ENTHESITIS-DRIVEN PAIN IN PSORIATIC ARTHRITIS: ULTRASOUND EVIDENCE FOR EARLY ENTHESOPATHY

E. Russu¹, L. Chislari², L. Groppa² | ¹Nicolae Testemitanu State Medical and Pharmaceutical University, Timofei Mosneaga Republican Clinical Hospital, Chisinau, Republic of Moldova; ²Nicolae Testemitanu State Medical and Pharmaceutical University, Chisinau, Republica of Moldova

Background and Aims. Pain in psoriatic arthritis (PsA) is frequently related to inflammation at the enthesis. Early identification of enthesopathy may improve diagnostic accuracy and treatment monitoring. This study evaluated ultrasound features of enthesopathy and inflammatory joint changes associated with pain in PsA.
Methods. A cross-sectional study included 70 PsA patients and 30 rheumatoid arthritis (RA) controls. Clinical evaluation assessed inflammatory activity and joint pain. Musculoskeletal ultrasound examined 3,232 joints for synovitis, enthesopathy, tenosynovitis, cartilage changes, and bone erosions. Doppler ultrasound evaluated synovial vascularization, while MRI was used as a reference method in 15 patients (56 joints).
Results. Ultrasound detected intra-articular effusion in 293/3,232 joints (9.1%) and synovial proliferation in 296 joints (9.16%), predominantly with low echogenicity (67.6%). Enthesopathy of the patellar ligament and quadriceps tendon was observed in a significant proportion of PsA patients and occurred more frequently than in RA (p=0.007). Tenosynovitis was detected in 30 anatomical sites, most commonly affecting finger flexor tendons. MRI confirmed joint effusion in 92.9% of examined joints, supporting ultrasound findings. Doppler vascularization correlated with clinical inflammatory activity (r=0.50) and laboratory markers (ESR and leukocytosis). Ultrasound sensitivity reached 100% for detecting effusion, cartilage changes, osteophytes, and tenosynovitis, while sensitivity for enthesopathy was 85.7% with 100% specificity.
Conclusions. Enthesopathy represents an important structural correlate of pain in PsA. Musculoskeletal ultrasound allows early detection of entheseal inflammation and provides a reliable tool for diagnosis, differential assessment from RA, and monitoring of treatment response.