The metatarsophalangeal joints (MTPJs) are the most common location for synovitis in people with rheumatoid arthritis (RA), yet their association with plantar foot pressures has received very little attention. This study aimed to determine whether plantar pressures differed based on sonographic evidence of MTPJ synovitis in people with RA.

Ultrasound was used to assess synovitis (grey scale synovial hypertrophy and power Doppler signal) in MTPJs 1 to 5 using the combined EULAR/Outcome Measures in Rheumatology scoring system. Peak pressure (PP) and pressure time integrals (PTIs) were assessed during barefoot walking for seven plantar foot regions (heel, midfoot, first metatarsal, second metatarsal, third to fifth metatarsals, hallux, lesser toes). Mixed-effects linear regression was used to determine the difference in PP and PTI between MTPJs with none/minimal synovitis and MTPJs with moderate/severe synovitis.

Thirty-five participants with RA were included. Mean age was 66.3 years and mean disease duration was 22.2 years. Participants with sonographic evidence of moderate/severe synovitis at the first MTPJ had reduced PTI at the hallux compared with those with none/minimal synovitis at this joint (P = 0.039). Participants with moderate/severe synovitis at the second MTPJ and fourth MTPJ had reduced PP and reduced PTI at lesser toes compared with those with none/minimal synovitis in these joints (all P ≤ 0.048). No significant differences were observed for synovitis in other joints.

These findings may be suggestive of an inverse relationship between plantar pressure and soft tissue pathology, which is consistent with an offloading strategy and reduced use of the toes during propulsion.

To explore the correlation between the ultrasound-detected synovitis in each individual joint at metacarpophalangeal (MCP), proximal interphalangeal (PIP), and metatarsophalangeal (MTP) regions and the clinical disease activity in patients with rheumatoid arthritis (RA).

Clinical disease activity was assessed by disease activity score (DAS) based on 28-joint count and erythrocyte sedimentation rate (DAS28-ESR), C-reactive protein (DAS28-CRP), Simplified Disease Activity Index (SDAI), and Clinical Disease Activity Index (CDAI). Gray scale (GS) and power Doppler (PD) synovitis was assessed by ultrasound semi-quantitatively. The correlation between clinical disease activity indices and synovitis score in each joint was assessed using Spearman's rank correlation test.

211 RA patients were included in this study. The whole GS scores of all MCP joints showed the highest correlation with each Clinical Disease Activity Index (r = 0.403-0.452, p < 0.01). Likewise, the whole PD scores of all MCP joints also showed the highest correlation with clinical disease activity (r = 0.332-0.396, p < 0.01). At individual joint level, the highest correlation of GS score with DAS28-ESR (r = 0.411, p < 0.01), DAS28-CRP (r = 0.459, p < 0.01), and SDAI (r = 0.444, p < 0.01) was observed in MCP3 joint while with CDAI (r = 0.421, p < 0.01) in MCP2 joint. The highest correlation of PD score with DAS28-ESR (r = 0.353, p < 0.01), DAS28-CRP (r = 0.399, p < 0.01), CDAI (r = 0.368, p < 0.01), and SDAI (r = 0.377, p < 0.01) was observed in MCP5 joint.

The ultrasound-detected synovitis at MCP joints, especially MCP2, MCP3, and MCP5 joints, was best correlated with clinical disease activity in most RA cases, in contrast to PIP and MTP joints. Key Points • The correlation of ultrasound-detected synovitis in each individual joint with the clinical disease activity in RA patients is diverse among joint regions. MCP joints showed the best, in contrast to PIP and MTP joints.

