Imaging Evaluation of the Entheses

Ultrasonographic study of the thumb pulleys and their entheses: correlations with anatomy and histology

OBJECTIVES

The entheseal nature of digital annular pulleys insertion was recently described, with high resolution ultrasound (US) reliably identifying these submillimetre structures with impressive accuracy. Since the thumb was not examined, the aim of the present study was to characterise the thumb annular pulley system, including entheses, from an anatomical, histological and ultrasonographic perspective.

METHODS

US assessment and gross anatomical dissection were performed on cadaveric thumbs to investigate the thickness and structural features of the four thumb pulleys, including the identification of their entheses. US and anatomical measurements were correlated. Entheses identified by US were verified by histology. All thumb pulleys in healthy controls (HC) were detected and thickness was measured by US. A reliability exercise on US identification and anatomical study of thumb pulleys was carried out.

RESULTS

20 cadaveric thumbs and 40 thumbs from HC were examined. A total of 240 thumb pulleys (80 cadaveric, 160 HC) were analysed. The cadaveric study demonstrated good correlation between anatomical and US measurement of thumb pulleys thickness (r=0.8). Histology confirmed the entheseal nature of thumb pulleys insertions, with both fibrous and fibrocartilaginous features. 267/480 (55.6%) entheses were detected by US. A1 pulley entheses were always visualised while oblique pulley and A2 pulley entheses were seldom identified. The intrarater and inter-rater reliability showed good correlation among participants.

CONCLUSIONS

US is an effective and reliable tool to detect and study thumb pulleys, even though the identification of their entheses may be challenging and require advanced US skills.

Peripheral Spondyloarthritis: Conceptualization and Diagnosis as a Distinct Rheumatologic Subset of Disease

Peripheral spondyloarthritis (pSpA) encompasses multiple entities affecting the musculoskeletal system with classic findings of synovitis, enthesitis, and tenosynovitis. It remains poorly defined when compared with the axial spondyloarthritides due to nonspecific symptoms, ill-defined imaging findings, and lack of specific testable biomarkers. Previous research has tried to distinguish between the two disease entities using clinical presentations, scoring systems, and radiographic findings; however, overlap remains. We summarize the current classification of pSpA, imaging findings, and the distinction between these entities and axial spondyloarthritis.

Relationship Between Ultrasound and Physical Examination in the Assessment of Enthesitis in Patients With Spondyloarthritis: Results From the DEUS Multicenter Study

OBJECTIVE

The study objectives were (i) to explore the agreement between the Outcome Measures in Rheumatology (OMERACT) ultrasound lesions of enthesitis and physical examination in assessing enthesitis in patients with spondyloarthritis (SpA) and (ii) to investigate the prevalence and clinical relevance of subclinical enthesitis in this population.

METHODS

Twenty rheumatology centers participated in this cross-sectional study. Patients with SpA, including axial spondyloarthritis (axSpA) and psoriatic arthritis (PsA), underwent both ultrasound scan and physical examination of large lower limb entheses. The OMERACT ultrasound lesions of enthesitis were considered, along with a recently proposed definition for "active enthesitis" by our group. Subclinical enthesitis was defined as the presence of "active enthesitis" in ≥1 enthesis in patients with SpA without clinical enthesitis (ie, number of positive entheses on physical examination and Leeds Enthesitis Index score = 0).

RESULTS

A total of 4,130 entheses in 413 patients with SpA (224 with axSpA and 189 with PsA) were evaluated through ultrasound and physical examination. Agreement between ultrasound and physical examination ranged from moderate (ie, enthesophytes) to almost perfect (ie, power Doppler and "active enthesitis"). Patellar tendon entheses demonstrated the highest agreement, whereas Achilles tendon insertion showed the lowest. Among 158 (38.3%) of 413 patients with SpA with clinical enthesitis, 108 (68.4%) exhibited no "active enthesitis" on ultrasound. Conversely, of those 255 without clinical enthesitis, 39 (15.3%) showed subclinical enthesitis. Subclinical enthesitis was strongly associated with local structural damage. However, no differences were observed regarding the demographic and clinical profiles of patients with SpA with and without subclinical enthesitis.

