Reproducible microbiome composition signatures of anxiety and depressive symptoms.

The gut microbiome is a significant contributor to mental health, with growing evidence linking its composition to anxiety and depressive disorders. Gut microbiome composition is associated with signs of anxiety and depression both in clinically diagnosed mood disorders and subclinically in the general population and may be influenced by dietary fibre intake and the presence of chronic pain. We provide an update of current evidence on the role of gut microbiome composition in depressive and anxiety disorders or symptoms by reviewing available studies. Analysing data from three independent cohorts (osteoarthritis 1 (OA1); n = 46, osteoarthritis 2 (OA2); n = 58, and healthy controls (CON); n = 67), we identified microbial composition signatures of anxiety and depressive symptoms at genus level and cross-validated our findings performing meta-analyses of our results with results from previously published studies. The genera Bifidobacterium (fixed-effect beta (95% CI) = -0.22 (-0.34, -0.10), p = 3.90e-04) and Lachnospiraceae NK4A136 group (fixed-effect beta (95% CI) = -0.09 (-0.13, -0.05), p = 2.53e-06) were found to be the best predictors of anxiety and depressive symptoms, respectively, across our three cohorts and published literature taking into account demographic and lifestyle covariates, such as fibre intake. The association with anxiety was robust in accounting for heterogeneity between cohorts and supports previous observations of the potential prophylactic effect of Bifidobacterium against anxiety symptoms.

The Web-Based Pain-at-Work Toolkit With Telephone Support for Employees With Chronic or Persistent Pain: Protocol for a Cluster Randomized Feasibility Trial.

BACKGROUND: Chronic or persistent pain affects one's ability to work or be productive at work, generating high societal and economic burden. However, the provision of work-related advice and support for people with chronic pain is variable or lacking. The Pain-at-Work (PAW) Toolkit was cocreated with people who live with pain, health care professionals, and employers. It aims to increase knowledge about employee rights and how to access support for managing a painful chronic condition in the workplace and provides advice on lifestyle behaviors that facilitate the management of chronic pain. OBJECTIVE: We aimed to establish the feasibility of conducting a definitive cluster randomized controlled trial comparing access to the PAW Toolkit and telephone support calls from an occupational therapist (PAW) with treatment as usual (ie, standard support from their employer). Our primary outcomes are establishing parameters of feasibility, acceptability, usability, and safety of this digital workplace health intervention. We will assess the candidate primary and secondary outcomes' feasibility and test research processes for a definitive trial. METHODS: This is an open-label, parallel 2-arm pragmatic feasibility cluster randomized controlled trial with exploratory health economics analysis and a nested qualitative interview study. We aim to recruit 120 participants from at least 8 workplace clusters (any type, >10 employees) in England. The recruitment of workplaces occurs via personal approach, and the recruitment of individual participants is web based. Eligible participants are vocationally active adults aged ≥18 years with internet access and self-reporting chronic pain interfering with their ability to undertake or enjoy productive work. A restricted 1:1 cluster-level randomization is used to allocate employment settings to PAW or treatment as usual; participants are unblinded to group allocation. Following site- and individual-level consent, participants complete a web-based baseline survey (time 0), including measures of work capacity, health and well-being, and health care resource use. Follow-up is performed at 3 months (time 1) and 6 months (time 2). Feasibility outcomes relate to recruitment; intervention fidelity (eg, delivery, reach, uptake, and engagement); retention; and follow-up. Qualitative evaluation (time 2) is mapped to the Capability, Opportunity, Motivation-Behavior model and will explore intervention acceptability to employees and employers, along with individual and contextual factors influencing the delivery and uptake of the intervention. RESULTS: Ethics approval was obtained in March 2023. Trial recruitment began in June 2023. CONCLUSIONS: The PAW Toolkit is the first evidence-based digital health intervention aimed at supporting the self-management of chronic or persistent pain at work. This study will inform the design of a definitive trial, including sample size estimation, approaches to cluster site identification, primary and secondary outcomes' selection, and the final health economic model. Findings will inform approaches for the future delivery of this digital health intervention. TRIAL REGISTRATION: ClinicalTrials.gov NCT05838677; https://clinicaltrials.gov/study/NCT05838677. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/51474.

Is there a difference in the analgesic response to intra-articular bupivacaine injection in people with knee osteoarthritis pain with or without central sensitisation? Protocol of a feasibility randomised controlled trial.

