OA is a painful joint disease that predominantly affects the elderly. Pain is the primary symptom of OA, and it can present as either intermittent or constant. OA pain mechanisms are complex and have only recently been determined. Both peripheral and central processes are involved in creating the OA pain experience, making targeted therapy problematic. Nociceptive, inflammatory and neuropathic pains are all known to occur in OA, but to varying degrees in a patient- and time-specific manner. A better understanding of these multifactorial components of OA pain will lead to the development of more effective and safer pain treatments.

Background Thumb-base osteoarthritis (OA) is a common cause of pain and disability This study aimed to investigate the associations of musculoskeletal ultrasound OA pathologies with the extent of pain, function, radiographic scores, and muscle strength in symptomatic thumb-base osteoarthritis. Methods This is a cross-sectional study of an ongoing clinical trial with eligibility criteria including thumb-base pain on Visual Analogue Scale (VAS) ≥40 (0 to 100 mm), Functional Index for Hand OA (FIHOA) ≥ 6 (0 to 30) and Kellgren Lawrence (KL) grade ≥ 2. The most symptomatic side was scanned to measure synovitis and osteophyte severity using a 0–3 semi-quantitative score, power Doppler and erosion in binary score. A linear regression model was used for associations of ultrasound findings with VAS pain, FIHOA and hand grip and pinch strength tests after adjusting for age, gender, body mass index, disease duration and KL grade as appropriate. For correlation of ultrasound features with KL grade, OARSI ((Osteoarthritis Research Society International) osteophyte and JSN scores, Eaton grades, Spearman coefficients were calculated, and a significant test defined as a p -value less than 0.05. Results The study included 93 participants (mean age of 67.04 years, 78.5% females). Presence of power Doppler has a significant association with VAS pain [adjusted β coefficient = 11.29, P = 0.02] while other ultrasound pathologies revealed no significant associations with all clinical outcomes. In comparison to radiograph, ultrasonographic osteophyte score was significantly associated with KL grade [r s = 0.44 ( P < 0.001)], OARSI osteophyte grade [r s = 0.35 ( P = 0.001)], OARSI JSN grade [r s = 0.43 (P < 0.001)] and Eaton grade [r s = 0.30 ( P < 0.01)]. Ultrasonographic erosion was significantly related with radiographic erosion [r s = − 0.49 (P = 0.001)]. Conclusion From a clinical perspective the significant relationship of power Doppler with pain severity in thumb base OA suggests this might be a useful tool in understanding pain aetiology. It is important to recognise that power Doppler activity was only detected in 14% of the study so this might be an important subgroup of persons to monitor more closely. Trial registration Registered at Australian New Zealand Clinical Trials Registry (ANZCTR), http://www.anzctr.org.au/ , ACTRN12616000353493.

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Background The Patient Activation Measure (PAM-13) was developed using Rasch analysis to assess knowledge, skills and confidence in the management of one’s health. Previous studies report positive relationships between PAM-13 scores, self-management behaviours and longitudinal health outcomes in adults with chronic disease. There is little extant measurement property evidence for the use of PAM-13 in specific osteoarthritis (OA) populations. This study tested measurement properties of the PAM-13 in people living with hip and knee OA. Methods Item response frequency analysis was conducted. Rasch analysis evaluated the fit of the PAM-13 data to the Rasch model. Model-data fit was evaluated using infit and outfit statistics; person/item reliability and person separation indices were computed. Unidimensionality was evaluated using Principal Components Analysis of Rasch residuals and the data were assessed for item redundancy. Differential Item Functioning (DIF) examined bias in respondent subgroups and correlations tested relationships between PAM-13 and other patient-reported outcomes. Results Two-hundred-and-seventeen PAM-13 surveys were completed; there were no missing responses, floor or ceiling effects. Person and item reliability were acceptable (0.98 and 0.87 respectively) with good separation (person separation index 2.58). Unidimensionality was evaluated, with 49.4% of the variance explained by the first eigenvector. There was evidence of potential local response-dependence. The Rasch fit statistics were acceptable (except for item-2). There were some issues identified with targeting of the PAM-13 items to people with higher ability and the item difficulty order was different to that proposed in original cohorts. Significant DIF was identified for sex and educational level for a small number of items. PAM-13 scores were moderately correlated with depressive symptoms on the Depression Anxiety Stress Scale and Assessment of Quality of Life-6D. There were small correlations between PAM-13 and Knee injury and Osteoarthritis Outcome Score pain and activities of daily living scores. Conclusions This study provides some evidence of adequate person and item reliability, unidimensionality, and construct validity to support the use of PAM-13 to measure patient activation in people living with hip and knee OA. Possible limitations regarding targeting, different item difficulty order, DIF and local response dependence should be investigated in future research.