The aim of this scoping review was to investigate ultrasound imaging (USI) acquisition procedures and guidelines used to assess the first metatarsophalangeal joint (MTPJ). MEDLINE, CINAHL, AMED and SPORTDiscus were systematically searched in May 2021. Studies were included if they used grey-scale USI or power Doppler and reported a USI procedure to assess the first MTPJ. Screening and data extraction were performed by two independent assessors. The scoping review was reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses extension for scoping reviews (PRISMA-ScR). A total of 403 citations were identified for screening, with 36 articles included in the final analysis. There was wide variation in USI acquisition procedures used to evaluate the first MTPJ. Inconsistencies in reporting may be attributable to the number of elements the USI acquisition procedure encompasses, which include the model of the USI device, the type of transducer, USI modalities and settings, patient position, transducer orientation, surfaces scanned and the scanning technique used. The review found inconsistencies against international guidelines and limited implementation of consensus-based recommendations to guide image acquisition. Current guidelines require further refinement of anatomical reference points to establish a standardised USI acquisition procedure, subsequently improving interpretability and reproducibility between USI studies that evaluate the first MTPJ.

To investigate the agreement between clinical signs (tenderness and/or swelling) in ankles and feet joints and ultrasound findings in patients with rheumatoid arthritis (RA).

RA patients with at least 1 tender and/or swollen joint in bilateral ankles and metatarsophalangeal (MTP) joints detected by physical examination were enrolled and underwent ultrasound examination by greyscale (GS) and power Doppler (PD) mode. The agreement between clinical signs and ultrasound-detected inflammation (joint effusion, synovitis, or tenosynovitis) was analyzed.

In the study, 113 consecutive RA patients were included, with mean age of (52.5±12.6) years, median duration of 60 (13, 129) months, mean disease activity score in 28 joints based on erythrocyte sedimentation rate [DAS28 (ESR)] of 5.1±1.7, mean disease activity score in 28 joints based on C reactive protein[DAS28 (CRP)]of 4.6±1.5. The tenderness and swelling was most commonly detected in ankles (52.7% and 31.9%, respectively), while GS (+) synovitis was most frequently detectable in MTP2 (34.1%), followed by ankles (32.7%) and MTP1 (27.9%), and PD (+) synovitis was most frequently detectable in MTP1 (14.2%), followed by ankles (12.4%) and MTP2 (10.6%). The prevalence of tenosynovitis was 41.1%, which mostly located in tibialis posterior tendon (22.1% of GS positive and 17.6% of PD positive). The highest prevalence of joint effusion was detected in ankles (9.7%), while that of bone erosion in MTP5 (19%). The overall concordance rate between positive clinical signs and ultrasound-determined joint inflammation was poor in the above joints (κ < 0.2, P < 0.05), in which swelling had the highest κ coefficient with ultrasound-determined joint inflammation in ankles (κ=0.225, P < 0.05). Moreover, swelling had the highest κ coefficient with synovitis in ankles (κ=0.231, P < 0.05).The concordance between tenosynovitis and signs in ankles was also poor (κ < 0.20, P < 0.05). There was no significant agreement between joint effusion and clinical signs (P > 0.05).

The overall concordance between clinical signs and inflammation on ultrasound was poor in ankles and feet joints. Tenderness and swelling was more common in ankles, while more lesions were detected by ultrasound at MTP joints. Ultrasound is useful in assessing the lesions besides physical examination in patients with RA.

In rheumatoid arthritis, forefoot disease activity can lead to joint damage, pain, and disability during weight-bearing activities; therefore, the evaluation and control of forefoot disease activity is important. We aimed to investigate an association between the prevalence of abnormalities in the forefoot based on ultrasonography (US) and the clinical and US findings related to arthritis and identify factors related to the presence of synovitis in the forefoot of RA patients.

In total, 810 metatarsophalangeal joints of 81 rheumatoid arthritis patients were examined using US. Patients were assigned to either a forefoot synovitis group (n = 22), with foot synovitis detected using US, or a non-forefoot synovitis group (n = 59). We assessed associations between clinical parameters and US finding of the hand and US finding of the metatarsophalangeal joints.