INTRODUCTION: Pain is the main symptom of osteoarthritis (OA) with approximately 50% of patients reporting moderate-to-severe pain. Total knee replacement (TKR) is the ultimate treatment option to alleviate pain in knee OA. Nevertheless, TKR does not provide complete relief for all as approximately 20% of patients experience chronic postoperative pain. Painful peripheral stimuli may alter the central nociceptive pathways leading to central sensitisation that can influence treatment response in patients with OA. Currently, there is no objective protocol for detecting whether a patient will respond to a given treatment. Therefore, there is a need for a better mechanistic understanding of individual factors affecting pain relief, consequently informing personalised treatment guidelines. The purpose of this research is to examine the feasibility of conducting a full-scale mechanistic clinical trial in painful knee OA investigating the analgesic response to intra-articular bupivacaine between those with or without evidence of central sensitisation. METHODS AND ANALYSIS: The Understanding Pain mechanisms in KNEE osteoarthritis (UP-KNEE) study is a feasibility, double-blinded, placebo-controlled randomised parallel study in participants with radiographically defined knee OA and with self-reported chronic knee pain. The study involves the following assessments: (1) a suite of psychometric questionnaires; (2) quantitative sensory testing; (3) magnetic resonance imaging (MRI) scan of the knee and brain; (4) a 6-minute walk test; and (5) an intra-articular injection of bupivacaine or placebo (sodium chloride 0.9%) into the index knee. Assessments will be repeated post intra-articular injection apart from the MRI scan of the knee. Our aim is to provide proof of concept and descriptive statistics to power a future mechanistic trial. ETHICS AND DISSEMINATION: Ethical approval was obtained from the Health Research Authority (HRA) (REC: 20/EM/0287). Results will be disseminated via peer-reviewed journals and scientific conferences. The results will also be shared with lay audiences through relevant channels, such as Pain Centre Versus Arthritis website and patient advocacy groups. TRIAL REGISTRATION NUMBER: NCT05561010.

Acceptability of a nurse-led non-pharmacological complex intervention for knee pain: Nurse and patient views and experiences.

OBJECTIVES: The overall purpose of this research programme is to develop and test the feasibility of a complex intervention for knee pain delivered by a nurse, and comprising both non-pharmacological and pharmacological interventions. In this first phase, we examined the acceptability of the non-pharmacological component of the intervention; issues faced in delivery, and resolved possible challenges to delivery. METHODS: Eighteen adults with chronic knee pain were recruited from the community. The intervention comprised holistic assessment, education, exercise, weight-loss advice (where appropriate) and advice on adjunctive treatments such as hot/cold treatments, footwear modification and walking aids. After nurse training, the intervention was delivered in four sessions spread over five weeks. Participants had one to one semi-structured interview at the end of the intervention. The nurse was interviewed after the last visit of the last participant. These were audio recorded and transcribed verbatim. Themes were identified by one author through framework analysis of the transcripts, and cross-checked by another. RESULTS: Most participants found the advice from the nurse easy to follow and were satisfied with the package, though some felt that too much information was provided too soon. The intervention changed their perception of managing knee pain, learning that it can be improved with self-management. However, participants thought that the most challenging part of the intervention was fitting the exercise regime into their daily routine. The nurse found discussion of goal setting to be challenging. CONCLUSION: The nurse-led package of care is acceptable within a research setting. The results are promising and will be applied in a feasibility randomised-controlled trial.

Fatigue in early rheumatoid arthritis: data from the Early Rheumatoid Arthritis Network.

