Background Tendon complaints are common in both healthy adults and patients with psoriatic arthritis (PsA). Ultrasound (US) could be used to investigate whether these are located at the enthesis and of inflammatory origin, as it is able to detect structural changes and inflammatory changes using Power Doppler.
Objectives We aim to describe the difference in ultrasound abnormalities in the entheses of patients with recently diagnosed PsA, patients with established PsA and young healthy volunteers (20–30 years). using the MASEI US score
Methods Consecutively newly diagnosed PsA patients participating in the Dutch south west Psoriatic Arthritis Registry (DEPAR), patients with >2 years PsA and healthy volunteers (aged 20–30 years) were asked to participate. An ultrasound was performed by one examiner unaware of clinical findings using an Esoate Mylab 60 (probe LA-435 and LA-523). The triceps, quadriceps, proximal and distal patellar and Achilles tendon insertion, plantar fascia (i.e. the locations of the Madrid Sonographic Enthesis Index; MASEI) and the tendon insertion at the lateral epicondyle of the elbow were investigated (1). In each location structural changes, erosions, calcifications, increased thickness and Power Doppler signal and is some locations bursitis were evaluated, resulting in a total score (range 0–158).
Results In total, 25 newly diagnosed PsA patients (A), 25 established PsA patients (B) and 25 healthy volunteers (C) participated. The median of the MASEI+ score was for A 18 (IQR 15–30), for B 22 (IQR 15–27) and for C 10 (IQR 5–15) (Table 1).
Of note, the reference values for thickness of the Quadriceps tendon at the superior pole (6.1 mm), the inferior pole (4.0 mm) and the insertion at the tuberosity of the tibia (4.0 mm) were exceeded by 50%, 58% and 70% of the entheses of healthy volunteers (50 tendons). Also the degree of Power Doppler signal varied from one spot of signal to a confluent signal in large section of the enthesis, suggesting different levels of inflammation or possibly even false-positive findings. The images were re-evaluated for PD signal (assigning 1 point for one spot of signal, 1.5 for 2 or 3 spots, 2 for confluent small area or 3 points for confluent large area). When excluding increased thickness of knee entheses and using the re-evaluated PD scores the median MASEI was resp. 13 (IQR 10–22.5), 13.5 (IQR 9.5–18) and 3 (IQR 1.5–8) (Table 1).
Conclusions US structural changes and inflammation in the entheses are common in both early and established PsA patients using the MASEI. In healthy young adults US enthesitis was only observed around the knee. MASEI ultrasound score differentiated PsA patients from healthy volunteers when dropping the knee tendon enthesis thickness and applying a refined Power Doppler score. Our findings need to be confirmed in a larger cohort of healthy controls and patients.
de Miguel E, Cobo T, Munoz-Fernandez S, Naredo E, Uson J, Acebes JC, et al. Validity of enthesis ultrasound assessment in spondyloarthropathy. Ann Rheum Dis. 2009;68(2):169–74.
Disclosure of Interest None declared