Tribological behavior of shape-specific microplate-enriched synovial fluids on a linear two-axis tribometer

Nano-and micro-particles are being increasingly used to tune interfacial frictional properties in diverse applications,from friction modifiers in industrial lubrication to enhanced biological fluids in human osteoarthritic joints.Here,we assessed the tribological properties of a simulated synovial fluid enriched with non-spherical,poly lactic-co-glycolic acid(PLGA)microparticles(μPL)that have been previously demonstrated for the pharmacological management of osteoarthritis(OA).Three different μPL configurations were fabricated presenting a 20μm×20μm square base and a thickness of 5μm(thin,5H μPL),10μm(10H μPL),and 20μm(cubical,20H μPL).After extensive morphological and physicochemical characterizations,the apparent Young’s modulus of the μPL was quantified under compressive loading returning an average value of~6 kPa,independently of the particle morphology.Then,using a linear two-axis tribometer,the static(μ_(s))and dynamic(μ_(d))friction coefficients of the μPL-enriched simulated synovial fluid were determined in terms of particle configuration and concentration,varying from 0(fluid only)to 6×10^(5) μPL/mL.The particle morphology had a modest influence on friction,possibly because the μPL were fully squeezed between two mating surfaces by a 5.8 N normal load realizing boundary-like lubrication conditions.Differently,friction was observed to depend on the dimensionless parameterW,defined as the ratio between the total volume of the μPL enriching the simulated synovial fluid and the volume of the fluid itself.Both coefficients of friction were documented to grow withWreaching a plateau of μ_(s)~0.4 and μ_(d)~0.15,already at Ω~2×10^(-3).Future investigations will have to systematically analyze the effect of sliding velocity,normal load,and rigidity of the mating surfaces to elucidate in full the tribological behavior of μPL in the context of osteoarthritis.

Tribological and electrochemical studies on biomimetic synovial fluids

In this study, tribological and electrochemical performances of the new biomimetic synovial fluids were studied according to different composition concentrations, including hyaluronic acid, albumin and alendronic acid sodium. By using Taguchi method, the composition contents of the biomimetic synovial fluids were designed. Items such as friction coefficient, mean scar diameter and viscosity were investigated via a four-ball tribo-tester, viscosity meter and optical microscope. Polarization studies were carried out to analyze the electrochemical behaviour of the fluids. Results showed that hyaluronic acid dominates the viscosity of the fluids. High albumin concentration will reduce friction, while increasing wear rate due to the electro-chemical effect. Alendronic acid sodium is found to reduce the biocorrosion of CoCrMo as well as provide better lubricating. In conclusion, biomimetic synovial fluids partially recover the functions of natural synovial fluids and provide good lubricating property.

Studies of Some Components in Synovial Fluid of Carpus and Tarsus in Cows

The concentrations of protein, calcium, phosphorus and glucose of the synovial fluid in the carpus and tarsus were studied in 6 health Holstein cows by the conventional techniques. and the results were compared with the contents in the serum. The results were as follows:1).There was no significant difference between left and right joints. 2).The contents of total protein, albumin, globulin in carpus were lower than that in tarsus but no significant difference. 3).The contents of protein, phosphorus and glucose in the serum were significant higher than that in synovia. However, the content of calcium in the serum was significant lower than that in synovia.

Preliminary Ferrographic Study of the Wear Particles in Synovial Fluid of Human Knee Joints

The technique of ferrography has been applied to study the wear particles in synovial fluid of human knee joints. As a result some discrete, identifiable kinds of wear particles were found and various wear mechanisms, for example, adhesive wear, fatigue wear,etc. were revealed. Ferrographic techique may provide a method for early differential diagnosis, and prognostication concerning the future course of the disease.

The VEGF production by dedifferentiated chondrocytes under synovial fluid stimulation from coxarthrosis and femoral neck fracture patients

Objective To investigate the vascular endothelial growth factor(VEGF)expression level by chondrocytes isolated from patients with osteoarthritis (OA) in hip or femoral neck fracture (FNF) and explore the effect of synovial fluid from OA

Synovial Joint Study

The impact of certain separate characteristics, including the porosity parameter, reaction rate parameter, and viscoelastic parameters of steady convective diffusion across a rectangular channel, has been investigated in this article. The model’s momentum and concentration equations were developed using the similarities technique, and the numerically finite volume method was combined with the Beavers and Joseph slip conditions. Various graphs have been used to get insight into various parameters of the problem on velocity and concentration. The cartilage surfaces are assumed to be porous, and the viscosity of synovial fluid varies with hyaluronate (HA) content.

