Osteoarthritis-Related Degeneration Alters the Biomechanical Properties of Human Menisci Before the Articular Cartilage

An exact understanding of the interplay between the articulating tissues of the knee joint in relation to the osteoarthritis (OA)-related degeneration process is of considerable interest. Therefore, the aim of the present study was to characterize the biomechanical properties of mildly and severely degenerated human knee joints, including their menisci and tibial and femoral articular cartilage (AC) surfaces. A spatial biomechanical mapping of the articulating knee joint surfaces of 12 mildly and 12 severely degenerated human cadaveric knee joints was assessed using a multiaxial mechanical testing machine. To do so, indentation stress relaxation tests were combined with thickness and water content measurements at the lateral and medial menisci and the AC of the tibial plateau and femoral condyles to calculate the instantaneous modulus (IM), relaxation modulus, relaxation percentage, maximum applied force during the indentation, and the water content. With progressing joint degeneration, we found an increase in the lateral and the medial meniscal instantaneous moduli (p < 0.02), relaxation moduli (p < 0.01), and maximum applied forces (p < 0.01), while for the underlying tibial AC, the IM (p = 0.01) and maximum applied force (p < 0.01) decreased only at the medial compartment. Degeneration had no influence on the relaxation percentage of the soft tissues. While the water content of the menisci did not change with progressing degeneration, the severely degenerated tibial AC contained more water (p < 0.04) compared to the mildly degenerated tibial cartilage. The results of this study indicate that degeneration-related (bio-)mechanical changes seem likely to be first detectable in the menisci before the articular knee joint cartilage is affected. Should these findings be further reinforced by structural and imaging analyses, the treatment and diagnostic paradigms of OA might be modified, focusing on the early detection of meniscal degeneration and its respective treatment, with the final aim to delay osteoarthritis onset.

Crosstalk Between Mesenchymal Stromal Cells and Chondrocytes: The Hidden Therapeutic Potential for Cartilage Regeneration

Cartilage injuries following trauma create a puzzling clinical scenario. The finite reparative potential of articular cartilage is well known, and injuries are associated with an increased risk of osteoarthritis. Cell-based therapies have spotlighted chondrocytes and mesenchymal stromal cells (MSCs) as the functional unit of articular cartilage and the progenitor cells, respectively. The available clinical treatments cannot reproduce the biomechanical properties of articular cartilage and call for continuous investigations into alternative approaches. Co-cultures of chondrocytes and MSCs are an attractive in vitro system to step closer to the in vivo multicellular environment's complexity. Research on the mechanisms of interaction between both cell types will reveal essential cues to understand cartilage regeneration. This review describes the latest discoveries on these interactions, along with advantages and main challenges in vitro and in vivo. The successful clinical translation of in vitro studies requires establishing rigorous standards and clinically relevant research models and an organ-targeting therapeutic strategy.

Longitudinal changes in tibial and femoral cartilage thickness are associated with baseline ambulatory kinetics and cartilage oligomeric matrix protein (COMP) measures in an asymptomatic aging population

OBJECTIVE

To address the need for early knee osteoarthritis (OA) markers by testing if longitudinal cartilage thickness changes are associated with specific biomechanical and biological measures acquired at a baseline test in asymptomatic aging subjects.

DESIGN

Thirty-eight asymptomatic subjects over age 45 years were studied at baseline and at an average of 7-9 year follow-up. Gait mechanics and knee MRI were measured at baseline and MRI was obtained at follow-up to assess cartilage thickness changes. A subset of the subjects (n = 12) also had serum cartilage oligomeric matrix protein measured at baseline in response to a mechanical stimulus (30-min walk) (mCOMP). Baseline measures, including the knee extension (KEM), flexion (KFM), adduction (KAM) moments and mCOMP, were tested for associations with cartilage thickness changes in specific regions of the knee.

RESULTS

Cartilage change in the full medial femoral condyle (p = 0.005) and external medial femoral region (p = 0.041) was negatively associated with larger early stance peak KEM. Similarly, cartilage change in the full medial femoral region (p = 0.009) and medial femoral external region (p = 0.043) was negatively associated with larger first peak KAM, while cartilage change in the anterior medial tibia was positively associated with larger first peak KAM (p = 0.003). Cartilage change in the anterior medial tibia was also significantly associated (p = 0.011) with mCOMP levels 5.5-h post-activity (percentage of pre-activity levels).

CONCLUSIONS

Interactions found between gait, mechanically-stimulated serum biomarkers, and cartilage thickness in an at-risk aging asymptomatic population suggest the opportunity for early detection of OA with new approaches that bridge across disciplines and scales.

A Novel Fluorescence Optical Imaging Scoring System for Hand Synovitis in Rheumatoid Arthritis - validity and agreement with ultrasound

OBJECTIVES

To develop and validate a new semiquantitative Fluorescence Optical Imaging (FOI) scoring system - the FOI Enhancement-Generated rheumatoid arthritis (RA) Score (FOIE-GRAS) for synovitis assessment in the hand.

METHODS

The development of FOIE-GRAS was based on consensus of 4 experts in musculoskeletal imaging. Forty-six RA patients, eligible for treatment intensification and with ≥1 clinically swollen joint in the hands and 11 healthy controls were included. FOI, ultrasound and clinical assessment of both hands were obtained at baseline and for RA patients after 3- and 6-months' follow-up. Twenty RA patients had an FOI rescan after 4 hours. Synovitis was scored using FOIE-GRAS and the OMERACT ultrasound synovitis scoring system. All FOI images were scored by 2 readers. Inter-scan, inter-and intra-reader reliability were determined. Furthermore, FOIE-GRAS agreement with ultrasound and responsiveness was assessed.

RESULTS

FOIE-GRAS synovitis was defined as early enhancement and scores based on the degree of coverage of the specific joint region after 3 seconds (0-3). Inter-scan, intra- and inter-reader intraclass correlations coefficients (ICC) were good-excellent for all baseline scores (0.76-0.98) and moderate-to-good for change (0.65-76).The FOIE-GRAS had moderate agreement with ultrasound (ICC 0.30-0.54) for total score, a good standardized response mean (>0.80), and moderate correlation with clinical joint assessment and DAS28-CRP. The median (IQR) reading time per FOI examination was 133 (109;161) seconds. Scores were significantly lower in controls 1(0;4) than RA patients 11(6;19).

CONCLUSION

The FOIE-GRAS offers a feasible and reliable assessment of synovitis in RA, with a moderate correlation with ultrasound and DAS28CRP, and good responsiveness.

Early detection of osteoarthritis in the rat with an antibody specific to type II collagen modified by reactive oxygen species

BACKGROUND

Osteoarthritis (OA) is a disease of the whole joint, with articular cartilage breakdown as a major characteristic. Inflammatory mediators, proteases, and oxidants produced by chondrocytes are known to be responsible for driving cartilage degradation. Nevertheless, the early pathogenic events are still unclear. To investigate this, we employed an antibody that is specific to oxidative post-translationally modified collagen type II (anti-oxPTM-CII) to detect early cartilage pathogenic changes in two rat models of OA.

METHODS

The animals underwent surgery for destabilization of the medial meniscus (DMM) and were sacrificed after 3, 5, 7, 14, and 28 days. Alternatively, anterior cruciate ligament transection with partial meniscectomy (ACLT+pMx) was performed and animals were sacrificed after 1, 3, 5, 7, and 14 days. Joints were stained with toluidine blue and saffron du Gatinais for histological scoring, anti-oxPTM-CII, and anti-collagen type X antibodies (anti-CX).

