Corrigendum to "Study protocol for the follow-up examination of the Nor-Hand study: A hospital-based observational cohort study exploring pain and biomarkers in people with hand osteoarthritis" [Osteoarthr. Cartil. Open 3 (2021) 100198].

[This corrects the article DOI: 10.1016/j.ocarto.2021.100198.].

Study protocol for the follow-up examination of the Nor-Hand study: A hospital-based observational cohort study exploring pain and biomarkers in people with hand osteoarthritis.

Objective: This study aims to increase the understanding of pain mechanisms in hand OA and explore potential risk factors for pain development or worsening in a biopsychosocial framework. Another important aim is to validate potential soluble and imaging OA biomarkers. Design: The follow-up examination of the Nor-Hand hospital-based observational cohort study started in October 2019 and was completed in May 2021. In total, 212 of the 300 participants with hand OA who were examined at baseline attended the follow-up study. The participants underwent clinical joint examinations, medical and functional assessments, quantitative sensory testing, fluorescence optical imaging, ultrasound of the hands, acromioclavicular joints, feet, knees and hips, conventional radiographs of the hands and feet and magnetic resonance imaging of the dominant hand. Blood and urine samples were collected, and all participants answered questions about demographic factors and OA-related questionnaires. Associations between disease variables and symptoms will be examined in cross-sectional and longitudinal analyses. Longitudinal analyses will be performed to assess the predictive value of baseline variables on hand OA outcomes. Conclusion: Current knowledge about predictors for disease progression in hand OA is limited, but with longitudinal data we will be able to explore the predictive value of baseline variables on hand OA outcomes, such as changes in patient-reported outcomes or changes in soluble and imaging biomarkers. This provides a unique opportunity to gain more knowledge about the natural disease course of hand OA.

A hospital-based observational cohort study exploring pain and biomarkers in patients with hand osteoarthritis in Norway: The Nor-Hand protocol.

INTRODUCTION: We have limited knowledge about the underlying disease mechanisms and causes of pain in hand osteoarthritis (OA). Consequently, no disease-modifying drug exists, and more knowledge about the pathogenesis of hand OA is needed, as well as a validation of different outcome measures. Our first aim of this study is to explore the validity of various imaging modalities for the assessment of hand OA. Second, we want to gain a better understanding of the disease processes, with a special focus on pain mechanisms. METHODS AND ANALYSIS: The Nor-Hand study is a hospital-based observational study including 300 patients with evidence of hand OA by ultrasound and/or clinical examination. The baseline examination consists of functional tests and joint assessment of the hands, medical assessment, pain sensitisation tests, ultrasound (hands, acromioclavicular joint, hips, knees and feet), CT and MRI of the dominant hand, conventional radiographs of the hands and feet, fluorescence optical imaging of the hands, collection of blood and urine samples as well as self-reported demographic factors and OA-related questionnaires. Two follow-up examinations are planned. Cross-sectional analyses will be used to investigate agreements and associations between different relevant measures at the baseline examination, whereas the longitudinal data will be used for evaluation of predictors for clinical outcomes. ETHICS AND DISSEMINATION: The protocol is approved by the Norwegian Regional Committee for Medical and Health Research Ethics (Ref. no: 2014/2057). The participants receive oral and written information about the project and sign a consent form before participation. They can, whenever they want, withdraw from the study, and all de-identified data will be safely stored on the research server at Diakonhjemmet Hospital. Results will be presented at international and national congresses and in peer-reviewed rheumatology journals. TRIAL REGISTRATION NUMBER: NCT03083548; Pre-results.

The comparison of magnetic resonance imaging and radiographs to assess structural progression over 5 years in hand osteoarthritis.

Objective: . The aim was to explore the agreement between 1.0 T MRI and conventional radiography (CR) to detect progression of hand OA over 5 years and the associations between structural progression and incident joint tenderness. Methods: Paired radiographs and paired MRIs of the second-fifth IP joints of the dominant hand from 69 hand OA patients were read for osteophytes, joint space narrowing and erosions. Patients with two or more joints demonstrating progression of any structural feature(s) were classified as progressors per imaging modality. Agreement between methods to detect progressors was evaluated with κ and intraclass correlation coefficients. At the joint level, the associations between methods to detect progression were explored with generalized estimating equations. Likewise, we analysed the associations between progression per imaging modality and incident pain. Results: MRI (58.0%) and CR (62.3%) detected similar numbers of progressors. The agreement between methods to detect progressors was good (κ = 0.61). We found good agreement between methods regarding the number of progressive joints (intraclass correlation coefficient = 0.61, 95% CI: 0.43, 0.76). At the joint level, MRI progression was associated with radiographic progression (P < 0.001). Incident joint tenderness was more common in joints with progression by MRI and CR, but statistically significance was not reached. Conclusion: Both 1.0 T MRI and CR detect a similar amount of progression over 5 years in patients with hand OA, although not in exactly the same joints. As CR assesses more joints for a lower cost, CR should be the imaging modality of choice rather than 1.0 T MRI in observational studies with a long period of follow-up.

Reduced hemithoracic uptake on 99mTc-MDP bone scintigraphy: an underrecognized sign of massive pleural effusion--a case report.

The uptake of (99m)Tc-methylene diphosphonate (MDP) in malignant pleural effusions and, rarely, in nonmalignant pleural effusions has been well documented in the literature. Although the exact mechanism of uptake in these conditions remains unclear, there have been attempts to use the bone scintigraphic features of pleural effusion to predict sensitivity and specificity for malignancy based on pleural fluid cytology. It has been suggested that activity in the chest increases with an increase in effusion volume. We report here, however, a case of malignant pleural effusion, that showed reduced hemithoracic activity in contrast to the expected increased activity. Our experience highlights the need for an open and inquisitive mind to avoid diagnostic pitfalls when confronted with a bone scintigram showing reduced uptake unilaterally or bilaterally in the chest.