Exposure to Hyaluronan and Radon-Containing Water during the Treatment of Periodontal Pockets

Hyaluronic acid (HA) preparations have emerged as pivotal components in contemporary dentistry, gaining widespread recognition for their multifaceted roles in various biological functions. Extensive literature underscores the significance of HA in maintaining tissue water balance, fostering cell proliferation, promoting rapid cell migration, influencing cell differentiation during organism development, and facilitating tissue regeneration. Notably, HA’s interactions with cell surface receptors contribute to the viscosity of synovial fluid, activate the immune system, and enhance cartilage elasticity. Beyond these established functions, HA has also been investigated for its potential involvement in determining and studying the hormetic effects of radon water, adding a novel dimension to its applications in dental research. A thorough exploration of existing studies reveals a nuanced understanding of how HA interventions impact the outcomes of dental procedures. The comprehensive scope of these investigations allows for a more accurate assessment of the potential effectiveness of specific interventions and provides valuable insights into post-procedural prognoses for individual patients. This synthesis of literature serves as the foundation for elucidating the intricate interplay between HA, radon exposure, and their relevance in modern dental practices.

Experimental study on boundary lubricity of superficial area of articular cartilage and synovial fluid

The boundary lubrication mechanism at the articulating surface of natural synovial joints has been the subject of much discussion in tribology.In this study,to elucidate the lubricating function of the superficial area of articular cartilage and synovial fluid(SF),cartilage specimens were processed with four different treatments:gentle and severe washing with detergent,incubation in NaCl solution,and trypsin digestion to selectively remove certain constituents from the cartilage surface.Subsequently,the frictional characteristics were examined in phosphate-buffered saline(PBS)and SF against glass.Angularly reciprocating sliding tests with a spherical glass probe and square articular cartilage specimens were performed at low contact loads in the mN range to extract the frictional behavior in the superficial area of the cartilage specimens.Meanwhile,the cartilage surface was observed to confirm the effects of treatments on the morphology of the cartilage surface using a fluorescence microscope and water-immersion methods.The coefficient of friction(COF)of the prepared cartilage specimens was varied from 0.05 to over 0.3 in PBS.However,a certain group of cartilage specimens exhibited a low COF of less than 0.1 with limited variation.For the low COF group of specimens,all four treatments increased the COF in PBS to different extents,and fluorescence microscopy revealed that the integrity of the cartilage surface was deteriorated by treatments.This means that the intact cartilage surface had lubricating constituents to maintain low friction,and the removal of such constituents resulted in the loss of the intrinsic boundary lubricity of the cartilage surface.The variation in the COF of the cartilage specimens was suppressed in SF because it had a clear boundary lubrication effect on the cartilage surface.The lubricating effect of SF could be confirmed even after degenerative treatment.

New experimental methodology to evaluate lubrication properties of synovial fluid containing worn tissue particles in osteoarthritis patients

Studying the lubrication properties of osteoarthritis(OA)synovial fluid(SF)enables an understanding of the boundary lubrication joint,mobility,and friction.However,tribology has never been combined with the clinical reality of the presence of worn particles within the synovial fluid and how they affect the osteoarthritic joints.Part of the problem relates to the tribology methods studying friction by applying inadequate pin-on-disc techniques.In this study,synovial fluid with and without worn particles was studied using a customized tribometer.This method enables opening the contact at the end of each cycle and simulates better contact conditions of a natural knee joint and can thus be applied for evaluating the severity of joint OA and the treatment given to the patient.

The Studies of Cellular Constituents in Siynovial Fluid of Carpusand Tarsus in cows

The cellular constituents of the carpus and tarsus were investigated in 6 healthy Holstein cows.The cell counts method in synovial fluid was founded.The differential leukocyte contes were made from smears stained with Wright's and Giemsa's compound stain.There were four types of cells in the synovial fluid,i.e,lymphocytes,neutrophils,macrophages and degenerated cells.The percentages of neutrophils in the synovial fluid was significantly lower than that in the bolld.The eosinophils and basophils were never observed in the smear.