RESULTS

We observed positive oxPTM-CII staining as early as 1 or 3 days after ACLT+pMx or DMM surgeries, respectively, before overt cartilage lesions were visible. oxPTM-CII was located mostly in the deep zone of the medial tibial cartilage, in the pericellular and territorial matrix of hypertrophic chondrocytes, and co-localized with CX staining. Staining was weak or absent for the lateral compartment or the contralateral knees except at later time points.

CONCLUSION

The results demonstrate that oxidant production and chondrocyte hypertrophy occur very early in the onset of OA, possibly initiating the pathogenic events of OA. We propose to use anti-oxPTM-CII as an early biomarker for OA ahead of radiographic changes.

Are education, exercise and diet interventions a cost-effective treatment to manage hip and knee osteoarthritis? A systematic review

OBJECTIVE

To identify research gaps and inform implementation we systematically reviewed the literature evaluating cost-effectiveness of recommended treatments (education, exercise and diet) for the management of hip and/or knee OA.

METHODS

We searched Medline, Embase, Cochrane Central Register of Controlled Trials, National Health Services Economic Evaluation Database, and EconLit from inception to November 2019 for trial-based economic evaluations investigating hip and/or knee OA core treatments. Two investigators screened relevant publications, extracted data and synthesized results. Risk of bias was assessed using the Consensus on Health Economic Criteria list.

RESULTS

Two cost-minimization, five cost-effectiveness and 16 cost-utility analyses evaluated core treatments in six health systems. Exercise therapy with and without education or diet was cost-effective or cost-saving compared to education or physician-delivered usual care at conventional willingness to pay (WTP) thresholds in 15 out of 16 publications. Exercise interventions were cost-effective compared to physiotherapist-delivered usual care in three studies at conventional WTP thresholds. Education interventions were not cost-effective compared to usual care or placebo at conventional WTP thresholds in three out of four publications.

CONCLUSIONS

Structured core treatment programs were clinically effective and cost-effective, compared to physician-delivered usual care, in five health care systems. Providing education about core treatments was not consistently cost-effective. Implementing structured core treatment programs into funded clinical pathways would likely be an efficient use of health system resources and enhance physician-delivered usual primary care.

Influence of the physical activity in the elderly people diagnosed with knee osteoarthritis during the pandemic period caused by COVID-19

Introduction. Knee osteoarthritis is considered to be a chronic disease that affects the joints by causing pain, joint stiffness and decreased functional capacity. Regular physical activity can keep and increase functional capacity, it can reduce pain by improving movement behavior. The disruption of the sedentary behavior of the elderly patients with knee osteoarthritis can lead to improved physical function and general health. The purpose of this paper is to point out the role of physical activity in the elderly people diagnosed with knee osteoarthritis during the COVID-19 pandemic. Material and method. A total of 155 patients diagnosed (clinical and imaging) with knee ostoarthritis, who were treated on an outpatient basis, from May to September 2020, were studied. The parameters assessed in the study were pain, joint stiffness, the ability to carry out daily activities, anxiety and quality of life. Results and discussion.The studied group of patients was homogeneous in terms of the weight by age group and gender. Higher values were recorded in the study group in the evaluation of patients based on scales, the results being statistically significant, with value for p<0.05, which means that the hypothesis was validated. Conclusions. Patients of the study group recorded improvementin of functional capacity, joint stability and static and dynamic balance, which allowed a faster reintegration into the family and society. Keywords: physical activity, pain, elderly people, knee osteoarthritis,

Joint hypermobility and its association with self-reported knee health: A cross-sectional study of healthy Australian adults

AIM

The primary aim of this study was to determine the association between generalized joint hypermobility (GJH), knee-specific hypermobility (KSH) and self-reported knee health in an Australian population. Secondary aims included elucidating ethnic/gender differences in GJH/KSH prevalence and knee health, and identifying KSH using a novel knee extension range of motion cut-off method.

METHOD

Knee extension range, Beighton score, and 5 domains of the Knee Injury and Osteoarthritis Outcome Score (KOOS) were collected from adults aged 18-101 years self-identifying as healthy, and were grouped by ethnicity and gender. Two established Beighton score criteria and 1 novel knee extension range cut-off method were used to determine GJH and KSH respectively. Point-biserial correlation tested the associations between GJH/KSH and KOOS. Differences in GJH/KSH prevalence and knee health between ethnic/gender groups were determined with the Chi-squared test.

RESULTS

Of 732 participants (50% male), 80.3% were Caucasian. No correlations were found between GJH and KOOS while a very weak correlation was found between KSH and 1 KOOS domain (r > -.30; P = .04). Prevalence of GJH was higher in non-Caucasians (17.4% vs 5.6%, P < .001) and females (4.4% vs 1.1%, P = .007). Prevalence of KSH between ethnic and gender groups was not significantly different (P = .50 and P = .69 respectively). Non-Caucasians scored higher (better) in all KOOS domains than Caucasians (all P < .05).

CONCLUSION

Those who met the age- and gender-specific criteria for GJH/KSH did not report worse knee health than their non-hypermobile counterparts. Clinicians can assure individuals who exhibit GJH/KSH that these are not associated with lower knee health and function.

Exploring views of orthopaedic surgeons, rheumatologists and general practitioners about osteoarthritis management

BACKGROUND

Delivery of recommended treatments for hip and knee osteoarthritis (OA) is known to be discordant with guideline recommendations. However, professional views related to OA management across medical and surgical disciplines are not well understood. The aim of this study was to explore the views of medical professionals about management of hip and knee OA.

METHODS

Qualitative study. Semistructured individual interviews were conducted with orthopaedic surgeons, rheumatologists and general practitioners routinely involved in the management of OA. Interviews were audiotaped, transcribed, member-checked, coded and thematically analysed.

RESULTS

Fifteen medical professionals were interviewed. Three main themes were: (i) recognition of the importance of nonsurgical management of hip and knee OA, focussed on self-management, exercise-therapy, weight management and analgesia; (ii) joint replacement being considered the 'last resort' for end stage disease not responding to nonsurgical management; and (iii) determination of management 'success' through patient perceptions was more common than the use of validated instruments. Views on management broadly converged across disciplines, except for the role of joint replacement, considered an adjunct in the overall management of OA by rheumatologists and as a definitive cure by orthopaedic surgeons.

CONCLUSIONS

Aligning with current guidelines, medical professionals recognised the importance of nonsurgical management focussed on exercise-therapy for hip and knee OA, and concurred that joint replacement surgery should be a last resort. A focus on patient education was less prominent, which along with implementation of validated outcome measures in routine medical practice, may require greater health system support.

The effects of sprifermin on symptoms and structure in a subgroup at risk of progression in the FORWARD knee osteoarthritis trial

OBJECTIVE

To assess pain outcomes and cartilage thickness change in a subgroup at risk (SAR) of further progression in the FORWARD trial of knee osteoarthritis patients treated with sprifermin.

METHODS

Patients were randomised 1:1:1:1:1 to: sprifermin 100 µg every 6 months (q6mo), 100 µg q12mo, 30 µg q6mo, 30 µg q12mo, or placebo for 18 months. SAR was defined as baseline medial or lateral minimum joint-space width (mJSW) 1.5-3.5 mm and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain score 40-90 units. Follow-up to 3 years was included in the analysis. Treatment benefit was explored by repeated measures, linear dose-effect trends by timepoint.