OBJECTIVES: Fatigue is a disabling symptom in people with RA. This study aims to describe the prevalence, risk factors and longitudinal course of fatigue in early RA. METHODS: Demographic, clinical, quality of life (QoL), comorbidities and laboratory data were from the Early RA Network (ERAN), a UK multicentre inception cohort of people with RA. Fatigue was measured using the vitality subscale of the 36-item Short Form Health Survey, where higher values represent better QoL. Baseline prevalences of fatigue classifications were age and sex standardized. Linear regression, hierarchical growth curve modelling and group-based trajectory modelling (GBTM) were utilized. RESULTS: At baseline (n = 1236, 67% female, mean age 57 years), the mean vitality was 41 (s.d. 11) and disease duration was 11 months (interquartile range 7-18). Age- and sex-standardized prevalence rates of fatigue and severe fatigue were 44% (95% CI 39, 50) and 19% (95% CI 15, 23), respectively. Fatigue changed little over 3 years and five measurement occasions ß = -0.13 (95% CI -0.23, -0.02). GBTM identified two subgroups, which we named 'Fatigue' (53%) and 'No-fatigue' (47%). Female sex, worse pain, mental health and functional ability were associated with greater fatigue and predicted Fatigue group membership (area under the receiver operating characteristics curve = 0.81). Objective measures of inflammation-swollen joint count and ESR-were not significantly associated with fatigue. CONCLUSIONS: Fatigue is prevalent and persistent in early RA. Diverse characteristics indicative of central mechanisms are associated with persistent fatigue. Management of fatigue might require interventions targeted at central mechanisms in addition to inflammatory disease modification. People who require such interventions might be identified at presentation with early RA.

Neuropathic-like knee pain and associated risk factors: a cross-sectional study in a UK community sample.

BACKGROUND: Neuropathic-like knee pain (NKP) is often reported in individuals with knee pain (KP), but the contribution of specific central and peripheral risk factors to NKP has not been studied previously. The aims of the present study were to determine the prevalence of NKP in a community-derived sample with KP and to identify risk factors associated with NKP. METHODS: A cross-sectional study was undertaken (n = 9506) in the East Midlands community among responders (aged 40+ years) to a postal questionnaire. Questions included KP severity (numerical rating scale) and type (neuropathic versus nociceptive) using the modified painDETECT questionnaire, as well as age, body mass index (BMI), significant knee injury, widespread pain, pain catastrophising and fatigue. Multinomial regression analysis was used to determine ORs and 95% CIs. Risk factors were categorised into central and peripheral, and proportional risk contribution (PRC) and 95% CI were estimated using ROC. RESULTS: KP was reported in 28.2% of responders, of whom 13.65% had NKP (i.e., 3.9% of the total population). Women reported more NKP. After adjustment for age, gender, BMI and pain severity, definite NKP showed associations (aOR, 95% CI) with fibromyalgia (4.07, 2.49-6.66), widespread pain (1.93, 1.46-2.53), nodal osteoarthritis (1.80, 1.28-2.53), injury (1.50, 1.12-2.00), pain catastrophising (5.37, 2.93-9.84) and fatigue (5.37, 3.08-9.35) compared with non-NKP participants. Although only central risk factors contributed to NKP (PRC 8%, 95% CI 2.5-12.5 for central vs. PRC 3%, 95% CI -0.25 to 7.5 for peripheral), both central and peripheral risk factors contributed equally to non-NKP (PRC 10%, 95% CI 5-20 for both). CONCLUSIONS: NKP appears to be driven largely by central risk factors and may require different prevention/treatment strategies. TRIAL REGISTRATION: ClinicalTrials.gov , NCT02098070 . Registered on 27 March 2014.

Can Rheumatologists Predict Eventual Need for Orthopaedic Intervention in Patients with Rheumatoid Arthritis? Results of a Systematic Review and Analysis of Two UK Inception Cohorts.

PURPOSE OF REVIEW: The structural damage caused by rheumatoid arthritis (RA) can often be mitigated by orthopaedic surgery in late disease. This study evaluates the value of predictive factors for orthopaedic intervention. METHODS: A systematic review of literature was undertaken to identify papers describing predictive factors for orthopaedic surgery in RA. Manuscripts were selected if they met inclusion criteria of cohort study design, diagnosis of RA, follow-up duration/disease duration ≥3 years, any orthopaedic surgical interventions recorded, and then summarised for predictive factors. A separate predictive analysis was performed on two consecutive UK Early RA cohorts, linked to national datasets. RECENT FINDINGS: The literature search identified 15 reports examining predictive factors for orthopaedic intervention, 4 inception, 5 prospective and 6 retrospective. Despite considerable variation, acute phase, x-ray scores, women and genotyping were the most commonly reported prognostic markers. The current predictive analysis included 1602 procedures performed in 711 patients (25-year cumulative incidence 26%). Earlier recruitment year, erosions and lower haemoglobin predicted both intermediate and major surgery (P<0.05). Studies report variations in type of and predictive power of clinical and laboratory parameters for different surgical interventions suggesting specific contributions from different pathological and/or patient-level factors. Our current analysis suggests that attention to non-inflammatory factors in addition to suppression of inflammation is needed to minimise the burden of orthopaedic surgery.