IntroductionKnee osteoarthritis (KOA) is a highly prevalent disabling joint disease. Intra-articular stem cell therapy is increasingly being used for treating KOA with little high-quality evidence to support its use. The aim of this study is to investigate the efficacy, safety and cost-effectiveness of allogeneic mesenchymal stem cells (Cymerus MSCs) for treating symptomatic tibiofemoral KOA and improving knee structure over 24 months.Methods and analysisThe Stem Cell injections for symptomatic relief and strUctural improvement in people with Tibiofemoral knee OsteoaRthritis study is a phase III, multi-centre, parallel, superiority, randomised, double-blind, placebo-controlled trial, which will be conducted in Sydney and Hobart, Australia. 440 participants (220 per arm) aged over 40 years with painful KOA and mild to moderate structural change on X-ray (Kellgren and Lawrence grade 2 or 3) with medial minimum joint space width between 1 and 4 mm in the study knee will be recruited from the community and randomly allocated to receive either intra-articular MSCs or saline at baseline, week 3 and week 52. The coprimary outcomes will be the proportion of participants achieving patient-acceptable symptom state for knee pain at 24 months and quantitative central medial femorotibial compartment cartilage thickness change from baseline to 24 months. Main secondary outcomes include change in knee pain, Patient Global Assessment, physical function, quality of life and other structural changes. Additional data for cost-effectiveness analysis will also be recorded. Adverse events will be monitored throughout the study. The primary analysis will be conducted using modified intention-to-treat.Ethics and disseminationThis protocol has been approved by The University of Sydney (USYD) Human Research Ethics Committee (HREC) #: 2020/119 and The University of Tasmania (UTAS) HREC #: H0021868. All participants will be required to provide informed consent. Dissemination will occur through conferences, social media, and scientific publications.Trial registration numbersAustralian New Zealand Clinical Trials Registry (ACTRN12620000870954); U1111-1234-4897.

The role of skeletal muscle in the pathophysiology of knee OA is poorly understood. To date, the majority of literature has focused on the association of muscle strength with OA symptoms, disease onset and progression. However, deficits or improvements in skeletal muscle strength do not fully explain the mechanisms behind outcome measures in knee OA, such as pain, function and structural disease. This review aims to summarize components of skeletal muscle, providing a holistic view of skeletal muscle mechanisms that includes muscle function, quality and composition and their interactions. Similarly, the role of skeletal muscle in the management of knee OA will be discussed.

Objective To test the effectiveness of a 32‐week, stepped‐care intervention on disease remission rates in overweight and obese patients with medial tibiofemoral osteoarthritis (OA) compared to controls. Methods In this randomized controlled trial, eligible participants were ≥50 years of age with a body mass index of ≥28 kg/m2 and radiographic evidence of medial tibiofemoral OA. Participants were randomized to stepped‐care (n = 87) or control group (n = 84). The stepped‐care group received a 2‐step intervention. The first step consisted of an 18‐week diet and exercise program. The second step consisted of 4 treatment subgroups: 1) diet and exercise maintenance; 2) cognitive–behavioral therapy; 3) unloader knee brace; and 4) muscle strengthening exercises. Allocation into subgroups was based on disease remission state and clinical characteristics. The primary end point was the disease remission rate (yes/no) at 32 weeks, which was reached when participants achieved the Patient Acceptable Symptom State cutoff value for pain and for the patient global assessment of disease activity and/or functional impairment. Results Disease remission at 32 weeks was achieved by 18 of 68 (26%) in the control group and 32 of 82 (39%) in the stepped‐care group (difference 12.6% [95% confidence interval –2.3, 27.4], P = 0.10). The stepped‐care group showed an improvement in pain and function between baseline and 20 weeks. While functional improvement was maintained at 32 weeks, pain levels tended to get worse between weeks 20 and 32. Conclusion The proposed intervention did not promote a significant difference in the rate of disease remission in comparison to the control group for overweight or obese patients with medial tibiofemoral OA.

Objective.To evaluate the association of sleep quality, sleep duration, and fatigue with hip pain exacerbations in persons with symptomatic hip osteoarthritis (OA).Methods.Participants (n = 252) were followed for 90 days and asked to complete online questionnaires at 10-day intervals (control periods). A hip pain exacerbation (case periods) was defined as an increase of 2 points in pain intensity compared with baseline on a numeric rating scale (0–10). Subjective sleep quality and sleep duration were assessed using the Pittsburgh Sleep Quality Index, and fatigue was measured by Multidimensional Assessment of Fatigue in both periods. Univariable and multivariable conditional logistic regressions were used to assess the association.Results.Of the 252 participants, 130 (52%) were included in the final analysis. Univariate association analysis showed that both poor sleep quality and greater fatigue were associated with increased odds of pain exacerbations (OR 1.72, 95% CI 1.04–2.86; OR 1.92, 95% CI 1.21–3.05, respectively). Short sleep duration was not associated with pain exacerbations. Poor sleep quality and greater fatigue remained associated with pain exacerbations after adjustment for physical activity and night pain levels in multivariable analysis. There was no significant interaction between sleep quality and fatigue (p = 0.21).Conclusion.Poor sleep quality and greater fatigue were related to pain exacerbation in persons with symptomatic hip OA. Sleep disorders and fatigue should be considered when dealing with pain exacerbations.