RESULTS

The SAR comprised 161 (29%) of 549 patients. Mean difference (95% CI) in WOMAC pain at year 3 for sprifermin 100 µg q6mo vs placebo SAR was -8.75 (-22.42, 4.92) for SAR vs 0.97 (-6.22, 8.16) for the intent-to-treat population. SAR placebo patients lost more cartilage over 2 years than the modified ITT (mITT) placebo arm (mean change from baseline, mm [SD]: -0.05 [0.10] vs -0.02 [0.07]). Net total femorotibial joint thickness gain with sprifermin 100 µg q6mo (adjusted mean difference from placebo [95% CI] was similar in the SAR and in the mITT group: 0.06 [0.01, 0.11] vs 0.05 [0.03, 0.07]).

CONCLUSIONS

Selection for low mJSW and moderate-to-high pain at baseline resulted in more rapid disease progression and demonstrated translation of structure modification (with maintained net benefit on total cartilage thickness) into symptomatic benefit. This subgroup may represent a target population for future trials.

CLINICAL TRIAL REGISTRATION

NCT01919164.

Hypoxia and Hypoxia-Inducible Factor-1α Regulate Endoplasmic Reticulum Stress in Nucleus Pulposus Cells: Implications of Endoplasmic Reticulum Stress for Extracellular Matrix Secretion

Endoplasmic reticulum (ER) stress is shown to promote nucleus pulposus (NP) cell apoptosis and intervertebral disc degeneration. However, little is known about ER stress regulation by the hypoxic disc microenvironment and its contribution to extracellular matrix homeostasis. NP cells were cultured under hypoxia (1% partial pressure of oxygen) to assess ER stress status, and gain-of-function and loss-of-function approaches were used to assess the role of hypoxia-inducible factor (HIF)-1α in this pathway. In addition, the contribution of ER stress induction on the NP cell secretome was assessed by a nontargeted quantitative proteomic analysis by sequential windowed data independent acquisition of the total high-resolution mass spectra-mass spectrometry. NP cells exhibited a lower ER stress burden under hypoxia. Knockdown of HIF-1α increased C/EBP homologous protein, protein kinase RNA-like endoplasmic reticulum kinase (PERK), and activating transcription factor 6 (ATF6) levels, whereas HIF-1α stabilization decreased the expression of ER stress markers Ddit3, Hsp5a, Atf6, and Eif2a. Interestingly, ER stress inducers tunicamycin and thapsigargin induced HIF-1α activity under hypoxia while promoting the unfolded protein response. NP cell secretome analysis demonstrated an impact of ER stress induction on extracellular matrix secretion, with decreases in collagens and cell adhesion-related proteins. Moreover, analysis of transcriptomic data of NP tissues from aged mice and degenerated human discs showed higher levels of unfolded protein response markers and decreased levels of matrix components. Our study shows, for the first time, that hypoxia and HIF-1α attenuate ER stress responses in NP cells, and ER stress promotes inefficient extracellular matrix secretion under hypoxia.

Identifying Robust Risk Factors for Knee Osteoarthritis Progression: An Evolutionary Machine Learning Approach

Knee osteoarthritis (KOA) is a multifactorial disease which is responsible for more than 80% of the osteoarthritis disease's total burden. KOA is heterogeneous in terms of rates of progression with several different phenotypes and a large number of risk factors, which often interact with each other. A number of modifiable and non-modifiable systemic and mechanical parameters along with comorbidities as well as pain-related factors contribute to the development of KOA. Although models exist to predict the onset of the disease or discriminate between asymptotic and OA patients, there are just a few studies in the recent literature that focused on the identification of risk factors associated with KOA progression. This paper contributes to the identification of risk factors for KOA progression via a robust feature selection (FS) methodology that overcomes two crucial challenges: (i) the observed high dimensionality and heterogeneity of the available data that are obtained from the Osteoarthritis Initiative (OAI) database and (ii) a severe class imbalance problem posed by the fact that the KOA progressors class is significantly smaller than the non-progressors' class. The proposed feature selection methodology relies on a combination of evolutionary algorithms and machine learning (ML) models, leading to the selection of a relatively small feature subset of 35 risk factors that generalizes well on the whole dataset (mean accuracy of 71.25%). We investigated the effectiveness of the proposed approach in a comparative analysis with well-known FS techniques with respect to metrics related to both prediction accuracy and generalization capability. The impact of the selected risk factors on the prediction output was further investigated using SHapley Additive exPlanations (SHAP). The proposed FS methodology may contribute to the development of new, efficient risk stratification strategies and identification of risk phenotypes of each KOA patient to enable appropriate interventions.

Quantitative Proteomics Reveals Changes Induced by TIMP-3 on Cell Membrane Composition and Novel Metalloprotease Substrates

Ectodomain shedding is a key mechanism of several biological processes, including cell-communication. Disintegrin and metalloproteinases (ADAMs), together with the membrane-type matrix metalloproteinases, play a pivotal role in shedding transmembrane proteins. Aberrant shedding is associated to several pathological conditions, including arthritis. Tissue inhibitor of metalloproteases 3 (TIMP-3), an endogenous inhibitor of ADAMs and matrix metalloproteases (MMPs), has been proven to be beneficial in such diseases. Thus, strategies to increase TIMP-3 bioavailability in the tissue have been sought for development of therapeutics. Nevertheless, high levels of TIMP-3 may lead to mechanism-based side-effects, as its overall effects on cell behavior are still unknown. In this study, we used a high-resolution mass-spectrometry-based workflow to analyze alterations induced by sustained expression of TIMP-3 in the cell surfaceome. In agreement with its multifunctional properties, TIMP-3 induced changes on the protein composition of the cell surface. We found that TIMP-3 had differential effects on metalloproteinase substrates, with several that accumulated in TIMP-3-overexpressing cells. In addition, our study identified potentially novel ADAM substrates, including ADAM15, whose levels at the cell surface are regulated by the inhibitor. In conclusion, our study reveals that high levels of TIMP-3 induce modifications in the cell surfaceome and identifies molecular pathways that can be deregulated via TIMP-3-based therapies.

Prediction of Joint Space Narrowing Progression in Knee Osteoarthritis Patients

Osteoarthritis is a joint disease that commonly occurs in the knee (KOA). The continuous increase in medical data regarding KOA has triggered researchers to incorporate artificial intelligence analytics for KOA prognosis or treatment. In this study, two approaches are presented to predict the progression of knee joint space narrowing (JSN) in each knee and in both knees combined. A machine learning approach is proposed with the use of multidisciplinary data from the osteoarthritis initiative database. The proposed methodology employs: (i) A clustering process to identify groups of people with progressing and non-progressing JSN; (ii) a robust feature selection (FS) process consisting of filter, wrapper, and embedded techniques that identifies the most informative risk factors; (iii) a decision making process based on the evaluation and comparison of various classification algorithms towards the selection and development of the final predictive model for JSN; and (iv) post-hoc interpretation of the features' impact on the best performing model. The results showed that bounding the JSN progression of both knees can result to more robust prediction models with a higher accuracy (83.3%) and with fewer risk factors (29) compared to the right knee (77.7%, 88 risk factors) and the left knee (78.3%, 164 risk factors), separately.

