Objectives: Digital annular pulleys (DAPs) are important anatomical structures for finger function. The anatomy, histology and imaging assessment of DAPs, particularly at the level of their entheses, are still not clearly defined. The advent of high-frequency US transducers opened new perspectives in evaluating submillimetre-scale structures, such as pulleys, paving the way for their global assessment. The study aimed to characterize DAPs from an anatomical, histological and US perspective, focusing on the detection and complete description of pulley entheses. Methods: US assessment and gross anatomy dissection were conducted on 20 cadaveric hands to study DAP thickness and structure, including enthesis identification. The results of the US and anatomical measurements were correlated. DAP entheses identified by US were characterized via histological analysis. DAPs in 20 healthy controls (HCs) were detected and measured by US. The A1, A2 and A4 DAP entheses were assessed using a new dynamic manoeuvre to better evaluate those structures. Results: A total of 1200 DAPs (400 cadaveric, 800 HCs) were analysed. The cadaveric study demonstrated strong correlation between anatomical and US measurement of DAPs (r = 0.96). At the histological level, DAP entheses at the volar plate, sesamoid bones or phalangeal ridges contained fibrous and fibrocartilaginous tissue. US assessment of A1, A2 and A4 DAPs in HCs allowed the identification of 718/720 (99.73%) entheses. Conclusion: US is an effective tool to detect and study DAPs. DAP entheses reveal both fibrous and fibrocartilaginous characteristics. A newly described manoeuvre to optimize DAP enthesis visualization enhances their detection by US.

Background/Objectives: The objective of this study is to investigate the intra- and inter-explorer reliability of different lung ultrasound (LUS) scores in patients with suspected rheumatoid arthritis with associated interstitial lung disease (RA-ILD). Methods: Fourteen consecutive patients with suspected RA-ILD based on the presence of respiratory symptoms, lung function tests (LFTs) or imaging alterations were recruited. The screening protocol consisted of an LFT, a chest X-ray, and HRCT. LUS examinations of different B-line and pleural line scores including 14 intercostal spaces were performed by three experienced sonographers, guaranteeing blinding. Intra- and inter-explorer reliability were calculated for all LUS scores and at the intercostal space level by weighted Cohen’s kappa and Fleiss’ kappa, respectively, relying on absolute differences using Stata/IC 14.2 software^® (StataCorp, College Station, TX, USA). Results: Both global (ĸ = 0.73–0.82) and binary (ĸ = 0.80–0.90) scores of B lines showed substantial to excellent intra-explorer reliability, with slightly better results for the binary score. The inter-explorer reliability was equally excellent for the global score (ĸ = 0.93) and the binary score (ĸ = 0.90) of B lines. The intra-explorer reliability of the semiquantitative pleural score was excellent for all the sonographers (ĸ = 0.88–0.91), and the binary pleural score had slightly lower intra-explorer reliability (ĸ = 0.77–0.84). Regarding inter-explorer reliability, both semiquantitative and binary pleural scores were equally excellent (ĸ = 0.84). Good to excellent inter-explorer reliability was found in all the scanned areas. Conclusions: Substantial to excellent intra- and inter-explorer reliability of different feasible B-line and pleural LUS scores were found, adding evidence in favor of the potential implementation of LUS for RA-ILD diagnosis in clinical practice.

Objective: To develop and validate a minimally invasive ultrasound (US)-guided biopsy technique to collect entheseal tissue from the common extensor tendon (CET) enthesis at the lateral humeral epicondyle. Methods: Seven sonographers performed a US examination of the CET on six human cadaveric upper limbs to locate the enthesis using an anatomical landmark-based approach. An adapted mini-arthroscopic system was introduced under US guidance to the target site for sample collection. At the end of the procedure, a dye was injected through the guide needle, followed by dissection, to confirm the sampling location. Histology and immunohistochemistry analyses were performed to assess the quality and representativeness of the samples. The reliability of the procedure among operators was evaluated by analysing the rate of successful sampling. Results: 24 samples were collected. The target site to be biopsied was identified as the insertion of the extensor carpi radialis brevis component of the CET. On dissection, the stain used to verify sampling accuracy was confirmed within the defined target area, with no damage to adjacent structures. Histology and immunohistochemistry indicated that most of the samples exhibited characteristics consistent with entheseal tissue (21 out of 24). All participants identified the CET and successfully completed the procedure, demonstrating reliable sample quality across operators. Conclusion: We developed a landmark-based approach to perform a minimally invasive full controlled US-guided biopsy of the CET enthesis that showed to be feasible and reproducible. We believe that this standardised, minimally invasive technique will widespread a reliable collection of entheseal tissue for future clinical and translational studies.

To evaluate the prevalence of clinical and ultrasound (grey-scale and Doppler) abnormalities in joints, periarticular structures and nails of children affected by skin psoriasis (PsO). Cross-sectional study including consecutive children affected by PsO. A systematic clinical and ultrasound evaluation of joints, entheses, tendons and nails were performed by independent examiners blinded to each other assessment. 57 Children: 26 girls (46%), mean age of 9 ± 4 years, divided into two groups, asymptomatic (Asy, 42 children) and symptomatic (Sy, 15 children) according to musculoskeletal pain. Differences were observed between the two groups in relation to age (9 ± 3 in Asy vs 11 ± 4 yrs in Sy, p< 0.05), PsO duration (2.4 ± 2.4 vs 5.4 ± 3.9 yrs, p< 0.001), systemic treatment (23 [54.8%] vs 2 [13.3%], p< 0.01), tender joint count (0 vs 12 children [80%], p< 0.001), swollen joint count (0 vs 3 [20%], p< 0.01) and entheseal pain (0 vs 10 [66.7%], p< 0.001). Ultrasound evaluation showed statistically significant differences between Asy and Sy groups for the presence of ultrasound abnormalities (16/42 [38%] vs 12/15 [80%]), synovitis (1/42 [2%] vs 4/15 [25%]) and enthesitis (4/42 [9.5%] vs 5/15 [33%]). Three children in the Sy group were classified with juvenile psoriatic arthritis (JPsA). Ultrasound abnormalities were higher in the Sy group with synovitis and enthesitis as the most prevalent findings. Asy patients were more frequently under systemic treatment. Ultrasound and a systematic clinical evaluation are useful tools for detecting subclinical JPsA in children with PsO and musculoskeletal symptoms.