The following were significantly higher in forefoot synovitis group than in non-forefoot synovitis group: swollen joint count [P < 0.001]; Disease Activity Score 28 based on C-reactive protein [P < 0.05]; clinical disease activity index [P < 0.001]; and total Power Doppler score of the hand [P < 0.001]. Receiver-operating characteristic analysis for total Power Doppler scores of the hand to suggest the presence of synovitis in the metatarsophalangeal joints showed that a total Power Doppler score of the hand of ≥5 was associated with synovitis in the metatarsophalangeal joints, with a sensitivity of 68% and a specificity of 85% (odds ratio = 11.9).

Total Power Doppler scores of the hand had a good valuable score for suggesting the presence of synovitis in metatarsophalangeal joints of rheumatoid arthritis patients.

Rheumatoid arthritis (RA) is a systemic autoimmune disease that has a great impact on different joints, may result in their destruction and loss of function. Although the shoulder is affected in a large portion of patients with RA, it does not receive much attention during the follow up of RA. The precise diagnosis of shoulder pain in RA is a clinical challenge and benefits from a reliable imaging modality to detect its exact origin.

To determine the diagnostic accuracy of ultrasound (US) in detecting shoulder joint pathologies in RA, considering magnetic resonance imaging (MRI) as the gold standard.

This cross-sectional, observational study was carried out on 30 RA patients complaining of unilateral or bilateral shoulder pain. Patients were subjected to history taking, clinical shoulder examination, plain X-ray, US examination following a standardized protocol, and MRI. The results were correlated with each other.

In comparison with the MRI findings, US showed high accuracy in terms of sensitivity (Sn) and specificity (Sp) in supraspinatus tendinopathy (Sn 96.6%; Sp 93.3%), biceps tenosynovitis (Sn 87.5%; Sp 97.6%), subacromial-subdeltoid bursitis (Sn 72.7%; Sp 95.7%), humeral erosions (Sn 90.5%; Sp 97.3%), and acromioclavicular osteoarthritis (Sn 85.7%; Sp 95.7%). In terms of reliability, the agreement between US and MRI was almost perfect (κ = .9, P < .001).

US may have a role as the initial imaging modality in RA patients with shoulder pain, as it is highly sensitive and specific in detecting different pathological abnormalities of the shoulder.

Joint swelling and tenderness are considered a proxy for inflammation in patients with rheumatoid arthritis (RA). With ultrasound-detected inflammation as reference, our objectives were to explore on patient and joint level the associations between ultrasound synovitis and joint swelling, tenderness and patient-reported joint pain (PRJP).

209 patients with established RA were examined six times during 12 months with assessment of 32 joints in upper/lower extremities for joint swelling/tenderness and Grey scale (GS)/power Doppler (PD) synovitis. PRJP was assessed on a manikin. Correlations between different sum scores were at each examination calculated using Spearman's rho (r), agreement at joint level was examined by Cohen's kappa and logistic regression models were used to explore the associations between joint assessment and GS/PD scores.

At patient level, swollen joints were strongly correlated with GS/PD sum scores (r=0.64-0.88), while tender joints were primarily associated with PRJP (r=0.54-0.68). At joint level, GS/PD pathology had higher agreement with swelling (kappa 0.54-0.57) than tenderness (kappa 0.20-0.21) or PRJP (0.23-0.25). Higher percentages of joints were swollen according to increasing GS/PD scores, independently of joint tenderness. However, joints being tender, but not swollen, were not associated with GS/PD scores. Receiver operating curves showed swollen but not tender joints to be associated with GS/PD scores.

Swollen joints were strongly associated with ultrasound detected synovitis at both patient and joint level, while this association was not found for tender joints. These results may question if tender joints reflect ongoing inflammation in established RA.

To describe the dorsal 4-finger technique (DFFT) in examining metacarpophalangeal (MCP) joints of patients with rheumatoid arthritis (RA) and compare it to the traditional 2-finger technique (TFT) using ultrasound (US) as a gold standard.