Significant Changes in Serum MicroRNAs after High Tibial Osteotomy in Medial Compartmental Knee Osteoarthritis: Potential Prognostic Biomarkers

High tibial osteotomy (HTO) is an effective alternative for medial compartmental knee osteoarthritis (OA). Circulating microRNAs (miRNAs) are known to serve as OA-related biomarkers. The present study investigated the differential expression of serum miRNAs before and after HTO to identify potential miRNAs as prognostic biomarkers. miRNA-polymerase chain reaction (PCR) arrays were used to screen for miRNAs in the serum at preoperative and 6-month postoperative time points from six patients, and the differentially expressed miRNAs identified in the profiling stage were validated using real-time PCR at post-operative months 6 and 18 in 27 other HTO-treated patients. Among 84 miRNAs involved in the inflammatory process, three (miR-19b-3p, miR-29c-3p, and miR-424-5p) showed differential expression patterns in the profiling stage (p = 0.011, 0.015, and 0.021, respectively). Levels of these three and four other miRNAs (miR-140-3p, miR-454-3p, miR-let-7e-5p, and miR-885-5p) known to be related to OA progression were evaluated in the serum of 27 patients. Only four miRNAs (miR-19b-3p, miR-140-3p, miR-454-3p, and miR-let-7e-5p) were significantly upregulated at postoperative month 6 (p = 0.003, 0.005, 0.004, and 0.004, respectively), and only miR-140-3p was significantly upregulated up to 18 months after operation (p = 0.003). Together, this study reveals the significantly upregulated serum miRNAs after HTO as potential prognostic biomarkers; however, further studies are warranted to elucidate their clinical implications.

Osteoarthritis year in review 2020: imaging

This narrative "Year in Review" highlights a selection of articles published between January 2019 and April 2020, to be presented at the OARSI World Congress 2020 within the field of osteoarthritis (OA) imaging. Articles were obtained from a PubMed search covering the above period, utilizing a variety of relevant search terms. We then selected original and review studies on OA-related imaging in humans, particularly those with direct clinical relevance, with a focus on the knee. Topics selected encompassed clinically relevant models of early OA, particularly imaging applications on cruciate ligament rupture, as these are of direct clinical interest and provide potential opportunity to evaluate preventive therapy. Further, imaging applications on structural modification of articular tissues in patients with established OA, by non-pharmacological, pharmacological and surgical interventions are summarized. Finally, novel deep learning approaches to imaging are reviewed, as these facilitate implementation and scaling of quantitative imaging application in clinical trials and clinical practice. Methodological or observational studies outside these key focus areas were not included. Studies focused on biology, biomechanics, biomarkers, genetics and epigenetics, and clinical studies that did not contain an imaging component are covered in other articles within the OARSI "Year in Review" series. In conclusion, exciting progress has been made in clinically validating human models of early OA, and the field of automated articular tissue segmentation. Most importantly though, it has been shown that structure modification of articular cartilage is possible, and future research should focus on the translation of these structural findings to clinical benefit.

Current Models for Development of Disease-Modifying Osteoarthritis Drugs

Osteoarthritis (OA) is a painful and disabling disease that affects millions of people worldwide. Symptom-alleviating treatments exist, although none with long-term efficacy. Furthermore, there are currently no disease-modifying OA drugs (DMOADs) with demonstrated efficacy in OA patients, which is, in part, attributed to a lack of full understanding of the pathogenesis of OA. The inability to translate findings from basic research to clinical applications also highlights the deficiencies in the available OA models at simulating the clinically relevant pathologies and responses to treatments in humans. In this review, the current status in the development of DMOADs will be first presented, with special attention to those in Phase II-IV clinical trials. Next, current in vitro, ex vivo, and in vivo OA models are summarized and the respective advantages and disadvantages of each are highlighted. Of note, the development and application of microphysiological or tissue-on-a-chip systems for modeling OA in humans are presented and the issues that need to be addressed in the future are discussed. Microphysiological systems should be given serious consideration for their inclusion in the DMOAD development pipeline, both for their ability to predict drug safety and efficacy in human clinical trials at present, as well as for their potential to serve as a test platform for personalized medicine. Impact statement At present, no disease-modifying osteoarthritis (OA) drugs (DMOADs) have been approved for widespread clinical use by regulatory bodies. The failure of developing effective DMOADs is likely owing to multiple factors, not the least of which are the intrinsic differences between the intact human knee joint and the preclinical models. This work summarizes the current OA models for the development of DMOADs, discusses the advantages/disadvantages of each, and then proposes future model development to aid in the discovery of effective and personalized DMOADs. The review also highlights the microphysiological systems, which are emerging as a new platform for drug development.

Associations between Fluorescence Optical Imaging and Magnetic Resonance Imaging and symptoms in hand osteoarthritis

OBJECTIVES

To investigate whether Fluorescence Optical Imaging (FOI) enhancement and Magnetic Resonance Imaging (MRI)-defined synovitis are associated with pain and physical function in hand osteoarthritis (OA) patients.

METHODS

Bilateral FOI scans and MRI of the dominant hand were available for 221 patients. Finger joints were examined for tenderness on palpation. Pain in individual finger joints during the last 24 h and last 6 weeks and hand pain intensity by the Australian/Canadian hand index and Numeric Rating Scale were self-reported. On joint level, we applied logistic regression with generalized estimating equations to examine whether FOI enhancement and MRI-defined synovitis were associated with pain in the same joint. On subject level, we applied linear regression to assess whether FOI and MRI sum scores were associated with pain intensity and physical function.

RESULTS

Metacarpophalangeal and thumb base joints were excluded from analyses due to little/no FOI enhancement. Finger joints with FOI enhancement on the composite image had higher odds (95% confidence interval) of pain during the last 6 weeks (grade 1: 1.4 (1.2-1.6), grade 2-3: 2.1 (1.7-2.6)). Similar results were found for joint pain during the last 24 h and joint tenderness in fingers. Numerically stronger associations were found between MRI-defined synovitis and finger joint pain/tenderness. FOI and MRI sum scores demonstrated no/weak associations with hand pain and physical function.

CONCLUSION

FOI enhancement and MRI-defined synovitis were associated with pain in the same finger joint. None of the imaging modalities demonstrated consistent associations with pain, stiffness and physical function on subject level.

Autonomous spheroid formation by culture plate compartmentation

Scaffold-free 3D cell cultures (e.g. pellet cultures) are widely used in medical science, including cartilage regeneration. Their drawbacks are high time/reagent consumption and lack of early readout parameters. While optimisation was achieved by automation or simplified spheroid generation, most culture systems remain expensive or require tedious procedures. The aim of this study was to establish a system for resource efficient spheroid generation. This was achieved by compartmentation of cell culture surfaces utilising laser engraving (grid plates). This compartmentation triggered autonomous spheroid formation via rolling-up of the cell monolayer in human adipose-derived stem cells (ASC/TERT1) and human articular chondrocytes (hAC)-ASC/TERT1 co-cultures, when cultivated on grid plates under chondrogenic conditions. Plates with 3 mm grid size yielded stable diameters (about 300 μm). ASC/TERT1 spheroids fully formed within 3 weeks while co-cultures took 1-2 weeks, forming significantly faster with increasing hAC ratio (p<0.05 and 0.01 for 1:1 and 1:4 ASC/TERT1:hAC ratio respectively). Co-cultures showed slightly lower spheroid diameter, due to earlier spheroid formation and incomplete monolayer formation. However, this was associated with more regular matrix distribution in the co-culture. Both showed differentiation capacity comparable to standard pellet culture in (immune-)histochemistry and RT-qPCR. To assess usability for cartilage repair, spheroids were embedded into a hydrogel (fibrin), yielding cellular outgrowth and matrix deposition, which was especially pronounced in co-cultures. The herein presented novel cell culture system is not only a promising tool for autonomous spheroid generation with the potential of experimental and clinical application in tissue engineering but also for high-throughput analysis for both pharmaceutical and therapeutic uses.