Reductions in Radiographic Progression in Early Rheumatoid Arthritis Over Twenty-Five Years: Changing Contribution From Rheumatoid Factor in Two Multicenter UK Inception Cohorts.

OBJECTIVE: To assess the 5-year progression of erosions and joint space narrowing (JSN) and their associations with rheumatoid factor (RF) status in 2 large, multicenter, early rheumatoid arthritis cohorts, spanning 25 years. METHODS: Radiographic joint damage was recorded using the Sharp/van der Heijde (SHS) method in the Early Rheumatoid Arthritis Study (ERAS), 1986-2001, and the Early Rheumatoid Arthritis Network (ERAN), 2002-2013. Mixed-effects negative binomial regression estimated changes in radiographic damage over 5 years, including erosions and JSN, separately. RF, along with age, sex, and baseline markers of disease activity were controlled for. RESULTS: A total of 1,216 patients from ERAS and 446 from ERAN had radiographic data. Compared to ERAS, ERAN patients had a lower mean total SHS score at baseline (ERAN 6.2 versus ERAS 10.5; P < 0.001) and mean annual rate of change (ERAN 2.5 per year versus ERAS 6.9 per year; P < 0.001). Seventy-four percent of ERAS and 27% of ERAN patients progressed ≥5 units. Lower scores at baseline in ERAN were largely driven by reductions in JSN (ERAS 3.9 versus ERAN 1.2; P < 0.001), along with erosions (ERAS 1.9 versus ERAN 0.8; P < 0.001). RF was associated with greater progression in each cohort, but the absolute difference in mean annual rate of change for RF-positive patients was substantially higher for ERAS (RF positive 8.6 versus RF negative 5.1; P < 0.001), relative to ERAN (RF positive 2.0 versus RF negative 1.9; P = 0.855). CONCLUSION: Radiographic progression was shown to be significantly reduced between the 2 cohorts, and was associated with lower baseline damage and other factors, including changes in early disease-modifying antirheumatic drug use. The impact of RF status as a prognostic marker of clinically meaningful change in radiographic progression has markedly diminished in the context of more modern treatment.

Association between rheumatoid arthritis disease activity, progression of functional limitation and long-term risk of orthopaedic surgery: combined analysis of two prospective cohorts supports EULAR treat to target DAS thresholds.

OBJECTIVES: To examine the association between disease activity in early rheumatoid arthritis (RA), functional limitation and long-term orthopaedic episodes. METHODS: Health Assessment Questionnaire (HAQ) disability scores were collected from two longitudinal early RA inception cohorts in routine care; Early Rheumatoid Arthritis Study and Early Rheumatoid Arthritis Network from 1986 to 2012. The incidence of major and intermediate orthopaedic surgical episodes over 25 years was collected from national data sets. Disease activity was categorised by mean disease activity score (DAS28) annually between years 1 and 5; remission (RDAS≤2.6), low (LDAS>2.6-3.2), low-moderate (LMDAS≥3.2-4.19), high-moderate (HMDAS 4.2-5.1) and high (HDAS>5.1). RESULTS: Data from 2045 patients were analysed. Patients in RDAS showed no HAQ progression over 5 years, whereas there was a significant relationship between rising DAS28 category and HAQ at 1 year, and the rate of HAQ progression between years 1 and 5. During 27 986 person-years follow-up, 392 intermediate and 591 major surgeries were observed. Compared with the RDAS category, there was a significantly increased cumulative incidence of intermediate surgery in HDAS (OR 2.59 CI 1.49 to 4.52) and HMDAS (OR 1.8 CI 1.05 to 3.11) categories, and for major surgery in HDAS (OR 2.48 CI 1.5 to 4.11), HMDAS (OR 2.16 CI 1.32 to 3.52) and LMDAS (OR 2.07 CI 1.28 to 3.33) categories. There was no significant difference in HAQ progression or orthopaedic episodes between RDAS and LDAS categories. CONCLUSIONS: There is an association between disease activity and both poor function and long-term orthopaedic episodes. This illustrates the far from benign consequences of persistent moderate disease activity, and supports European League Against Rheumatism treat to target recommendations to secure low disease activity or remission in all patients.

