboratory tests and joint aspiration after at least a two-week interval without antibiotics. Key words: Total joint arthroplasty, prosthetic joint infection, preoperative diagnosis, pre-test probability, post-test probability, algorithm.

The number of lymphocytes increases in the periprosthetic tissues with increasing time of implant service in non-metal-on-metal total joint arthroplasties: A role of metallic particles?

BACKGROUND: The objective of the study was to determine the association between periprosthetic concentrations of selected metals and changes induced in periprosthetic tissues (PT). METHODS: PT from 24 patients with metal-on-polyethylene or ceramic-on-polyethylene total joint replacements (TJRs) were examined. Samples underwent histological examination including quantification of cellular populations. Determination of metals was performed according to the published methodology. Results were processed using correlation analysis and Principal Component Analysis (PCA), respectively. RESULTS: Growing concentration of metals in the PT was found as a function of length of exposure (LoE). Differences in Ti, Co, Cr and V concentrations (per α = 0.05) depended on the type of alloy the implants were made from. On the contrary, the implant composition did not reflect in the different numbers of immune cells per 1 high power field, not even in distribution of the membrane type according to the Krenn classification. PCA revealed several clusters in dependence on the LoE, type of the membrane and presence of immune cells. High representation of lymphocytes in the PT was typical for clusters with the longest LoE while a higher representation of neutrophils was typical for a shorter time to reoperation. CONCLUSIONS: Correlation between the LoE and concentrations of metals in its surroundings was demonstrated. However, the tissue image analysis cannot differentiate finer, potentially metal-induced tissue changes. Importantly, the tissues become more similar with an increasing LoE. We draw a conclusion about predominantly non-specific stimulation of the PT jointly by metal and polyethylene particles in non-metal-on-metal TJRs.

Specific detection of Staphylococcus aureus infection and marker for Alzheimer disease by surface enhanced Raman spectroscopy using silver and gold nanoparticle-coated magnetic polystyrene beads.

Targeted and effective therapy of diseases demands utilization of rapid methods of identification of the given markers. Surface enhanced Raman spectroscopy (SERS) in conjunction with streptavidin-biotin complex is a promising alternative to culture or PCR based methods used for such purposes. Many biotinylated antibodies are available on the market and so this system offers a powerful tool for many analytical applications. Here, we present a very fast and easy-to-use procedure for preparation of streptavidin coated magnetic polystyrene-Au (or Ag) nanocomposite particles as efficient substrate for surface SERS purposes. As a precursor for the preparation of SERS active and magnetically separable composite, commercially available streptavidin coated polystyrene (PS) microparticles with a magnetic core were utilized. These composites of PS particles with silver or gold nanoparticles were prepared by reducing Au(III) or Ag(I) ions using ascorbic acid or dopamine. The choice of the reducing agent influences the morphology and the size of the prepared Ag or Au particles (15-100 nm). The prepare composites were also characterized by HR-TEM images, mapping of elements and also magnetization measurements. The content of Au and Ag was determined by AAS analysis. The synthesized composites have a significantly lower density against magnetic composites based on iron oxides, which considerably decreases the tendency to sedimentation. The polystyrene shell on a magnetic iron oxide core also pronouncedly reduces the inclination to particle aggregation. Moreover, the preparation and purification of this SERS substrate takes only a few minutes. The PS composite with thorny Au particles with the size of approximately 100 nm prepared was utilized for specific and selective detection of Staphylococcus aureus infection in joint knee fluid (PJI) and tau protein (marker for Alzheimer disease).