Four rheumatologists evaluated 180 MCP joints of 18 patients with RA. All patients underwent US for greyscale (GSUS) and power Doppler US (PDUS). Agreements between rheumatologists, the 2 techniques, and US were evaluated using Cohen κ and the first-order agreement coefficient (AC1) κ methods.

The population comprised 17 females (94.4%) with a mean (SD) age and disease duration of 56.8 (14.4) and 21.8 (12.9) years, respectively. Eight patients (44.4%) were taking methotrexate monotherapy, while 10 patients (55.6%) were receiving biologics. US evaluation revealed 69 (38.3%) and 30 (16.7%) joints exhibited synovitis grade 2-3 by GSUS and PDUS, respectively. Effusion was documented in 30 joints (16.7%). The mean intraobserver agreement using the DFFT and TFT were 80.5% and 86%, respectively. The mean interobserver agreements using the DFFT and TFT were 84% and 74%, respectively. κ agreement with US findings was similar for both techniques in tender joints but was higher for the DFFT in nontender joints (0.33 vs 0.07, p = 0.015 for GSUS) and (0.48 vs 0.11, p = 0.002 for PDUS). The DFFT had a higher sensitivity in detecting ballottement by GSUS (0.47 vs 0.2, p < 0.001) and PDUS (0.60 vs 0.27, p < 0.001).

The DFFT is a novel, reproducible, and reliable method to examine MCP joints, and it has a better correlation with US than the traditional TFT.

For over a decade, a large number of studies have highlighted the benefits of ultrasound (US) in the diagnosis and management of rheumatic diseases, especially rheumatoid arthritis (RA). However, its benefits in routine practice have been less studied and trials examining US as part of various clinical strategies are just emerging, with recent randomised trials examining the added value of US in tight-control paradigms. The conclusions of these trials have raised questions on the role of US in RA management. This Viewpoint analyses the recent studies, and discusses potential limitations in study designs as well as the methodological challenges of assessing the added value of an imaging technique.

To develop evidence-based recommendations on the use of ultrasound (US) and magnetic resonance imaging (MRI) in patients with rheumatoid arthritis (RA).

Recommendations were generated following a nominal group technique. A panel of experts, consisting of 15 rheumatologists and 3 radiologists, was established in the first panel meeting to define the scope and purpose of the consensus document, as well as chapters, potential recommendations and systematic literature reviews (we used and updated those from previous EULAR documents). A first draft of recommendations and text was generated. Then, an electronic Delphi process (2 rounds) was carried out. Recommendations were voted from 1 (total disagreement) to 10 (total agreement). We defined agreement if at least 70% of experts voted ≥7. The level of evidence and grade or recommendation was assessed using the Oxford Centre for Evidence-based Medicine Levels of Evidence. The full text was circulated and reviewed by the panel. The consensus was coordinated by an expert methodologist.

A total of 20 recommendations were proposed. They include the validity of US and MRI regarding inflammation and damage detection, diagnosis, prediction (structural damage progression, flare, treatment response, etc.), monitoring and the use of US guided injections/biopsies.

These recommendations will help clinicians use US and MRI in RA patients.

Cytokines have an important role in the pathogenesis of rheumatoid arthritis (RA). Although plasma levels of IL-6 have been related to musculoskeletal ultrasound (MSUS) synovitis in early DMARD-naïve RA, there are no similar studies in established disease.

64 RA patients treated with non-biological DMARDs and 30 healthy controls were included in this prospective cross-sectional study. A blood sample was taken before evaluation of disease activity (DAS28) and ultrasonography (all tests performed in a blinded fashion). MSUS was performed by one of two ultrasound-trained rheumatologists on 10 joints of both hands. Gray scale (GS) and pD (power Doppler) synovitis were evaluated using a semi-quantitative scale (0-3) in individual joints, and their sum (score 10) was calculated. Plasma cytokines (IL-2, IL-4, IL-6, IL-10, IL-17, TNF, IFN-γ, and VEGF) were quantified by flow cytometry.

