Ankylosing spondylitis (AS) is a chronic inflammatory rheumatic disease that mainly affects the spine and pelvis in its axial form. It is responsible for chronic inflammatory pain and sometimes ankylosis with significant functional retention.

Clinicians need markers capable of precisely measuring the restriction of range of motion in these patients, reflections of the activity and/or sequelae of the disease.

The Inverstigators validated movement markers in the AS by a device including inertial sensors (XSENS) and computer modeling. The accuracy and repeatability of the XSENS-Awinda system compared to the reference measurement system have been demonstrated. The XSENS-Awinda device offers new real-time evaluation possibilities for quantitative gait analysis. This opens the way to new diagnostic tools, prognostics and therapeutic perspectives for the clinician.

Ankylosing spondylitis (AS) is a chronic inflammatory rheumatic disease that mainly affects the spine and pelvis in its axial form. It is responsible for chronic inflammatory pain and sometimes ankylosis with significant functional retention. Today, these patients benefit from treatments by biotherapy but the functional monitoring of the therapeutic response is based on the clinical examination, questionnaires, and the measurement of CRP (C reactive Protein).

Clinicians need markers capable of precisely measuring the restriction of range of motion in these patients, reflections of the activity and/or sequelae of the disease. The prevention and/or the restoration of these movement limitations, responsible for gait/attitude/balance disorders, are also among the therapeutic objectives of AS.

In the AS, the synergy between the trunk and the lower limbs is altered with a restriction of the movements of the trunk in the three planes of space. The study of the kinematic variability seems to show a loss of complexity. In addition, MRI morphological examinations are insufficient to assess stiffness and functional disability related to AS.

The investigators validated movement markers in the AS by a device including inertial sensors (XSENS) and computer modeling. The accuracy and repeatability of the XSENS-Awinda system compared to the reference measurement system have been demonstrated. The XSENS-Awinda device offers new real-time evaluation possibilities for quantitative gait analysis. This opens the way to new diagnostic tools, prognostics and therapeutic perspectives for the clinician.

Inclusion Criteria:

• Age 18-65
• BMI between 18.5 and 30
• Written informed consent
• Same gender and age within +/- 3 years compared to an unmatched AS patient

Inclusion criteria specific to the AS group:

• Age 18-65

• BMI between 18.5 and 30

• Written informed consent

• AS meeting the ASAS (Assessment of Spondylo Arthritis International Society) criteria, i.e. with spinal pain ≥ 3 months old, with an age of diagnosis < 45 years, with:

  • Sacroiliitis on imaging AND ≥ 1 sign of spondylarthritis. OR
  • HLA-B27 (human leukocyte antigen-B27) positive AND ≥ 2 other signs of spondylarthritis

Exclusion Criteria:

• Traumatic, tumoral or infectious low back pain
• History of spinal fracture
• History of lumbar, pelvis, hips, ankles, and/or knees surgery
• Severe scoliosis defined by a Cobb angle > 50°
• Severe impairment of uncorrected visual acuity
• Concomitant pathology responsible for ataxia
• Lumbar arthrodesis of two or more stages
• Pregnant or breastfeeding women
• Patient unable to give consent: patient under guardianship or curators, mentally retarded, dementia, language barrier
• Patient not affiliated to a social security plan
• Patient under legal protection