Ankylosing spondylitis (AS) is a chronic inflammatory condition that primarily affects the spine and the joints where the spine meets the pelvis, known as the sacroiliac joints. It belongs to a broader group of inflammatory conditions called spondyloarthritis. Ankylosing spondylitis causes pain, stiffness and progressive loss of spinal mobility, particularly in the lower back.
The term ankylosing means stiff or fused, while spondylo refers to the vertebrae of the spine. In some people, ongoing inflammation leads to new bone formation, which can cause sections of the spine to gradually fuse together. This reduces flexibility and may contribute to a forward-stooped posture. Importantly, not everyone with ankylosing spondylitis develops spinal fusion, especially with early diagnosis and modern management.
Ankylosing spondylitis typically begins in early adulthood, often before the age of 40. Symptoms usually develop gradually rather than following a specific injury. Because early symptoms can mimic common mechanical back pain, diagnosis is often delayed.
Today, ankylosing spondylitis is increasingly described within the spectrum of axial spondyloarthritis (axSpA). This includes both non-radiographic axSpA (where changes are seen on MRI but not X-ray) and radiographic axSpA (traditionally called ankylosing spondylitis). This distinction is important because it allows earlier diagnosis and treatment.
Physiotherapy for ankylosing spondylitis is a cornerstone of management at all stages of the condition. Alongside medical treatment, physiotherapy helps maintain spinal mobility, preserve posture, manage pain and stiffness, improve chest expansion, and support long-term function and independence.
Key Facts
- Arthritis Australia reports that ankylosing spondylitis most commonly begins in late adolescence or early adulthood, usually before 40 years of age. 🔗
- Up to 90% of people with ankylosing spondylitis carry the HLA-B27 gene, although most people with the gene do not develop the condition. 🔗
- International clinical guidelines support exercise and physiotherapy as essential components of ankylosing spondylitis management to reduce pain and improve function. 🔗
Risk Factors
- Presence of the HLA-B27 gene.
- Family history of ankylosing spondylitis or related spondyloarthritis conditions.
- Onset of chronic back pain before 40 years of age.
- Male sex, although females are commonly affected and may present differently.
Symptoms
- Chronic low back pain that develops gradually rather than after a single injury.
- Back stiffness, particularly in the morning or after periods of rest.
- Pain in the buttocks, often alternating from side to side.
- Hip pain or stiffness, which may affect walking and daily activities.
- Reduced spinal mobility, making bending, twisting or turning the head more difficult.
- Fatigue that is disproportionate to activity levels.
- Chest tightness or difficulty taking a deep breath due to rib joint involvement.
Aggravating Factors
- Prolonged sitting or inactivity, which typically worsens stiffness.
- Periods of active inflammation (flare-ups).
- Poor sleep quality, which can amplify pain and fatigue.
- Reduced overall physical activity or deconditioning.
Causes
The exact cause of ankylosing spondylitis is not fully understood. It is believed to result from an interaction between genetic factors and environmental triggers. The strongest genetic association is with the HLA-B27 gene, which plays a role in immune system regulation.
Having the HLA-B27 gene does not mean a person will definitely develop ankylosing spondylitis, and people without the gene can still develop the condition. Environmental factors such as infections or immune system changes are thought to trigger inflammation in genetically susceptible individuals.
Ankylosing spondylitis is not caused by posture, occupation or physical activity. However, these factors can influence symptom severity, stiffness and functional limitations once the condition is present.
How Is It Diagnosed?
Ankylosing spondylitis is diagnosed using a combination of clinical history, physical examination, imaging and blood tests. There is no single test that confirms the diagnosis.
Clinicians look for features of inflammatory back pain, including symptoms lasting longer than three months, morning stiffness lasting more than 45 minutes, improvement with exercise, and worsening with rest.
Physiotherapists play an important role in recognising features suggestive of inflammatory back pain and recommending medical review when ankylosing spondylitis is suspected.
Investigations & Imaging
- MRI of the sacroiliac joints and spine
- Detects early inflammatory changes before structural damage is visible on X-ray, allowing earlier diagnosis.
- X-ray imaging
- Identifies later-stage structural changes such as joint erosion or spinal fusion.