Analyzing Femorotibial Cartilage Thickness Using Anatomically Standardized Maps: Reproducibility and Reference Data

Alterations in cartilage thickness (CTh) are a hallmark of knee osteoarthritis, which remain difficult to characterize at high resolution, even with modern magnetic resonance imaging (MRI), due to a paucity of standardization tools. This study aimed to assess a computational anatomy method producing standardized two-dimensional femorotibial CTh maps. The method was assessed with twenty knees, processed following three common experimental scenarios. Cartilage thickness maps were obtained for the femorotibial cartilages by reconstructing bone and cartilage mesh models in tree-dimension, calculating three-dimensional CTh maps, and anatomically standardizing the maps. The intra-operator accuracy (median (interquartile range, IQR) of -0.006 (0.045) mm), precision (0.152 (0.070) mm), entropy (7.02 (0.71) and agreement (0.975 (0.020))) results suggested that the method is adequate to capture the spatial variations in CTh and compare knees at varying osteoarthritis stages. The lower inter-operator precision (0.496 (0.132) mm) and agreement (0.808 (0.108)) indicate a possible loss of sensitivity to detect differences in a setting with multiple operators. The results confirmed the promising potential of anatomically standardized maps, with the lower inter-operator reproducibility stressing the need to coordinate operators. This study also provided essential reference data and indications for future research using CTh maps.

Bone Structure Analysis of the Radius Using Ultrahigh Field (7T) MRI: Relevance of Technical Parameters and Comparison with 3T MRI and Radiography

Bone fractal signature analysis (FSA-also termed bone texture analysis) is a tool that assesses structural changes that may relate to clinical outcomes and functions. Our aim was to compare bone texture analysis of the distal radius in patients and volunteers using radiography and 3T and 7T magnetic resonance imaging (MRI)-a patient group (n = 25) and a volunteer group (n = 25) were included. Participants in the patient group had a history of chronic wrist pain with suspected or confirmed osteoarthritis and/or ligament instability. All participants had 3T and 7T MRI including T1-weighted turbo spin echo (TSE) sequences. The 7T MRI examination included an additional high-resolution (HR) T1 TSE sequence. Radiographs of the wrist were acquired for the patient group. When comparing patients and volunteers (unadjusted for gender and age), we found a statistically significant difference of horizontal and vertical fractal dimensions (FDs) using 7T T1 TSE-HR images in low-resolution mode (horizontal: p = 0.04, vertical: p = 0.01). When comparing radiography to the different MRI sequences, we found a statistically significant difference for low- and high-resolution horizontal FDs between radiography and 3T T1 TSE and 7T T1 TSE-HR. Vertical FDs were significantly different only between radiographs and 3T T1 TSE in the high-resolution mode; FSA measures obtained from 3T and 7T MRI are highly dependent on the sequence and reconstruction resolution used, and thus are not easily comparable between MRI systems and applied sequences.

Low-dose radiotherapy (LD-RT) for COVID-19-induced pneumopathy: a worth considering approach

PURPOSE

It seems that 2020 would be always remembered by the name of novel coronavirus (designated as SARS-CoV-2), which exerted its deteriorating effects on the health care, economy, education, and political relationships. In August 2020 more than eight hundred thousand patients lost their lives due to acute respiratory syndrome. In the limited list of therapeutic approaches, the effectiveness of low-dose radiation therapy (LD-RT) for curing inflammatory-related diseases have sparkled a light that probably this approach would bring promising advantages for COVID-19 patients. LD-RT owns its reputation from its ability to modulate the host inflammatory responses by blocking the production of pro-inflammatory cytokines and hampering the activity of leukocytes. Moreover, the cost-effective and availability of this method allow it to be applied to a large number of patients, especially those who could not receive anti-IL-6 treatments in low-income countries. But enthusiasm for applying LD-RT for the treatment of COVID-19 patients has been muted yet.

CONCLUSION

In this review, we take a look at LD-RT mechanisms of action in the treatment of nonmalignant diseases, and then through studying both the dark and bright sides of this approach, we provide a thorough discussion if LD-RT might be a promising therapeutic approach in COVID-19 patients.

Mesenchymal Stromal Cell-Derived Extracellular Vesicles - Silver Linings for Cartilage Regeneration?

As the world's population is aging, the incidence of the degenerative disease Osteoarthritis (OA) is increasing. Current treatment options of OA focus on the alleviation of the symptoms including pain and inflammation rather than on restoration of the articular cartilage. Cell-based therapies including the application of mesenchymal stromal cells (MSCs) have been a promising tool for cartilage regeneration approaches. Due to their immunomodulatory properties, their differentiation potential into cells of the mesodermal lineage as well as the plurality of sources from which they can be isolated, MSCs have been applied in a vast number of studies focusing on the establishment of new treatment options for Osteoarthritis. Despite promising outcomes in vitro and in vivo, applications of MSCs are connected with teratoma formation, limited lifespan of differentiated cells as well as rejection of the cells after transplantation, highlighting the need for new cell free approaches harboring the beneficial properties of MSCs. It has been demonstrated that the regenerative potential of MSCs is mediated by the release of paracrine factors rather than by differentiation into cells of the desired tissue. Besides soluble factors, extracellular vesicles are the major component of a cell's secretome. They represent novel mechanisms by which (pathogenic) signals can be communicated between cell types as they deliver bioactive molecules (nucleic acids, proteins, lipids) from the cell of origin to the target cell leading to specific biological processes upon uptake. This review will give an overview about extracellular vesicles including general characteristics, isolation methods and characterization approaches. Furthermore, the role of MSC-derived extracellular vesicles in in vitro and in vivo studies for cartilage regeneration will be summarized with special focus on transported miRNA which either favored the progression of OA or protected the cartilage from degradation. In addition, studies will be reviewed investigating the impact of MSC-derived extracellular vesicles on inflammatory arthritis. As extracellular vesicles are present in all body fluids, their application as potential biomarkers for OA will also be discussed in this review. Finally, studies exploring the combination of MSC-derived extracellular vesicles with biomaterials for tissue engineering approaches are summarized.

Sex- and injury-based differences in knee biomechanics in mouse models of post-traumatic osteoarthritis

Sex and joint injury are risk factors implicated in the onset and progression of osteoarthritis (OA). In mouse models of post-traumatic OA (ptOA), the pathogenesis of disease is notably impacted by sex (often worse in males) and injury model (e.g. meniscal versus ligament injury). Increasing ptOA progression and severity is often associated with greater relative instability of the joint but few studies have directly quantified changes in joint mechanics after injury and compared outcomes across multiple models in both male and female mice. Passive anterior-posterior knee biomechanics were evaluated in 10-week-old, male and female C57BL/6J mice. PtOA injury models included destabilisation of the medial meniscus (DMM), anterior cruciate ligament transection (ACLT) or mechanical rupture (ACLR), and combined DMM and ACLT (DMM + ACLT). Sham operated and non-operated controls (NOC) were included for baseline comparisons. The test apparatus loaded hindlimbs at 60° flexion between ± 1 N at 0.5 mm/s (build specifications available for download: https://doi.org/10.17632/z754455x3c.1). Measures of joint laxity (range of motion, neutral zone) and stiffness were calculated. Joint laxity was comparable between male and female mice while joint stiffness was greater in females (P ≤ 0.002, correcting for body-mass and injury-model). Anterior-posterior joint mechanics were minimally altered by DMM but significantly affected by loss of the ACL (P < 0.001), with equivalent changes between ACL-injury models despite different injury mechanisms and adjacent meniscal damage. These findings suggest that despite the important role of joint injury; sex- and model-specific differences in ptOA progression and severity are not primarily driven by altered anterior-posterior knee biomechanics.