CONCLUSION

Our study underscores the need for a comprehensive tool integrating ultrasound and physical examination for assessing enthesitis in patients with SpA.

Power Doppler signal at the enthesis and bone erosions are the most discriminative OMERACT ultrasound lesions for SpA: results from the DEUS (Defining Enthesitis on Ultrasound in Spondyloarthritis) multicentre study

OBJECTIVES

To assess, in spondyloarthritis (SpA), the discriminative value of the Outcome Measures in Rheumatology (OMERACT) ultrasound lesions of enthesitis and their associations with clinical features in this population.

METHODS

In this multicentre study involving 20 rheumatology centres, clinical and ultrasound examinations of the lower limb large entheses were performed in 413 patients with SpA (axial SpA and psoriatic arthritis) and 282 disease controls (osteoarthritis and fibromyalgia). 'Active enthesitis' was defined as (1) power Doppler (PD) at the enthesis grade ≥1 plus entheseal thickening and/or hypoechoic areas, or (2) PD grade >1 (independent of the presence of entheseal thickening and/or hypoechoic areas).

RESULTS

In the univariate analysis, all OMERACT lesions except enthesophytes/calcifications showed a significant association with SpA. PD (OR=8.77, 95% CI 4.40 to 19.20, p<0.001) and bone erosions (OR=4.75, 95% CI 2.43 to 10.10, p<0.001) retained this association in the multivariate analysis. Among the lower limb entheses, only the Achilles tendon was significantly associated with SpA (OR=1.93, 95% CI 1.30 to 2.88, p<0.001) in the multivariate analyses. Active enthesitis showed a significant association with SpA (OR=9.20, 95% CI 4.21 to 23.20, p<0.001), and unlike the individual OMERACT ultrasound lesions it was consistently associated with most clinical measures of SpA disease activity and severity in the regression analyses.

CONCLUSIONS

This large multicentre study assessed the value of different ultrasound findings of enthesitis in SpA, identifying the most discriminative ultrasound lesions and entheseal sites for SpA. Ultrasound could differentiate between SpA-related enthesitis and other forms of entheseal pathology (ie, mechanical enthesitis), thus improving the assessment of entheseal involvement in SpA.

Ultrasound Assessment of Entheseal Sites and Anterior Chest Wall in Ankylosing Spondylitis: A Cross-Sectional Study

OBJECTIVES

The study was designed to evaluate entheseal sites and anterior chest wall (ACW) of patients with ankylosing spondylitis (AS) using ultrasound (US) and investigate the correlation between disease activity and US score.

METHODS

This prospective cross-sectional study included 104 patients with AS and 50 control subjects. Each patient underwent US scanning of 23 entheses and 11 sites of the ACW. The US features, including hypoechogenicity, thickness, erosion, calcification, bursitis, and Doppler signal, were evaluated. Disease activity was assessed based on C reactive protein (CRP), erythrocyte sedimentation rate (ESR), disease activity score-C reactive protein (ASDAS-CRP), and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI).

RESULTS

The most commonly involved entheses on US were the Achilles tendon (AT) and quadriceps tendon (QT). The most involved site of ACW was the sternoclavicular joint (SCJ). Compared with the control group, significant differences were observed in the AS group in the rates of US enthesitis and ACW in AT (P = .01), SCJ (P = .00), and costochondral joint (CCJ) (P = .01). Patients with high or very high disease activity had a higher erosion score (P = .02). The erosion score was weakly positively associated with CRP, ESR, BASDAI, ASDAS-CRP, and ASDAS-ESR (correlation coefficient: 0.22-0.45).

CONCLUSIONS

The most commonly involved entheseal sites on US were AT and QT, while the site of ACW was SCJ. The US assessment of AS should take the ACW into account. High disease activity might indicate erosion in AS.

Ultrasonography of heel entheses in axial spondyloarthritis patients: frequency and assessment of associated factors

PURPOSE

Foot entheses involvement is a common manifestation of spondyloarthritis. The superiority of ultrasonography examination in foot entheses damages detection has been reported. We aimed to compare the ultrasonography findings of foot entheses between spondyloarthritis patients. and healthy controls and to identify factors associated with enthesitic heel involvement.