Augmented pain behavioural responses to intra-articular injection of nerve growth factor in two animal models of osteoarthritis.

OBJECTIVES: Nerve growth factor (NGF) is a promising analgesic target, particularly in osteoarthritis (OA) where existing therapies are inadequate. We hypothesised that pain responses to NGF are increased in OA joints. Here, NGF-evoked pain behaviour was compared in two rodent models of OA, and possible mechanisms underlying altered pain responses were examined. METHODS: OA was induced in rat knees by meniscal transection (MNX) or intra-articular monosodium iodoacetate injection (MIA). Once OA pathology was fully established (day 20), we assessed pain behaviour (hindlimb weight-bearing asymmetry and hindpaw mechanical withdrawal thresholds) evoked by intra-articular injection of NGF (10 µg). Possible mechanisms underlying alterations in NGF-induced pain behaviour were explored using indomethacin pretreatment, histopathological evaluation of synovitis, and rtPCR for NGF receptor (tropomyosin receptor kinase (Trk)-A) expression in dorsal root ganglia (DRG). RESULTS: Both the MIA and MNX models of OA displayed reduced ipsilateral weight bearing and hindpaw mechanical withdrawal thresholds, mild synovitis and increased TrkA expression in DRG. NGF injection into OA knees produced a prolonged augmentation of weight-bearing asymmetry, compared to NGF injection in non-osteoarthritic knees. However, hindpaw mechanical withdrawal thresholds were not further decreased by NGF. Pretreatment with indomethacin attenuated NGF-facilitated weight-bearing asymmetry and reversed OA-induced ipsilateral TrkA mRNA up-regulation. CONCLUSIONS: OA knees were more sensitive to NGF-induced pain behaviour compared to non-osteoarthritic knees. Cyclo-oxygenase products may contribute to increased TrkA expression during OA development, and the subsequent increased NGF sensitivity. Treatments that reduce sensitivity to NGF have potential to improve OA pain.

Cognitive and affective reassurance and patient outcomes in primary care: a systematic review.

In the context of uncertainty about aetiology and prognosis, good clinical practice commonly recommends both affective (creating rapport, showing empathy) and cognitive reassurance (providing explanations and education) to increase self-management in groups with nonspecific pain conditions. The specific impact of each of these components in reference to patients' outcomes has not been studied. This review aimed to systematically evaluate the evidence from prospective cohorts in primary care that measured patient-practitioner interactions with reference to patient outcomes. We carried out a systematic literature search and appraisal of study methodology. We extracted measures of affective and cognitive reassurance in consultations and their associations with consultation exit and follow-up measures of patients' outcomes. We identified 16 studies from 16,059 abstracts. Eight studies were judged to be high in methodological quality. Pooling could not be achieved as a result of heterogeneity of samples and measures. Affective reassurance showed inconsistent findings with consultation exit outcomes. In 3 high-methodology studies, an association was found between affective reassurance and higher symptom burden and less improvement at follow-up. Cognitive reassurance was associated with higher satisfaction and enablement and reduced concerns directly after the consultations in 8 studies; with improvement in symptoms at follow-up in 7 studies; and with reduced health care utilization in 3 studies. Despite limitations, there is support for the notion that cognitive reassurance is more beneficial than affective reassurance. We present a tentative model based on these findings and propose priorities for future research.

Mindfulness, functioning and catastrophizing after multidisciplinary pain management for chronic low back pain.

We examined mindfulness in people with chronic low back pain who were attending a multidisciplinary pain management programme. Participants completed questionnaires at baseline (n=116) and after a 3-month cognitive-behaviourally informed multidisciplinary intervention (n=87). Self-reported mindfulness was measured before and after the intervention, and relationships were explored between mindfulness, disability, affect and pain catastrophizing. Mindfulness increased following participation in the intervention, and greater mindfulness was predictive of lower levels of disability, anxiety, depression and catastrophizing, even when pain severity was controlled. Mediator analyses suggested that the relationship between mindfulness and disability was mediated by catastrophizing. It is possible that cognitive-behavioural interventions and processes can affect both catastrophizing and mindfulness.

Increased vascular penetration and nerve growth in the meniscus: a potential source of pain in osteoarthritis.