Expression of Dickkopf-related Protein 1 in Patients with Temporomandibular Osteoarthritis after Treatment with Hyaluronic Acid

We previously reported that the increased expression of Dickkopf-related protein 1(DKK1)is positively related to vascular endothelial growth factor in the synovial fluid from patients with temporomandibular joint disorders(TMDs).DKK1 is involved in angiogenic activities in the TMD synovium in vitro,but the expression of DKK1 after treatment of TMD-osteoarthritis(TMD-OA)with hyaluronic acid(HA)remains unknown.In this study,we assessed the expression of DKK1 in the synovial fluid of TMD-OA patients before and after treatment with HA via enzyme-linked immunosorbent assay.We also investigated the role of DKK1 in TMD-OA via immunohistochemical staining.The relationship between the expression of DKK1 and the clinicopathological characteristics was determined by Pearson analysis.The results showed that the expression of DKK1 was significantly decreased after treatment with HA.Correlation analyses indicated that the expression of DKK1 in the TMD-OA samples was closely correlated with mouth opening and pain.These findings suggest that DKK1 could play an important role in the pathogenesis and treatment of TMD.Reduction of the pain by HA treatment may be correlated with the decreased expression of DKK1.

Role of joint aspiration before re-implantation in patients with a cement spacer in place

BACKGROUND The usefulness of a mandatory joint aspiration before re-implantation in patients with a cement spacer already in place is unclear.AIM To evaluate the role of culturing synovial fluid obtained by joint aspiration before re-implantation in patients who underwent a two-stage septic revision.METHODS A retrospective observational study was conducted,including patients that underwent a two-stage septic revision(hip or knee)from 2010 to 2017.After the first stage revision and according to intraoperative culture results,all patients were treated with an antibiotic protocol for 6-8 wk.Following 2 wk without antibiotics,a culture of synovial fluid was obtained.The results of these cultures were recorded and compared with cultures obtained during re-implantation surgery.RESULTS Forty-one patients(20 hip and 21 knee spacers)were included in the final analysis.In 39 cases,the culture of synovial fluid was negative,while in the remaining 2 cases(knee spacers)no analysis was possible due to dry tap.In 5 of the patients,two or more intraoperative cultures taken during the re-implantation surgery were positive.CONCLUSION We found no evidence to support mandatory joint aspiration before re-implantation in patients with a cement spacer in place.

Dietary Cucumis melo Reduces Markers of Muscle and Articular Inflammation Following High-intensity Exercise in Horses

We evaluated the antioxidative and anti-inflammatory potential of daily oral supplementation with a proprietary powdered Cucumis melo pulp(CMP)on exercise-induced markers of articular and muscular oxidative stress and inflammation in 12 horses.Horses performed a high-intensity exercise test immediately prior to,and then following,3 weeks of daily supplementation of 1 g powdered CMP(CMP;n=8).Controls(Co;n=8)underwent the same exercise and sampling regime but were not supplemented.Blood and synovial fluid(SF)samples were taken 24 h prior to exercise(BL),and at 1 and 24 h following exercise.Plasma and SF were analysed for prostaglandin E2(PGE2),total antioxidant status(TAS),nitrite and superoxide dismutase(SOD)activity.SF was analysed for glycosaminoglycans(GAG),and plasma was analysed for thiobarbituric acid reactive substances(TBARS).Comparisons were made using repeated measures with the initial exercise test as a covariate.There was an increase in SF SOD activity in the CMP group.Compared to Co at 1 h,CMP reduced nitrite and GAG in SF,as well as maintained plasma TAS and lymphocyte levels.At 24 h,plasma PGE2 and creatine kinase were lower in horses receiving CMP.Three weeks of supplementation with CMP reduced markers of articular and skeletal muscle oxidative stress and inflammation in response to high-intensity exercise in horses.Nutritive antioxidants may provide a useful adjunct to the daily nutrition plan of horses undergoing regular exercise training and competition.

Avalidated HPLC method for the determination of cefazolin sodium level in rabbit synovial fluid

A sensitive and specific high performance liquid chromatography method was established for measuring cefazolin sodium level in rabbit synovial fluid. Acetonitrile was used to precipitate proteins and antipyrine was used as internal standard. Samples were analyzed on a Dionex Ultimate U3000 HPLC system equipped with Phenomenex Luna C18 column （150 mmx4.60 mm, 5 Bm, 100 A）. The mobile phase consisted of acetonitrile and 0.1% formic acid in water. The flow rate was 1 mL/min. The detection wavelength was set at 272 nm. The column temperature was maintained at 25 ℃. The calibration curve was linear in the range of 1.0-100.0 μg/mL （r2 = 0.9999）. The limit of detection （LOD, S/N - 3） was 0.07 μg/mL. The limit of quantitation （LOD, S/N = 10） was 0.22 pg/mL. The recovery of cefazolin sodium （low, medium and high） was 124.6%, 117.8%, and 100.6% （RSD% - 1.9%, 4.0%, 1.1%, n = 5）, respectively. The intra-day and inter-day precision values were in the range of 0.5%-2.7%. The method was simple, sensitive and reliable. It can be used for the quantitative determination of cefazolin sodium in rabbit synovial fluid.