METHODS

We conducted a cross-sectional study including 37 patients with axial spondyloarthritis (G1) and 37 healthy subjects matched by age and gender (G0). The following pro-inflammatory cytokines were measured: Interleukin (IL-)1, IL-6, IL-17, and IL-23. A blind ultrasonography of foot entheses was performed to examine calcaneal tendon (CT) and plantar fascia (PF).

RESULTS

The mean age was 44.62 ± 12.31 years. Non-steroidal anti-inflammatory drugs were taken in 92% of patients. Clinical heel enthesopathy was noted in 10 patients (27%) of G1. No participant has enthesitic pain in G0. Ultrasonography changes in CT and PF were more frequent in G1 than G0 (p = 0.001 and p = 10-3, respectively). In the PF, tendon thickening was significantly higher in G1 than G0 (p = 0.03). Power Doppler in both enthesitic sites was exclusively observed in G1 (p = 10-3). Regarding associated factors, CT enthesophytes were less frequent in patients taking non-steroidal anti-inflammatory drugs continuously or having regular physical activity. PF structural damages were associated with higher erythrocyte sedimentation rate (p = 0.02), higher IL-23 level (p = 0.01), and higher disease activity (p = 0.04).

CONCLUSION

Ultrasonography lesions of heel entheses were frequent in spondyloarthritis. Disease activity and inflammatory markers were higher in patients with heel enthesitis. Non-steroidal anti-inflammatory drugs intake and regular physical activity may prevent enthesophytes' occurrence.

A clinical practice guideline for the screening and assessment of enthesitis in patients with spondyloarthritis

OBJECTIVE

The aim of this review is to provide guidance on the selection of approaches to the screening and assessment of enthesitis in patients with spondyloarthritis (SpA).

METHODS

Twenty-four questions regarding the approaches to the screening and assessment of enthesitis and the implementation details were devised, followed by a systemic literature review. The Grading of Recommendations Assessment, Development, and Evaluation methodology was employed in the development of this guideline, with modifications to evaluate non-interventional approaches under comprehensive consideration of costs, accessibility, and evidence strength. A consensus from the voting panel was required for the inclusion of the final recommendations and the strength of each recommendation.

RESULTS

Seventeen recommendations (including five strong recommendations) were included in this guideline. The voting panel expressed unequivocal support for the necessity of screening and assessment of enthesitis in patients with SpA. It was agreed unanimously that symptom evaluation and physical examination should serve as the initial steps to the recognition of enthesitis, whereas Maastricht Ankylosing Spondylitis Enthesitis Score is a reliable tool in both clinical trials and daily medical practice. Ultrasound examination is another reliable tool, with power Doppler ultrasound as an informative addition. Notwithstanding its high resolution, MRI is limited by the costs and relatively low accessibility, whereas radiographs had low sensitivity and therefore should be rendered obsolete in the assessment of enthesitis. PET/CT was strongly opposed in the detection of enthesitis.

CONCLUSION

This guideline provides clinicians with information regarding the screening and assessment of enthesitis in patients with SpA. However, this guideline does not intend on dictating choices, and the ultimate decisions should be made in light of the actual circumstances of the facilities.

Concepts of Entheseal Pain

Pain is the main symptom in entheseal diseases (enthesopathies) despite a paucity of nerve endings in the enthesis itself. Eicosanoids, cytokines, and neuropeptides released during inflammation and repeated nonphysiologic mechanical challenge not only stimulate or sensitize primary afferent neurons present in structures adjacent to the enthesis, but also trigger a "neurovascular invasion" that allows the spreading of nerves and blood vessels into the enthesis. Nociceptive pseudounipolar neurons support this process by releasing neurotransmitters from peripheral endings that induce neovascularization and peripheral pain sensitization. This process may explain the frequently observed dissociation between subjective symptoms such as pain and the structural findings on imaging in entheseal disease.