OBJECTIVES: Meniscal damage is a recognised feature of knee osteoarthritis (OA), although its clinical relevance remains uncertain. This study describes vascular penetration and nerve growth in human menisci, providing a potential mechanism for the genesis of pain in knee OA. METHODS: Menisci obtained post mortem were screened on the basis of high or low macroscopic tibiofemoral chondropathy as a measure of the presence and degree of OA. Forty cases (20 per group) were selected for the study of meniscal vascularity, and 16 (eight per group) for the study of meniscal innervation. Antibodies directed against α-actin and calcitonin gene-related peptide (CGRP) were used to localise blood vessels and nerves by histochemistry. Image analysis was used to compare vascular and nerve densities between groups. Data are presented as median (IQR). RESULTS: Menisci from knees with high chondropathy displayed degeneration of collagen bundles in their outer regions, which were more vascular than the inner regions, with an abrupt decrease in vascularity at the fibrocartilage junction. Vascular densities were increased in menisci from the high compared with low chondropathy group both in the synovium (3.8% (IQR 2.6-5.2), 2.0% (IQR 1.4-2.9), p=0.002) and at the fibrocartilage junction (2.3% (IQR 1.7-3.1), 1.1% (IQR 0.8-1.9), p=0.003), with a greater density of perivascular sensory nerve profiles in the outer region (high chondropathy group, 144 nerve profiles/mm(2) (IQR 134-189); low chondropathy group, 119 nerve profiles/mm(2) (IQR 104-144), p=0.049). CONCLUSION: Tibiofemoral chondropathy is associated with altered matrix structure, increased vascular penetration, and increased sensory nerve densities in the medial meniscus. The authors suggest therefore that angiogenesis and associated sensory nerve growth in menisci may contribute to pain in knee OA.

Explanatory and diagnostic labels and perceived prognosis in chronic low back pain.

STUDY DESIGN: Content analysis of patient interviews, clinic letters, and radiology reports for patients with chronic low back pain of greater than 12 months duration. OBJECTIVE: To explore the language used by patients and healthcare professionals to describe low back pain and any potential effect on patient perceived prognosis. SUMMARY OF BACKGROUND DATA: Diagnostic explanations by healthcare professionals may influence patient coping and uptake of therapy by patients with chronic low back pain. Although the correlation between radiologic changes and chronic low back pain is weak, these investigations are often used by clinicians as an explanation of the underlying cause for the pain. METHODS: Patients were asked about their understanding of the mechanisms underlying their pain, flares, and future outcome. Notes from these interviews were transcribed, along with correspondence from primary care physicians, orthopedic surgeons and pain physicians, and lumbar spine radiology reports for these patients. Content analysis was performed to identify and group key terms. RESULTS: Two major categories representing the predominant themes emerging from the content analysis were "Degeneration" and "Mechanical." Degenerative terms such as "wear and tear" and "disc space loss" indicated a progressive loss of structural integrity. Examples of phrases used by patients included "deterioration […] spine is crumbling" and "collapsing […] discs wearing out." The use of degenerative terms by patients was associated with a poor perceived prognosis (P < 0.01). Degenerative and mechanical terms were more commonly used by patients when they were documented in correspondence from secondary care specialists (P = 0.03 and 0.01, respectively). CONCLUSION: A common language is shared between professionals and patients that may encourage unhelpful beliefs. The use of degenerative terms such as wear and tear by patients is associated with a poor perceived prognosis. The explanation of radiological findings to patients presents an opportunity to challenge unhelpful beliefs, thus facilitating uptake of active treatment strategies.

Angiogenesis in osteoarthritis.

