We will study 20 participants with active axial spondyloarthritis (axSpA) who are about to start biologic therapy as part of routine care. In brief, we will carry out the following assessments before and after therapy:~MRI of spine and Sacroiliac (SI) joints - modified Stoke Ankylosing Spondylitis Spine Score (mSASSS) scoring~Record standard Patient recorded outcomes (PROs): Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Global (BASG), Bath Ankylosing Spondylitis Metrology Index (BASMI), Bath Ankylosing Spondylitis Functional Index (BASFI), Ankylosing Spondylitis Disease Activity Score (ASDAS), Ankylosing Spondylitis Disease Activity Score Health Index (ASAS-HI), Euroquol 3 level health assessment (EQ5D-3L), work productivity and activity impairment questionnaire (WPAI), Short QUestionnaire to ASsess Health enhancing physical activity (SQUASH),~Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP)~IMU sensor tests in clinic for range of motion (ROM) in cervical, thoracic and lumbar spine.~IMU sensor tests at home for standardised function testing
This is an observational study using Inertial Measurement Unit (IMU) sensors to measure the effects of biological therapy on spinal mobility and function in axial spondyloarthritis. Participants will undergo MRI scans before and after therapy in parallel to the sensor tests to establish correlation between changes in inflammatory signs and changes in spinal mobility.