A Systematic Approach to Diagnosing Arthritis Based on Radiological Imaging

:

Radiology plays key roles in diagnosis of arthritis. We herein suggest an algorithmic approach to diagnosing arthritis. First, the number of joint involvements is reviewed. Monoarticular arthritis includes septic arthritis, pigmented villonodular synovitis, and synovial chondromatosis. Second, polyarticular arthritis can be categorized by its characteristics: erosive, productive and mixed. Erosive disease includes rheumatoid arthritis, hemophilia, and amyloidosis while productive disease includes osteoarthritis, and hemochromatosis. Third, mixed diseases are subcategorized by symmetricity. Ankylosing spondylitis and inflammatory bowel disease related arthritis affect joints symmetrically while psoriatic arthritis, reactive arthritis, and crystalline arthropathy are asymmetric. Adjacent soft tissue density, periostitis, and bone density are ancillary findings that can be used as additional differential diagnostic clues. The final step in identifying the type of arthritis is to check whether the location is a site frequently affected by one particular disease over another. This systematic approach would be helpful for radiologist to diagnose arthritis.

A Narrative Review of the Design of Ultrasound Indices for Detecting Enthesitis

With the increased utilization of musculoskeletal ultrasound in clinical practice, there has been rapid proliferation of publications on sonographic evaluation of enthesitis. This has led to the development of multiple new approaches to scoring sonographic findings in the detection of enthesitis, with variations including entheseal sites and sonographic features that limit cross-study comparisons. Furthermore, despite efforts to standardize the definition of enthesitis, there is still heterogeneity in the sonographic features included in existing ultrasound scores, and additional adjustments are required to distinguish active inflammatory changes from non-inflammatory conditions and to adjust for demographic features associated with increased prevalence of abnormal sonographic findings. This review provides an update on the current landscape of ultrasound scoring systems for enthesitis and emphasizes the importance of future data-based ultrasound scoring systems to improve the distinction between inflammatory and non-inflammatory or degenerative changes of the enthesis.

Assessment of enthesopathy in patients with acne vulgaris: A case-controlled trial

AIM

This case-controlled study aimed at evaluating whether enthesitis is possibly associated with acne vulgaris.

METHODS

This study was carried out on 90 patients with acne vulgaris and 30 normal individuals who were subjected to full history talking, acne scoring system, general, dermatological, musculoskeletal examination, and musculoskeletal ultrasonography with Doppler flow.

RESULTS

A significant relation (P < 0.05) was discovered between left femoral condyle tenderness, which increased left femoral condyle hypoechogenicity on ultrasound. Moreover, a highly significant relation (P < 0.001) was established between tenderness on clinical examination and hypoechogenicity on ultrasound at three sites (right humerus epicondyle, right femoral condyle, and left humerus epicondyle). An association between tenderness and ultrasound increased thickness was significantly reported in the left femoral condyle (P < 0.05). Hypoechogenicity on ultrasound examination was more statistically evident with increased acne severity at the left Achilles tendon (LA), while enthesis calcifications (enthesophytes) were significantly associated with increased acne severity in the left humerus epicondyle (LA) and the right Achilles tendon (RA) (P < 0.05).

CONCLUSION

There is a solid possibility acne is a systemic disease triggering other co-morbidities beyond skin which needs to be fully elucidated by further research evidence.

Lateral epicondylosis: A literature review to link pathology and tendon function to tissue-level treatment and ergonomic interventions

BACKGROUND

Common treatments for lateral epicondylosis (LE) focus on tissue healing. Ergonomic advice is suggested broadly, but recommendations based on biomechanical motion parameters associated with functional activities are rarely made. This review analyzes the role of body functions and activities in LE and integrates the findings to suggest motion parameters applicable to education and interventions relevant to activities and life roles for patients.

PURPOSE

This study examines LE pathology, tendon and muscle biomechanics, and population exposure outlining potentially hazardous activities and integrates those to provide motion parameters for ergonomic interventions to treat or prevent LE. A disease model is discussed to align treatment approaches to the stage of LE tendinopathy.

STUDY DESIGN

Integrative review METHODS: We conducted in-depth searches using PubMed, Medline, and government websites. All levels of evidence were included, and the framework for behavioral research from the National Institutes of Health was used to synthesize ergonomic research.

RESULTS

The review broadened the diagnosis of LE from a tendon ailment to one affecting the enthesis of the capitellum. It reinforced the continuum of severity to encompass degeneration as well as regeneration. Systematic reviews confirmed the availability of evidence for tissue-based treatments, but evidence of well-defined harm reducing occupational interventions was scattered amongst evidence levels. Integration of biomechanical studies and population information gave insight into types of potentially hazardous activities and provided a theoretical basis for limiting hazardous exposures to wrist extensor tendons by reducing force, compression, and shearing during functional activities.