PURPOSE OF REVIEW: Much has been documented in recent years on the possible involvement of angiogenesis in osteoarthritis. An understanding of the various regulatory mechanisms controlling blood vessel growth in the joint should lead to novel therapeutics, which selectively inhibit undesirable angiogenesis. Here, we summarize recent findings on the roles of angiogenesis in osteoarthritis and place this evidence in the context of previous literature in order to help explain pain and disease progression. RECENT FINDINGS: Inflammation and angiogenesis are closely associated in osteoarthritis, modulating functions of chondrocytes, contributing towards abnormal tissue growth and perfusion, ossification and endochondral bone development, leading to radiographic changes observed in the joint. Innervation accompanies vascularization and inflammation, hypoxia and mechanical overload are all thought to contribute in sensitizing these new nerves leading to increased pain. Articular cartilage provides a unique environment in which blood vessel growth is regulated by endogenous angiogenesis inhibitors and matrix constituents, as well as by growth factors produced by chondrocytes, subchondral bone and synovium. MRI and ultrasound enable the in-vivo visualization of abnormal vascularity in synovium and subchondral bone that have not been apparent with conventional radiography. As a result of these new findings, the widely accepted notion that osteoarthritis is primarily a disease of the cartilage is being challenged. SUMMARY: Molecular mechanisms and consequences of angiogenesis in osteoarthritis are slowly being elucidated. Studies, both in humans and animal models, support the notion that inhibiting angiogenesis will provide effective therapeutic strategies for treating osteoarthritis. Better techniques that can more precisely visualize the vascular changes of the whole joint can further enhance our understanding of osteoarthritis, and can provide proof of concept and early evidence of efficacy in trials of novel therapeutic interventions.

Beliefs about the causes and consequences of pain in patients with chronic inflammatory or noninflammatory low back pain and in pain-free individuals.

STUDY DESIGN: Case control study including 2 groups of patients with low back pain (LBP, inflammatory and noninflammatory) and a pain-free community control group. OBJECTIVE: We explored whether pain beliefs differ between patients with chronic LBP attributed to inflammatory or noninflammatory medical diagnoses, and between patients with chronic LBP and pain-free controls. SUMMARY OF BACKGROUND DATA: Beliefs strongly influence patients' engagement in and response to treatments for chronic LBP. It is unclear, however, whether unhelpful beliefs held by patients with chronic LBP are predominantly associated with diagnosis, or with other aspects of the patient's pain experience. METHODS: Patients and controls completed the pain beliefs questionnaire addressing beliefs about the causes and consequences of pain. Patients also completed questionnaires addressing catastrophizing (Coping Strategies Questionnaire), physical disability and bodily pain (SF-36 Health Survey), and psychological distress (Spielberger State-Trait Anxiety Inventory Short Form and Cognitive Depression Index). Variance analysis and chi2 test were used as appropriate, adjusting for effects of covariates and multiple comparisons. Linear regression and logistic regression were used to adjust for confounding factors. RESULTS: Patients with noninflammatory LBP more strongly endorsed organic pain beliefs (e.g., that pain necessarily indicates damage), and catastrophizing (e.g., that the pain is never going to get better), than did patients with inflammatory LBP (P < 0.01). Patients with inflammatory LBP, in turn, more strongly endorsed organic pain beliefs than did pain-free controls (P < 0.05). Endorsement of organic pain beliefs was associated with catastrophizing. CONCLUSION: Organic pain beliefs are associated with increased catastrophizing in patients with chronic LBP, and addressing these beliefs may help patients to manage their pain and disability. Meanings attributed to inflammatory and noninflammatory diagnostic labels may contribute to the different pain beliefs held by different patient groups.

Pain beliefs and perceived physical disability of patients with chronic low back pain.

Cognitive-behavioural therapy and maintenance of exercise have emerged as major tools in the treatment of patients with chronic low back pain. Patients' beliefs about their problem may influence their uptake of and responses to particular treatment modalities. In particular, we hypothesised that patients' beliefs about the cause and treatment of pain may mediate changes in physical disability following participation in a multidisciplinary pain management programme. A cohort of 84 patients was invited to respond to booklets of self-report questionnaires prior to, immediately after and 3 months following participation in multidisciplinary pain management programmes. Questionnaires addressed subjects' beliefs about the nature and treatment of pain (Pain Beliefs Questionnaire), and their disability (Likert-modified Roland and Morris Disability Questionnaire, Physical Functioning scale of the Short Form-36 Health Survey, and Oswestry Low Back Pain Disability Questionnaire). Patients with chronic low back pain who more strongly endorsed 'organic' concepts about the nature and treatment of pain reported higher levels of physical disability at baseline, and displayed greater reductions in disability following participation in the pain management programmes. Reductions in reported 'organic' pain beliefs were associated with improvements in reported disability. Endorsement of 'psychological' concepts about the nature and treatment of pain was not associated with disability. These findings support a view that patients' beliefs about the nature and treatment of their pain can change during participation in a multidisciplinary pain management programme based on cognitive-behavioural intervention. Modification of these beliefs may be associated with improvements in patients' perceptions of the level of their disability.