Synovial Fluid C-reactive Protein as a Diagnostic Marker for Periprosthetic Joint Infection： A Systematic Review and Meta-analysis

Background： Periprosthetic joint infection （PJI） is the main cause of failure following total joint arthroplasty. Until now, the diagnosis of PJI is still confronted with technical limitations, and the question of whether synovial fluid biomarker, C-reactive protein （CRP）, can provide high value in the diagnosis of PJl remains unanswered and, therefore, was the aim of the study. Methods： First, we conducted a systematic review on CRP in the diagnosis of PJI by searching online databases using keywords such as ＂periprosthetic joint infection＂, ＂synovial fluid＂, and ＂C-reactive protein＂. Eligible studies providing sufficient data to construct 2 × 2 contingency tables were then selected based on the list of criteria and the quality of included studies was assessed subsequently. Finally, the reported sensitivity, specificity, diagnostic odds ratio （DOR）, summary receiver operating characteristic （SROC） curve, and the area under the SROC （AUSROC） were pooled together and used to evaluate overall diagnostic performance. Results： Seven studies were included in our review, six of which comprising a total of 456 participants were further investigated in our meta-analysis. The pooled sensitivity, specificity, and DOR were 0.92 （95% confidence interval [CI]： 0.86-0.96）, 0.90 （95% CI： 0.87-0.93）, and 101.40 （95% CI： 48.07-213.93）, respectively. The AUSROC was 0.9663 （standard error, 0.0113）. Conclusions： Synovial fluid CRP is a good biomarker for the diagnosis of PJI with high sensitivity and specificity.

Influence of sodium hyaluronate on iNOS expression in synovium and NO content in synovial fluid of rabbits with traumatic osteoarthritis

Objective： To observe the influence of intra-articular injection of sodium hyaluronate （SH） on the expression of inducible nitric oxide synthase （iNOS） in the synovium and nitric oxide （NO） content in synovial fluid of rabbits with traumatic osteoarthritis （OA）. Methods： Sixteen white rabbits underwent unilateral anterior cruciate ligament transection and were randomly divided into 2 groups 5 weeks after the operation. Rabbits in the experimental group received intra-articular injection of 0.3 ml of 1% SH, once a week for 5 weeks. Animals in the control group were treated under the same conditions using physiological saline. All the animals were sacrificed at the 10th week after surgery. The mRNA expression of iNOS in the synovium was analyzed using reverse transcriptionpolymerase chain reaction. The content of NO in the synovial fluid was assayed. Results： The level of iNOS expression of the synovium in the experimental group was lower than that in control group （0.47 ± 0.09 vs. 0.65 ± 0.12, t =3.45, P〈0.01）. Compared with control group, the content of NO decreased significantly in synovial fluid of SH injection group （134.11 μmol/L±12.47 μmol/L vs. 152.17 μmol/L ± 15.69 μmol/L, t =2.55, P〈0.05）. Conclusions： SH significantly decreases the content of NO in the synovial fluid of rabbits with traumatic OA. SH may exert the effect on synovial fluid NO level as a result of the suppression of iNOS expression in the synovium. It may be one of the mechanisms of the therapeutic effect of SH on early traumatic OA.