CONCLUSIONS

These findings may broaden the first treatment approach from a passive, watchful waiting into an active exploration and reduction of at-risk activities and motions. Including the findings into education modules may provide patients with the knowledge to lastingly reduce potentially hazardous motions during their daily activities, and researchers to define parameters of ergonomic interventions.

Differentiating Psoriatic Arthritis from Osteoarthritis and Rheumatoid Arthritis: A Narrative Review and Guide for Advanced Practice Providers

Psoriatic arthritis (PsA) is a chronic inflammatory disease that affects multiple organ systems and is characterized by skin and joint manifestations. PsA is frequently undiagnosed and/or misdiagnosed, especially because of the similarities in clinical presentation shared with other arthritic diseases, including rheumatoid arthritis (RA) and osteoarthritis (OA). An accurate and timely diagnosis of PsA is crucial to prevent delays in optimal treatment, which can lead to irreversible joint damage and increased functional disability. Patients are usually seen by a number of different healthcare providers on their path to a diagnosis of PsA, including advanced practice providers (APPs). This review provides a comprehensive overview of the characteristic features that can be used to facilitate the differentiation of PsA from RA and OA. Detailed information on clinical manifestations, biomarkers, radiologic features, and therapeutic recommendations for PsA included here can be applied in routine clinical settings to provide APPs with the confidence and knowledge to recognize and refer patients more accurately to rheumatologists for management of patients with PsA.

Influence of Load and Transducer Bandwidth on the Repeatability of In Vivo Tendon Stiffness Evaluation Using Shear Wave Elastography

Objective:

To determine how different examination protocols with the use of transducers, of different bandwidths, and applied with varied tension to tendons would influence the sonographic study results.

Methods:

Thirty-one participants were divided into two groups, with one subject used for theoretical investigation (A) and the remaining participants (B = 30) forming the study cohort. Both sets of participants were examined with three different transducers (SL10–3, SL15–4, and SL18–7) as well as with variable loading on the Achilles tendon (relaxed, tensed, and loaded). The resulting coverage of the color map provided qualitative tendon stiffness and quantitative tendon stiffness values.

Results:

The estimated mean coverage extent, using elastographic color maps, produced by the three transducers was 98%, 98%, and 99%, respectively, in the relaxed state. Likewise, in the tensed state, mean coverage was 85%, 82%, and 77% in group A and 91%, 78%, and 71% in group B, respectively. Examining tendons that were loaded, the mean coverage was 68%, 42%, and 41%, respectively. The quantitative relaxed mean tendon elasticity values were 323, 366, and 393 kPa, respectively, in group A. Likewise, the relaxed mean values were 329, 341, and 358 kPa, respectively, in group B. The quantitative tensed mean tendon elasticity values were 413, 460, and 426 kPa, respectively, in group A. Likewise the tensed mean values were 412, 440, and 436 kPa, respectively, in group B.

Conclusions:

Varying the tendon loading significantly influenced the color map coverage, which governs the most reliable quantitative measurements on relaxed tendons. The best color map coverage was achieved using the transducer with the lowest frequency, regardless of the tension applied.

Peripheral spondyloarthritis: a neglected entity-state of the art

Peripheral spondyloarthritis (pSpA) refers to a number of seemingly different spondyloarthritis subsets in which psoriatic arthritis (PsA) is the most common, and symptoms of arthritis, enthesitis or dactylitis predominate the clinical presentation. Although formal classification criteria for pSpA have been introduced in 2011, only a minority of epidemiological and clinical studies addressed this clinical entity as a separate disease. Moreover, research on outcome measures and treatment modalities in pSpA has been mainly focused on PsA. Subsequently, all biological treatments are off-label in patients with non-psoriatic pSpA. Its neglected status has important implications for clinical practice since the emerging group of early-diagnosed non-psoriatic pSpA patients remains poorly characterised and lacks specific treatment recommendations. This review summarises what is currently known regarding pSpA in terms of epidemiology, clinical presentation, diagnosis and therapeutic approach.

