The aim of this observational study is to assess shoulder joint involvement in patients with axial spondyloarthritis using ultrasound and to compare the findings with those of healthy controls.

Axial spondyloarthritis (axial SpA) is a chronic inflammatory rheumatic disease that causes inflammation of the spine and sacroiliac joints. The condition usually begins at a young age (between 20 and 40 years). Common complaints include back pain, morning stiffness, and gradual restriction of spinal movement. Complaints of peripheral joint involvement may also be observed.

Shoulder involvement in patients with axial spondyloarthritis (axial SpA) represents a manifestation of the disease that can affect peripheral joints. Shoulder involvement typically develops as a result of an inflammatory process and is manifested by symptoms such as pain, swelling, and limitation of movement. The glenohumeral joint, acromioclavicular joint, subacromial bursa, and rotator cuff tendons are most commonly affected. Such peripheral joint involvement may indicate a more severe progression of axial SpA and an increased future disease burden.

Ultrasound is an inexpensive, non-invasive, and radiation-free imaging modality that is widely used in the assessment of the musculoskeletal system. In inflammatory rheumatic diseases such as axial SpA, ultrasound is a highly effective method for the early detection of inflammation. Inflammatory findings such as synovitis, tenosynovitis, enthesitis, and bursitis can be identified by ultrasound in the early stages of the disease. Early detection of these findings can slow disease progression and prevent joint damage by facilitating timely initiation of treatment.

The objective of this observational study is to evaluate the shoulder joint using ultrasound in patients with axial spondyloarthritis and to compare the findings with healthy controls.

The case group will consist of patients aged 18 to 65 who have been diagnosed with axial spondyloarthritis by a specialist in physical medicine and rehabilitation and who are being followed up at the PMR Outpatient Clinics of the Department of Physical Medicine and Rehabilitation, University of Health Sciences Gaziosmanpaşa Training and Research Hospital.

The control group will consist of individuals meeting the inclusion criteria, matched to the case group in terms of age and gender, and admitted to the PMR Outpatient Clinics of the Department of Physical Medicine and Rehabilitation, University of Health Sciences Gaziosmanpaşa Training and Research Hospital for any reason.

Physical examinations and ultrasound scans of the shoulder joint will be performed on all participants.

At the end of the study, data from both groups will be compared.

Inclusion Criteria:

• Patients with a radiographic or non-radiographic diagnosis of axial spondyloarthritis according to ASAS 2009 classification criteria
• Patients aged 18-65
• For healthy controls; people aged 18-65 years who attended PMR outpatient clinics for any reason, without a diagnosis of inflammatory disease and without complaints of shoulder pain.

Exclusion Criteria:

• People under 18 and over 65
• History of shoulder trauma
• History of upper extremity surgery
• History of fracture of the upper extremity
• History of malignancy
• Pregnancy

Axial SpA patients and healthy volunteers (have close demographic data with Axial SpA patients)