Levels of all cytokines, excepting VEGF, were significantly higher in RA patients than in controls (P⩽0.05). In RA patients, IL-6, but not other cytokines, correlated positively with DAS28 and swollen joint count (P⩽0.01), as well as with 10-joint pD score, and GS and pD of both wrists (P<0.01 for all tests). In multiple linear regression, the association of IL-6 with 10-joint pD score was maintained even after adjustment for DAS28. However, there was no correlation of IL-6 with tender joint count, 10-joint GS score, or presence of erosions.

We demonstrated an association of inflammatory findings on MSUS and plasma IL-6 independently of DAS28 in established RA.

Assessment of synovitis in the metatarsophalangeal (MTP) joints with ultrasound has been shown to improve the accuracy of assessment of rheumatoid arthritis (RA). However, the presence of intraarticular low-echoic synovial area (LESA) in the MTP joints in healthy subjects complicates the sonographic assessment of these joints.

Healthy subjects with no arthritic symptoms in their MTP joints were recruited. All subjects completed a questionnaire and underwent physical examination and sonographic assessment. LESAs in the dorsal aspect of all MTP joints were measured in the longitudinal view.

One thousand non-arthritic MTP joints in 100 healthy subjects (female 73, mean age 41.0 years old) were evaluated. Measurable LESAs were identified in all joints assessed. Mean length of LESA in each of the 1st-5th MTP joints was 17.8, 13.9, 11.9, 10.6, and 9.2 mm, respectively, whereas mean thickness was 2.4, 2.4, 1.8, 1.2, and 0.8 mm, respectively. Multivariate linear regression models identified the difference between 1st and 5th MTP joints as the most independently influential factor on the measurement of LESA.

Our data provide the normal reference values for the measurements of LESA in Japanese, which should be taken into consideration when the synovitis in MTP joints is evaluated with ultrasound.

Remission is the ultimate goal of the treatment of rheumatoid arthritis (RA). However, the diagnosis of remission might still be vague. Musculoskeletal ultrasound (US) seems to effectively assess synovitis, effusion and bone damage. Thus, its role could be relevant for the diagnosis, monitoring or detection of relapse in the follow-up of RA in remission. The goal of this review of the literature was to clarify the added value of ultrasonography during remission.

A systemic search of the literature was performed on Medline and Scopus. The following key words were used: rheumatoid arthritis, remission, US. Fifty-six papers were collected, then after an in depth analysis, twelve articles were selected for analysis.

Twelve papers were identified that assessed remission in RA. Remission criteria varied from one author to another. The number of joints assessed by US varied from six to 44 with the wrist and metacarpo-phalangeal joints of the dominant hand scanned at least. Irrespective of remission criteria, all authors demonstrated that US detected Doppler positive synovitis in patients in clinical remission. Also, power Doppler synovitis predicted structural damage and future flares of RA.

US seems to be more effective than a clinical exam. True remission in RA must be defined. Moreover, the inclusion of this technique in the new definition of remission is being validated.

In practice, composite indices are used for rheumatoid arthritis (RA) disease activity evaluation. Despite valid and widely used, not rarely composite indices miss accuracy. Ultrasound (US) is more precise than clinical examination in synovitis appraisal. US-based disease activity estimation depends on the detection of synovitis. The most common synovitis abnormalities are proliferation, effusion, and neoangiogenesis. Gray scale ultrasound identifies synovial hypertrophy and effusion with its good soft tissue contrast. Additionally, power Doppler ultrasound depicts neoangiogenesis within synovia, remarking local inflammation. Several studies have combined local US findings to develop a patient level disease activity index. Most of them summed selected joint scores in an overall score of disease activity and evaluated its correlation with clinical composite indexes. To be incorporated into clinical practice, an overall US score must have some fundamental characteristics such as reproducibility, viability, and sensitivity to change over time. In global US score development, finding the joints that truly estimate individual disease activity is highly challenging. This article presents an up-to-date literature review on assessing RA disease activity with US and depicts the challenges in finding the perfect global US score.