Peripheral spondyloarthritis: Concept, diagnosis and treatment

Peripheral spondyloarthritis refers to spondyloarthritis with predominant peripheral (arthritis, enthesitis or dactylitis) involvement. Diagnosis can be challenging, particularly in the absence of SpA extra-articular manifestations such as uveitis, psoriasis or inflammatory bowel disease. Evaluation of disease activity should always include assessment of objective signs of inflammation, particularly in the presence of enthesitis as the sole peripheral manifestation, mainly due to the potential misdiagnosis with fibromyalgia tender points. Several recommendations for management/treatment of psoriatic arthritis have been published by EULAR and GRAPPA but none for peripheral SpA in general. NSAIDs and glucocorticoids are recommended as the first step of treatment in all peripheral manifestations, while conventional synthetic (cs) DMARDs seem only efficacious in arthritis. Several biologics and targeted synthetic (ts) DMARDs (TNFi, anti-IL17 and JAK-inhibitors) have been proven to be efficacious in peripheral involvement in PsA (arthritis and enthesitis), but studies on peripheral SpA are lacking.

Clinical and Ultrasound Assessment of Enthesis in Psoriatic Arthritis in a Romanian Cohort

INTRODUCTION

Spondyloarthritis (SpA) is a group of chronic inflammatory disorders which includes ankylosing spondylitis (SA), psoriatic arthritis (PsA), reactive arthritis (ReA), arthritis associated with inflammatory bowel disease (IBD) and undifferentiated spondyloarthritis (uSpA). The enthesis, the area of insertion of the tendon, ligament or joint capsule onto the bone, can be characterized as a central feature in PsA.

MATERIAL AND METHODS

The study included a number of 28 patients, 18 females and 10 males, with PsA hospitalized during 2016-2018 in the Department of Rheumatology of the Emergency County Hospital of Craiova. All the patients were diagnosed with psoriatic arthritis according to CASPAR criteria and had a history of entheseal pain, mandatory criteria for inclusion in the study. All patients underwent clinical examination, laboratory tests and musculoskeletal ultrasonography (MSUS).

RESULTS

The Belgrade Ultrasound Enthesitis Score (BUSES) was not significantly associated either with ESR (p=0.536) or CRP (p=0.965) values. Furthermore, the clinical evaluation through the LEEDS enthesitis index (LEI) showed no significant association with ESR (p=0.067) or CRP (p=0.206). Despite MSUS and clinical findings, there was no significant correlation between disease activity in psoriatic arthritis (DAPSA) and BUSES (p=0,549) or LEI (p=0,197). However, clinical and echographic scores (BUSES and LEI) were significantly associated (p=0.001).

CONCLUSIONS

Our study proved a significant correlation between LEI and BUSES, although in literature the evidence is contrasting. This is probably due to the fact that the majority of the patients had high disease activity which made the clinical assessment similar to the US. Further studies on more numerous groups of patients have to be conducted in order to debate the inconsistencies related to clinical and US examinations in patients with PsA.

Enthesitis and Dactylitis in Psoriatic Disease: A Guide for Dermatologists

Psoriatic arthritis (PsA) is an inflammatory arthritis that is estimated to affect approximately 30% of patients with psoriasis. Enthesitis and dactylitis, two hallmarks of PsA, are associated with radiographic peripheral/axial joint damage and severe disease. Clinical symptoms of enthesitis include tenderness, soreness, and pain at entheses on palpation, whereas dactylitis is recognized by swelling of an entire digit that is different from adjacent digits. Both ultrasound and magnetic resonance imaging can be used to diagnose enthesitis and dactylitis, especially in patients in whom symptoms may be difficult to discern. Delayed treatment of PsA can result in irreversible joint damage and reduced quality of life. Thus, it is recommended that dermatologists monitor patients with psoriasis for these two early and important manifestations of PsA.

Reliability of a consensus-based ultrasound definition and scoring for enthesitis in spondyloarthritis and psoriatic arthritis: an OMERACT US initiative

OBJECTIVES

To evaluate the reliability of consensus-based ultrasound (US) definitions of elementary components of enthesitis in spondyloarthritis (SpA) and psoriatic arthritis (PsA) and to evaluate which of them had the highest contribution to defining and scoring enthesitis.