Macrophage Activation in the Synovium of Healthy and Osteoarthritic Equine Joints

Synovitis is a major component of osteoarthritis and is driven primarily by macrophages. Synovial macrophages are crucial for joint homeostasis (M2-like phenotype), but induce inflammation (M1-like) when regulatory functions become overwhelmed. Macrophage phenotypes in synovium from osteoarthritic and healthy joints are poorly characterized; however, comparative knowledge of their phenotypes during health and disease is paramount for developing targeted treatments. This study compared patterns of macrophage activation in healthy and osteoarthritic equine synovium and correlated histology with cytokine/chemokine profiles in synovial fluid. Synovial histology and immunohistochemistry for M1-like (CD86), M2-like (CD206, IL-10), and pan macrophage (CD14) markers were performed on biopsies from 29 healthy and 26 osteoarthritic equine joints. Synovial fluid cytokines (MCP-1, IL-10, PGE2, IL-1β, IL-6, TNF-α, IL-1ra) and growth factors (GM-CSF, SDF-1α+β, IGF-1, and FGF-2) were quantified. Macrophage phenotypes were not as clearly defined in vivo as they are in vitro. All macrophage markers were expressed with minimal differences between OA and normal joints. Expression for all markers increased proportionate to synovial inflammation, especially CD86. Synovial fluid MCP-1 was higher in osteoarthritic joints while SDF-1 and IL-10 were lower, and PGE2 concentrations did not differ between groups. Increased CD14/CD86/CD206/IL-10 expression was associated with synovial hyperplasia, consistent with macrophage recruitment and activation in response to injury. Lower synovial fluid IL-10 could suggest that homeostatic mechanisms from synovial macrophages became overwhelmed preventing inflammation resolution, resulting in chronic inflammation and OA. Further investigations into mechanisms of arthritis resolution are warranted. Developing pro-resolving therapies may provide superior results in the treatment of OA.

Exploring the Association of Innate Immunity Biomarkers With MRI Features in Both Early and Late Stages Osteoarthritis

Objective: To evaluate the association between biomarkers of innate immunity and the magnetic resonance imaging (MRI) features of earlier and later stages of knee osteoarthritis (KOA). Methods: From 139 and 20 participants with earlier and later stages of KOA, respectively, we analyzed knee MRIs scored using the Boston Leeds Osteoarthritis Knee Score (BLOKS) at recruitment with biomarkers. In paired serum (s) and synovial fluid (sf), we quantified three biomarkers related to innate immunity: lipopolysaccharide binding protein (LBP), CD14 and Toll-like receptor 4 (TLR4), and three proinflammatory biomarkers [interleukin-6 (IL6), IL8, and tumor necrosis factor alpha (TNFα)]. Results: In participants with earlier KOA, (s) LBP was statistically significantly associated with meniscal extrusion, and (sf) CD14 was associated with effusion after adjustment with age, sex, and body mass index. In participants with later stage of KOA, (sf) LBP was associated with effusion. (sf) CD14 was associated with cartilage loss and BML. In earlier stage of KOA, the proinflammatory biomarkers IL6, IL8, and TNFα were associated with most MRI features. Conclusion: Innate immunity biomarkers (s) LBP was associated with MRI meniscal extrusion; (sf) CD14 was associated with MRI synovial inflammation in earlier stage and BMLs in later stage of KOA. Associations between proinflammatory biomarkers and various MRI features in earlier stage of KOA were observed.

A patients' view of OA: the Global Osteoarthritis Patient Perception Survey (GOAPPS), a pilot study

BACKGROUND

Globally, osteoarthritis (OA) is the third condition associated with disability. There is still poor treatment in OA but science holds the key to finding better treatments and a cure. It is essential to learn what's important to patients from them to implement the most effective OA management. The OA Patients Task Force, conducted the Global OA Patient Perception Survey (GOAPPS)-the first global survey made by patients to analize the quality of life (QoL) & patient perceptions of care. The goal was to collect data on OA patients' perception of OA to understand patients' needs and expectations to improve OA management.

METHODS

Observational, cross-sectional study by online survey data collection from six countries, translated into three languages. The questionnaire was comprised of 3 sections: patient demographics and clinical symptomology characteristics; relationship with physicians: perception of attention, treatment, and information provided; and OA impact on daily activity and QoL. The results of the survey were evaluated using the Limited Data Set. The survey results were analyzed using descriptive statistics to characterize the patients' answers. Additionally, Cronbach's alpha was calculated to determine internal consistency validity.

RESULTS

A total of 1512 surveys were completed in 6 countries. 84.2% of respondents reported pain/tenderness and 91.1% experienced limitations to physical activities. 42.3% of patients were not satisfied with their current OA treatment. 86% had comorbidities, especially hypertension, and obesity. 51.3 and 78% would like access to additional drug or additional non-drug/non-surgical treatments respectively. 48.2% of patients perceived their QoL to be affected by OA. The Cronbach's alpha was 0.61.

CONCLUSIONS

OA has a significant impact on patients' daily activities and their desire to play an active role in managing this disease. Patients are seeking additional treatments, especially no pharmacological/no surgical treatments stressing the need for investing in clinical research, implementing OA preventive measures, and managing interventions to improve the healthcare value chain in OA.

Emerging Technologies and Platforms for the Immunodetection of Multiple Biochemical Markers in Osteoarthritis Research and Therapy

Biomarkers, especially biochemical markers, are important in osteoarthritis (OA) research, clinical trials, and drug development and have potential for more extensive use in therapeutic monitoring. However, they have not yet had any significant impact on disease diagnosis and follow-up in a clinical context. Nevertheless, the development of immunoassays for the detection and measurement of biochemical markers in OA research and therapy is an active area of research and development. The evaluation of biochemical markers representing low-grade inflammation or extracellular matrix turnover may permit OA prognosis and expedite the development of personalized treatment tailored to fit particular disease severities. However, currently detection methods have failed to overcome specific hurdles such as low biochemical marker concentrations, patient-specific variation, and limited utility of single biochemical markers for definitive characterization of disease status. These challenges require new and innovative approaches for development of detection and quantification systems that incorporate clinically relevant biochemical marker panels. Emerging platforms and technologies that are already on the way to implementation in routine diagnostics and monitoring of other diseases could potentially serve as good technological and strategic examples for better assessment of OA. State-of-the-art technologies such as advanced multiplex assays, enhanced immunoassays, and biosensors ensure simultaneous screening of a range of biochemical marker targets, the expansion of detection limits, low costs, and rapid analysis. This paper explores the implementation of such technologies in OA research and therapy. Application of novel immunoassay-based technologies may shed light on poorly understood mechanisms in disease pathogenesis and lead to the development of clinically relevant biochemical marker panels. More sensitive and specific biochemical marker immunodetection will complement imaging biomarkers and ensure evidence-based comparisons of intervention efficacy. We discuss the challenges hindering the development, testing, and implementation of new OA biochemical marker assays utilizing emerging multiplexing technologies and biosensors.