- Blood tests (HLA-B27, CRP, ESR)
- Support diagnosis and assess inflammation, though normal results do not exclude ankylosing spondylitis.
Grading / Classification
- Non-radiographic axial spondyloarthritis
- Inflammatory back pain with MRI changes but no visible changes on X-ray.
- Radiographic ankylosing spondylitis
- Structural changes visible on X-ray, including sacroiliac joint damage or spinal fusion.
- Disease activity phases
- Symptoms typically fluctuate between flare-ups and periods of lower disease activity or remission.
Physiotherapy Management
Physiotherapy management for ankylosing spondylitis is essential across all stages of the condition. Exercise and education are considered core treatments and are strongly supported by evidence. Physiotherapy aims to maintain spinal mobility, preserve posture, reduce pain and stiffness, improve breathing capacity, manage fatigue, and support long-term independence.
Physiotherapy programs are individualised and adjusted over time depending on disease activity, flare-ups, fitness level and personal goals.
Exercise
Exercise is one of the most effective interventions for ankylosing spondylitis. Programs typically include spinal mobility exercises, stretching, strengthening and aerobic conditioning.
Spinal extension, rotation and side-bending exercises help counter stiffness and reduce the tendency toward flexed posture. Strengthening focuses on postural muscles, trunk stability and hip strength to support efficient movement.
Aerobic exercise such as walking, swimming or cycling improves cardiovascular health, reduces fatigue and supports overall wellbeing. Physiotherapists tailor exercise intensity and volume based on disease activity and tolerance.
During flare-ups, exercise is modified rather than stopped, focusing on gentle mobility and circulation to prevent excessive stiffness.
Activity Modification
Activity modification helps manage symptoms while maintaining participation in daily life. Physiotherapists provide strategies to break up prolonged sitting, introduce regular movement, and adjust work or study environments.
Pacing strategies and rest breaks are particularly important during periods of increased inflammation or fatigue.
Manual Therapy
Manual therapy may be used to address joint stiffness, muscle tension and pain. Techniques are applied cautiously and are always combined with active exercise to maintain long-term benefits.
Postural Retraining
Postural retraining aims to preserve an upright spinal posture and prevent progressive stooping. Physiotherapists use postural education, strengthening and ergonomic advice to support spinal alignment during daily activities.
Education
Education is central to ankylosing spondylitis rehabilitation. Physiotherapists educate people about the inflammatory nature of the condition, flare-up management, pain strategies, fatigue management and the importance of long-term exercise adherence.
Other
Other physiotherapy strategies include chest expansion and breathing exercises to maintain rib mobility, cervical spine mobility for neck involvement, and guidance on assistive devices or supports when required.
Other Treatments
Medical management may include non-steroidal anti-inflammatory drugs, corticosteroids, disease-modifying anti-rheumatic drugs and biological medications. These treatments aim to reduce inflammation and slow disease progression. Physiotherapy works alongside medical treatment to optimise function and quality of life.
Surgery
Surgery is uncommon in ankylosing spondylitis but may be considered in advanced cases with severe joint damage or spinal deformity. Procedures such as hip replacement or corrective spinal surgery may be recommended. Physiotherapy is essential before and after surgery to optimise outcomes.
Prognosis & Return to Activity
Ankylosing spondylitis is a lifelong condition with a variable course. Many people experience periods of increased symptoms followed by remission. With early diagnosis, modern medical treatment and consistent physiotherapy, many individuals maintain good mobility, posture and participation in work, sport and daily life.
Physiotherapy supports long-term activity engagement rather than avoidance, helping people remain active safely as symptoms fluctuate.
Complications
- Progressive spinal stiffness and reduced mobility.
- Spinal fusion in advanced disease.
- Postural changes such as increased thoracic kyphosis.
- Reduced chest expansion affecting breathing.
Preventing Recurrence
- Maintain regular physiotherapy-guided exercise to preserve mobility and posture.
- Avoid prolonged inactivity; frequent movement reduces stiffness.
- Address flare-ups early with appropriate medical and physiotherapy input.
- Monitor posture and chest mobility over time.
When to See a Physio
- Persistent back pain and stiffness lasting more than three months, especially if worse in the morning.
- Reduced spinal mobility or posture changes.
- Difficulty managing flare-ups or fatigue.
- For long-term exercise planning and progression.