METHODS

Eleven sonographers evaluated 40 entheses from five patients with SpA/PsA at four bilateral sites. Nine US elementary lesions were binary-scored: hypoechogenicity, thickened insertion, enthesophytes, calcifications, erosions, bone irregularities, bursitis and Doppler signal inside and around enthesis. Kappa statistics were used to evaluate reliability. Sonographers were also asked to state which lesions can be considered as inflammatory or structural and should be included in the final definition of enthesitis. Only the lesions, scored as present in at least 75% of the entheses considered as having an enthesitis, were included in the final definition.

RESULTS

The prevalence of detected lesions was quite low except for enthesophytes (55%) and bone irregularities (54%). Reliability ranged from poor to good (the lowest for thickened enthesis (kappa 0.1 (95% CI 0 to 0.7)) and the highest for enthesophytes (kappa 0.6 (95% CI 0.5 to 0.7)). When adjusted for low prevalence, kappa values increased for all lesions, with the best result observed for detecting Doppler signal at insertion (0.9) and for bursitis (0.8). The US components included in the final definition were hypoechogenicity, increased thickness at enthesis, erosions and calcifications/enthesophytes and Doppler signal at insertion.

CONCLUSION

By using a consensus-based stepwise approach, a final reliable US score and definition of enthesitis in SpA/PsA were produced. Further studies are sought for implementing this score in clinical trials and practice.

The Impact of Fibromyalgia in Spondyloarthritis: From Classification Criteria to Outcome Measures

The term spondyloarthritis (SpA) encompasses a broad clinical spectrum characterized by chronic inflammatory conditions affecting the sacroiliac joints, the spine but also peripheral joints and tendons and being additionally associated with the involvement of organs, such as bowel, eye and skin (1). Musculoskeletal pain is a key symptom in SpA. However, although low back pain and/or joint pain are characteristic for SpA, undifferentiated pain at different enthesial sites may also be a concomitant or even the first clinical presentation in some patients (2). In addition, fatigue is another important symptom often reported by patients with SpA, which substantially affects the quality of life (QoL) (3). Fibromyalgia (FM) is the most common diagnosis in patients complaining of chronic diffuse pain with fatigue and may occur alone or in association with chronic inflammatory diseases (4). The prevalence of FM ranges from 2 to 8% in the general population and it can reach up to over 50% in patients with other rheumatic and musculoskeletal diseases (RMDs) (5-7). FM has been identified as the most disabling RMD, based on the patients' perception that their medical condition is not properly recognized (8). This is also due to the poor knowledge about its pathogenesis, and therefore the lack of reliable biomarkers reveals a major unmet need requiring to be addressed in further research studies. Over the last decade, an increasing body of evidence described the impact of FM in SpA highlighting the pitfalls for correct classification, appropriate differential diagnosis and assessment of outcome measures in both conditions. The purpose of this review is to provide an overview of currently available data with regard to the coexistence and reciprocal features of FM and SpA.

Is ultrasonographic enthesitis evaluation helpful for diagnosis of non-radiographic axial spondyloarthritis?

The aim of this study is to evaluate the diagnostic utility of ultrasonographic enthesitis assessment in patients with non-radiographic axial spondyloarthritis (nr-axSpA) and to compare different sonographic scoring methods. Patients with nr-axSpA (n = 30) and mechanical back pain (MBP) (n = 30) were enrolled in the study with standardized clinical criteria. For both of the groups, a total of 18 entheses were evaluated in each patient with B mode ultrasound and power Doppler by a sonographer who is blinded to initial clinical and radiological assessments. Glasgow Ultrasound Enthesitis Scoring System (GUESS), Madrid Sonographic Enthesitis Index (MASEI) and D'Agostino grading system were performed. Intra-rater and inter-rater reliability analyses were evaluated with the intraclass correlation coefficient (ICC). There was at least one enthesitis in 96.7% of patients with nr-axSpA. Median values of the number of enthesitis were 5 in nr-axSpA and 0 in MBP. Mean GUESS total scores were 0.9 in MBP and 4.5 in nr-axSpA. Mean MASEI total scores were 2.3 and 10.5, respectively. The sensitivities were 96.7% and 93.3% for GUESS and MASEI while the detected specificities were 80% for both methods. For Intra-rater reliability analysis, ICC was calculated as 0.981 for GUESS and 0.975 for MASEI, while it was calculated as 0.964 and 0.962 for inter-rater reliability analysis. Thus, evaluation of enthesitis with ultrasound is a reliable, helpful tool for the distinction of patients with nr-axSpA from patients with MBP. We favored the use of MASEI because of assessing upper extremity, using power Doppler and having a correlation with disease activity.