Biological strategies for osteoarthritis: from early diagnosis to treatment

PURPOSE

To provide an updated review of the literature on the use of orthobiologics as a potential treatment option to alleviate symptoms associated with osteoarthritis (OA), slow the progression of the disease, and aid in cartilage regeneration.

METHODS

A comprehensive review of the literature was performed to identify basic science and clinical studies examining the role of orthobiologics in the diagnosis and management of osteoarthritis.

RESULTS

Certain molecules (such as interleukin-6 (IL-6), interleukin-8 (IL-8), matrix metalloproteinase (MMPs), cartilage oligomeric matrix protein (COMP), and tumor necrosis factor (TNF), microRNAs, growth differentiation factor 11 (GDF-11)) have been recognized as biomarkers that are implicated in the pathogenesis and progression of degenerative joint disease (DJD). These biomarkers have been used to develop newer diagnostic applications and targeted biologic therapies for DJD. Local injection therapy with biologic agents such as platelet-rich plasma or stem cell-based preparations has been associated with significant improvement in joint pain and function in patients with OA and has increased in popularity during the last decade. The combination of PRP with kartogenin or TGF-b3 may also enhance its biologic effect. The mesenchymal stem cell secretome has been recognized as a potential target for the development of OA therapies due to its role in mediating the chondroprotective effects of these cells. Recent experiments have also suggested the modification of gut microbiome as a newer method to prevent OA or alter the progression of the disease.

CONCLUSIONS

The application of orthobiologics for the diagnosis and treatment of DJD is a rapidly evolving field that will continue to expand. The identification of OA-specific and joint-specific biomarker molecules for early diagnosis of OA would be extremely useful for the development of preventive and therapeutic protocols. Local injection therapies with HA, PRP, BMAC, and other stem cell-based preparations are currently being used to improve pain and function in patients with early OA or those with progressed disease who are not surgical candidates. Although the clinical outcomes of these therapies seem to be promising in clinical studies, future research will determine the true role of orthobiologic applications in the field of DJS.

Implementing models of care for musculoskeletal conditions in health systems to support value-based care

Models of Care (MoCs), and their local Models of Service Delivery, for people with musculoskeletal conditions are becoming an acceptable way of supporting effective implementation of value-based care. MoCs can support the quadruple aim of value-based care through providing people with musculoskeletal disease improved access to health services, better health outcomes and satisfactory experience of their healthcare; ensure the health professionals involved are experiencing satisfaction in delivering such care and health system resources are better utilised. Implementation of MoCs is relevant at the levels of clinical practice (micro), service delivery organisations (meso) and health system (macro) levels. The development, implementation and evaluation of MoCs has evolved over the last decade to more purposively engage people with lived experience of their condition, to operationalise the Chronic Care Model and to employ innovative solutions. This paper explores how MoCs have evolved and are supporting the delivery of value-based care in health systems.

Identification of Risk Factors and Machine Learning-Based Prediction Models for Knee Osteoarthritis Patients

Knee Osteoarthritis (KOA) is a multifactorial disease that causes low quality of life, poor psychology and resignation from life. Furthermore, KOA is a big data problem in terms of data complexity, heterogeneity and size as it has been commonly considered in the literature with most of the reported studies being limited in the amount of information they can adequately process. The aim of this paper is: (i) To provide a robust feature selection (FS) approach that could identify important risk factors which contribute to the prediction of KOA and (ii) to develop machine learning (ML) prediction models for KOA. The current study considers multidisciplinary data from the osteoarthritis initiative (OAI) database, the available features of which come from heterogeneous sources such as questionnaire data, physical activity indexes, self-reported data about joint symptoms, disability and function as well as general health and physical exams’ data. The novelty of the proposed FS methodology lies on the combination of different well-known approaches including filter, wrapper and embedded techniques, whereas feature ranking is decided on the basis of a majority vote scheme to avoid bias. The validation of the selected factors was performed in data subgroups employing seven well-known classifiers in five different approaches. A 74.07% classification accuracy was achieved by SVM on the group of the first fifty-five selected risk factors. The effectiveness of the proposed approach was evaluated in a comparative analysis with respect to classification errors and confusion matrices to confirm its clinical relevance. The results are the basis for the development of reliable tools for the prediction of KOA progression.

Vitamin K in Vertebrates' Reproduction: Further Puzzling Pieces of Evidence from Teleost Fish Species

Vitamin K (VK) is a fat-soluble vitamin that vertebrates have to acquire from the diet, since they are not able to de novo synthesize it. VK has been historically known to be required for the control of blood coagulation, and more recently, bone development and homeostasis. Our understanding of the VK metabolism and the VK-related molecular pathways has been also increased, and the two main VK-related pathways-the pregnane X receptor (PXR) transactivation and the co-factor role on the γ-glutamyl carboxylation of the VK dependent proteins-have been thoroughly investigated during the last decades. Although several studies evidenced how VK may have a broader VK biological function than previously thought, including the reproduction, little is known about the specific molecular pathways. In vertebrates, sex differentiation and gametogenesis are tightly regulated processes through a highly complex molecular, cellular and tissue crosstalk. Here, VK metabolism and related pathways, as well as how gametogenesis might be impacted by VK nutritional status, will be reviewed. Critical knowledge gaps and future perspectives on how the different VK-related pathways come into play on vertebrate's reproduction will be identified and proposed. The present review will pave the research progress to warrant a successful reproductive status through VK nutritional interventions as well as towards the establishment of reliable biomarkers for determining proper nutritional VK status in vertebrates.

Guidance for implementing best practice therapeutic exercise for people with knee and hip osteoarthritis: what does the current evidence base tell us?

OBJECTIVE

Therapeutic exercise is a recommended first-line treatment for people with knee and hip osteoarthritis. However, there is little specific advice or practical resources to guide clinicians in its implementation. As the first in a series of projects by the Osteoarthritis Research Society International Rehabilitation Discussion Group to address this gap, we aim to synthesize current literature informing the implementation of therapeutic exercise for people with knee and hip osteoarthritis.

METHODS

Narrative review focusing on evidence from systematic reviews and randomized controlled trials.

RESULTS

Therapeutic exercise is safe for people with knee and hip osteoarthritis. Numerous types of therapeutic exercise (including aerobic, strengthening, neuromuscular, mind-body exercise) may be utilised at varying doses and in different settings to improve pain and function. Benefits from therapeutic exercise appear greater when dosage recommendations from general exercise guidelines for healthy adults are met. However, interim therapeutic exercise goals may also be useful, given that many barriers to achieving these dosages exist among this patient group. Theoretically-informed strategies to improve adherence to therapeutic exercise, such as patient education, goal setting, monitoring and feedback, may help maintain participation and optimise clinical benefits over the longer-term. Sedentary behaviour is also a risk factor for disability and lower quality of life in people with knee and hip osteoarthritis, although limited evidence exists regarding how best to reduce this behaviour.

CONCLUSION

Current evidence can be used to inform how to implement best practice therapeutic exercise, at a sufficient and appropriate dose, for people with knee and hip osteoarthritis.

Detection of subclinical skin manifestation in patients with psoriasis and psoriatic arthritis by fluorescence optical imaging

OBJECTIVES

To investigate the frequency of subclinical skin inflammation in both hands by fluorescence optical imaging (FOI) in patients with psoriasis/psoriatic arthritis (Pso/PsA) vs. rheumatoid arthritis (RA) and healthy individuals, and to correlate these findings with cardiovascular (CV) risk factors.