Diagnostic Value of T-cell Interferon-y Release Assays on Synovial Fluid for Articular Tuberculosis： A Pilot Study

Background： Tuberculosis （TB） remains a major global public health challenge. Articular T/3 is an important form of extrapulmonary tuberculosis, and its diagnosis is difficult because of the low sensitivity of traditional methods. The aim of this study was to analyze the diagnostic value of T-SPOT.TB on synovial fluid for the diagnosis of articular TB. Methods： Patients with suspected articular TB were enrolled consecutively between August 2011 and December 2015. T-SPOT.TB was performed on both synovial fluid mononuclear cells （SFMCs） and peripheral blood mononuclear cells （PBMCs）. The final diagnosis of articular TB was independent of the T-SPOT.TB result. The diagnostic sensitivity, specificity, predictive value, and likelihood ratio of T-SPOT.TB on SFMCs and PBMCs were analyzed. Results： Twenty patients with suspected articular TB were enrolled. Six were diagnosed with articular TB, and 14 patients were diagnosed with other diseases. Sensitivity and specificity were 83% and 86% for T-SPOT.TB on SFMCs, and 67% and 69% for T-SPOT.TB on PBMCs, respectively. The positive predictive value （PPV） and negative predictive value （NPV） of T-SPOT.TB on SFMCs were 71% and 92%, respectively. The PPV and NPV were 50% and 82% for T-SPOT.TB on PBMCs. Conclusion： Sensitivity, specificity, and NPV of T-SPOT.TB on SFMCs appeared higher than that on PBMCs, indicating that T-SPOT. TB on SFMCs might be a rapid and accurate diagnostic test for articular TB.

Influence of synovia constituents on tribological behaviors of articular cartilage

The extremely low friction and minimal wear in natural synovial joints appear to be established by effective lubrication mechanisms based on appropriate combination of articular cartilage and synovial fluid.The complex structure of cartilage composed of collagen and proteoglycan with high water content contributes to high load-carrying capacity as biphasic materials and the various constituents of synovial fluid play important roles in various lubrication mechanisms.However,the detailed differences in functions of the intact and damaged cartilage tissues,and the interaction or synergistic action of synovia constituents with articular cartilage have not yet been clarified.In this study,to examine the roles of synovia constituents and the importance of cartilage surface conditions,the changes in friction were observed in the reciprocating tests of intact and damaged articular cartilage specimens against glass plate lubricated with lubricants containing phospholipid,protein and/or hyaluronic acid as main constituents in synovial fluid.The effectiveness of lubricant constituents and the influence of cartilage surface conditions on friction are discussed.In addition,the protectiveness by synovia constituents for intact articular cartilage surfaces is evaluated.

Clinical and laboratory profile in confirmed vs. suspected septic arthritis patients and its relevance in decision making: A comparative cross-sectional study

Purpose:There were 10%e30%of patients with adult-onset septic arthritis(SA)exhibiting sterile synovial fluid(SF),and the uncertainty in the determining diagnosis of these patients posed a challenge in management.The purpose of this study was to investigate the differences between confirmed(Newman A)and suspected(Newman B&C)SA in adults.Methods:This was a descriptive study with a cross-sectional study design conducted at a tertiary referral centre from July 2016 to February 2019.Patients aged over 18 years presented to the emergency department with clinical features suggestive of SA and were scheduled to undergo arthrotomy and joint lavage by the treating surgeon were included in the study.Patients with prosthetic joint infections and open joint injuries were excluded.Patients’demographic data,clinical features and laboratory parameters were collected.The clinical and laboratory profile(blood and SF)of the adult patients presenting with features suggestive of SA based on Newman criteria was statistically analyzed by SPSS version 20 software and Microsoft Excel.The categorical variables were expressed as proportions while the continuous variables were expressed as mean(SD)or median(IQR)depending upon the normality of distribution.The difference between the two groups for categorical variables was assessed using the Chisquare test and the difference for continuous variables was assessed using the unpaired t-test and the Mann-Whitney test depending upon normality.A p value<0.05 was considered significant.Results:Thirty-six patients were divided into confirmed(n¼19)or suspected(n¼17)SA for assessment based on SF culture.The median(IQR)age of the patients was 50 years(37e60 years).There was no significant difference in demographic,clinical and laboratory parameters between the concerned groups.Eight patients presented with fever.Among the confirmed SA cases,8 were negative for C-reactive protein and 6 had synovial white blood cell count<50,000.Staphylococcus species were isolated in 8 cases.The most common risk factors for SA were chronic kidney disease(25.0%),diabetes mellitus(25.0%),pharmacologic immunosuppression(16.7%),recent joint surgery(11.1%)and distant site infection(11.1%).Conclusion:SA is an orthopaedic emergency that needs prompt and aggressive treatment to prevent catastrophic complications.Confirmed and suspected cases of SA exhibit similar demography,clinical features and laboratory parameters at presentation which may mislead the treating surgeon.Management should be based on sound clinical judgment in the event of failure to culture microorganisms.