The sonoanatomy of lumbar erector spinae and its iliac attachment - the potential substrate of the iliac crest pain syndrome, an ultrasound study in healthy subjects

Background

Iliac crest pain syndrome is a regional pain syndrome that has been identified in many patients with low back pain. Based on anatomical studies, it was suggested that the potential substrate of this syndrome might be the enthesis of the erector spinae muscle at the posterior medial iliac crest. As there have been no imaging studies of this important enthesis, our aim was to assess its characteristics by ultrasound.

Methods

Erector spinae enthesis was first studied in a cadaver. Then its characteristics were recorded in 25 healthy volunteers (median age: 28.92, SD: 5.31, mean Body Mass Index 22.61, SD: 3.38), with Esaote My Lab 7 machine using linear transducer (4–13 MHz).

Results

The cadaver study confirmed the attachment of a substantial part of erector spinae to a well-defined region on the medial posterior iliac crest. The US study in the volunteers consistently showed the entheses as typical hyperechoic fibrillar structures, slightly oblique to the skin in the longitudinal plane and attaching to the iliac crest. In the transverse plane, the entheses were seen as oval, densely dotted structures in contact with the superior edge of posterior superior iliac spine. Their mean thickness (4.9 ± 0.6 and 5.2 ± 0.7 mm longitudinally; 4.3 ± 0.6 and 4.4 ± 0.7 mm transversely), maximum width (16.3 ± 2.8 and 15.7 ± 2.3 mm) and depth (10.8 ± 7.3 and 10.6 ± 6.2 mm) on the left and right side, respectively, as well as their echostructure were recorded and described.

Conclusions

The erector spinae entheses could be assessed in detail by ultrasound, thus their pathological transformation associated with iliac crest pain syndrome could be identified.

Enthesitis: A hallmark of psoriatic arthritis

OBJECTIVE

To describe the growing importance of enthesitis in patients with psoriatic arthritis (PsA) and discuss the advantages and disadvantages of clinical and imaging methods currently used to assess enthesitis.

METHODS

PubMed literature searches were conducted using the terms psoriatic arthritis, entheses, enthesitis, pathology, imaging, ultrasound, magnetic resonance imaging, clinical, and indices. Articles were deemed relevant if they provided insight into the pathology, monitoring, and/or diagnosis of enthesitis in PsA, or if they discussed clinical or imaging indices used to assess enthesitis.

RESULTS

Enthesitis is an early manifestation of PsA that is associated with increased disease activity and reduced quality of life. A variety of clinical indices exist to assess enthesitis in PsA; however, the Leeds Enthesitis Index and Maastricht Ankylosing Spondylitis Enthesitis Score index have been the most frequently used indices in recent clinical trials. Limitations of these indices include an inability to discern structural involvement, risk of missing subclinical enthesitis, and lack of sensitivity in detecting enthesitis, especially in patients with central sensitization and/or pain amplification. Such limitations have led to the emergent importance of imaging techniques in the assessment of enthesitis. Although there have been recent advances in magnetic resonance imaging, ultrasound (US) appears to be the preferred method for detecting enthesitis because it allows for accurate assessment of the soft-tissue components of entheses and also for new bone formation. Hypoechogenicity, increased thickness of tendon insertion, calcifications, enthesophytes, erosions, and Doppler activity have been identified as important US characteristics of enthesitis.

CONCLUSION

Enthesitis is thought to be integrally involved in the pathogenesis of PsA and is associated with worse prognostic outcomes in patients with PsA. A validated US index with entheses that are less confounded by mechanical factors and obesity would be the most effective measure of enthesitis in PsA. As imaging techniques continue to advance, our understanding of enthesitis and its involvement in PsA will also improve.