PATIENTS AND METHODS

The FOI scans were analyzed retrospectively to detect clinically invisible skin enhancement (0-3 scale) in both hands without relationship to underlying joints or blood vessels. We further characterized the FOI patterns and sorted the scans into groups based on the assumed diagnosis (Pso/PsA, RA, and healthy controls), which was compared with the physician's diagnosis. Furthermore, the associations between CV risk factors and imaging findings were investigated by regression analyses.

RESULTS

We included FOI scans of patients with Pso/PsA (n = 80), RA (n = 78), and healthy controls (n = 25). Subclinical skin enhancement on the back of their hands was more common in Pso/PsA (72.5%) than in RA patients (20.5%) and healthy individuals (28.0%) (p < 0.001). Based on the FOI pattern, the majority of patients with Pso/PsA (72.5%), RA (76.9%), and healthy controls (68.0%) were classified correctly using the physician-based diagnosis as reference (overall agreement of 74%, kappa = 0.57). No CV risk factors except body weight (kg) were associated with subclinical skin enhancement (OR 1.04, 95% CI 1.02-1.06; p < 0.001).

CONCLUSION

Subclinical subdermal skin inflammation was common in Pso/PsA patients using FOI. Based on the FOI pattern, most patients with Pso/PsA and were classified with the correct diagnosis. We demonstrated an important influence of the body weight on our FOI results. FOI may be a helpful novel tool to study microcirculation in rheumatic diseases with skin involvement.

Occupation and risk of knee osteoarthritis and knee replacement: A longitudinal, multiple-cohort study

OBJECTIVES

To examine the effect of occupation on knee osteoarthritis (OA) and total knee replacement (TKR) in working-aged adults.

METHODS

We used longitudinal data from the Chingford, Osteoarthritis Initiative (OAI) and Multicentre Osteoarthritis (MOST) studies. Participants with musculoskeletal disorders and/or a history of knee-related surgery were excluded. Participants were followed for up to 19-years (Chingford), 96-months (OAI) and 60-months (MOST) for incident outcomes including radiographic knee OA (RKOA), symptomatic RKOA and TKR. In those with baseline RKOA, progression was defined as the time from RKOA incidence to primary TKR. Occupational job categories and work-place physical activities were assigned to levels of workload. Logistic regression was used to examine the relationship between workload and incident outcomes with survival analyses used to assess progression (reference group: sedentary occupations).

RESULTS

Heavy manual occupations were associated with a 2-fold increased risk (OR: 2.07, 95% CI 1.03 to 4.15) of incident RKOA in the OAI only. Men working in heavy manual occupations in MOST (2.7, 95% CI 1.17 to 6.26) and light manual occupations in OAI (2.00, 95% CI 1.09 to 3.68) had a 2-fold increased risk of incident RKOA. No association was observed among women. Increasing workload was associated with an increased risk of symptomatic RKOA in the OAI and MOST. Light work may be associated with a decreased risk of incident TKR and disease progression.

CONCLUSION

Heavy manual work carries an increased risk of incident knee OA; particularly among men. Workload may influence the occurrence of TKR and disease progression.

Long term efficacy of mobilisation with movement on pain and functional status in patients with knee osteoarthritis: a randomised clinical trial

OBJECTIVES

To evaluate the long term effect of mobilisation with movement on disability, pain and function in subjects with symptomatic knee osteoarthritis.

DESIGN

A randomised controlled trial.

SETTING

A general hospital.

SUBJECTS

Forty adults with knee osteoarthritis (grade 1-3 Kellgren-Lawrence scale).

INTERVENTIONS

The experimental group received mobilisation with movement and usual care (exercise and moist heat) while the control group received usual care alone in six sessions over two weeks.

MAIN MEASURES

The primary outcome was the Western Ontario McMaster University Osteoarthritis index, higher scores indicating greater disability. Pain intensity over 24 hours and during sit to stand were measured on a 10 centimetre visual analogue scale. Functional outcomes were the timed up and go test, the 12 step stair test, and knee range of motion. Patient satisfaction was measured on an 11 point numerical rating scale. Variables were evaluated blind pre- and post intervention, and at three and six months follow-up.

RESULTS

Thirty five participants completed the study. At each follow-up including six-months, significant differences were found between groups favouring those receiving mobilisation with movement for all variables except knee mobility. The primary outcome disability showed a mean difference of 7.4 points (95% confidence interval, 4.5 to 10.3) at six-months and a mean difference of 13.6 points (95% confidence interval, 9.3 to 17.9) at three-months follow-up.

CONCLUSION

In patients with symptomatic knee osteoarthritis, the addition of mobilisation with movement provided clinically significant improvements in disability, pain, functional activities and patient satisfaction six months later.

Barriers to and Facilitators of Physical Activity among Korean Female Adults with Knee Osteoarthritis and Comorbidity: A Qualitative Study

When knee osteoarthritis is combined with comorbidity, it is associated with limited physical activity. This study aimed to identify barriers to and facilitators of physical activity among Korean female adults with knee osteoarthritis and comorbidity, such as hypertension, diabetes, and dyslipidemia. A qualitative content analysis study was conducted. Ten female knee osteoarthritis participants with comorbidity were recruited at an orthopedic outpatient center in South Korea. Data were collected using in-depth interviews and were analyzed using a conventional content analysis method. Ten participants with a mean age of 70.7 years participated in this study. Four categories of barriers and three of facilitators were identified. Barriers to physical activity were physical hardships, lack of motivation, environmental restrictions, and lack of knowledge. Categories of facilitators were pain management, self-control in physical activity, and understanding the importance of physical activity. Participants did not express any social or environmental facilitators of physical exercise. Healthcare professionals should include social support and environmental facilities to achieve medical and institutional compliance. Understanding female adults with knee osteoarthritis and comorbidity would support provision of appropriately tailored interventions that account for the characteristics of the comorbidity.

Validity and diagnostic performance of fluorescence optical imaging measuring synovitis in hand osteoarthritis: baseline results from the Nor-Hand cohort

OBJECTIVE

Fluorescence optical imaging (FOI) demonstrates enhanced microcirculation in finger joints as a sign of inflammation. We wanted to assess the validity and diagnostic performance of FOI measuring synovitis in persons with hand OA, comparing it with magnetic resonance imaging (MRI)- and ultrasound-detected synovitis.

METHODS

Two hundred and twenty-one participants with hand OA underwent FOI and ultrasound (gray-scale synovitis and power Doppler activity) of the bilateral hands and contrast-enhanced MRI examination of the dominant hand. Fifteen joints in each hand were scored on semi-quantitative scales (grade 0-3) for all modalities. Four FOI images were evaluated: one composite image (Prima Vista Mode (PVM)) and three images representing phases of fluorescent dye distribution. Spearman's correlation coefficients were calculated between sum scores of FOI, MRI, and ultrasound. Sensitivity, specificity, and area under the curve (AUC) were calculated for FOI using MRI or ultrasound as reference.

RESULTS

FOI did not demonstrate enhancement in the thumb base, and the joint was excluded from further analyses. FOI sum scores showed poor to fair correlations with MRI (rho 0.01-0.24) and GS synovitis sum scores (rho 0.12-0.25). None of the FOI images demonstrated both good sensitivity and specificity, and the AUC ranged from 0.50-0.61 and 0.51-0.63 with MRI and GS synovitis as reference, respectively. FOI demonstrated similar diagnostic performance with PD activity and GS synovitis as reference.

CONCLUSION

FOI enhancement correlated poorly with synovitis assessed by more established imaging modalities, questioning the value of FOI for the evaluation of synovitis in hand OA.