Ankylosing spondylitis (AS) -- now classified as axial spondyloarthritis (axSpA) -- is a chronic inflammatory arthritis primarily affecting the spine and sacroiliac joints. Over time, inflammation causes new bone formation (syndesmophytes) that progressively bridges vertebrae, leading to reduced spinal mobility, characteristic postural changes, and a distinctive altered gait.
How AS Changes Posture and Gait
Advanced AS produces a characteristic stooped posture:
- Loss of lumbar lordosis (flattening of the lower back curve)
- Thoracic kyphosis (increased forward rounding of the upper back)
- Forward head posture as a compensation
- Hip and knee flexion contractures (hips and knees cannot fully straighten)
- Reduced cervical rotation -- limited ability to look left or right
This postural profile alters gait mechanics: the centre of mass shifts forward, increasing fall risk. The altered visual axis (looking downward due to forward head posture) further impairs spatial awareness during walking.
Walking Cane in Early vs. Advanced AS
In early AS, pain is the primary symptom and mobility is relatively preserved. A walking cane is not routinely needed early, except during flares when sacroiliac or hip joint involvement causes pain-limited weight-bearing.
In moderate to advanced AS:
- Balance is compromised by forward-shifted centre of mass
- Hip involvement causes pain and reduced hip extension
- Falls are increasingly likely due to postural instability
- A walking cane provides balance and confidence on uneven terrain and in low-light conditions
Cane Handle and AS Posture
The stooped posture of advanced AS means the standard cane height formula (handle at wrist crease) may not apply. If the patient stands with permanent hip and knee flexion, the effective arm height is lower than in a standing person. Cane height should be measured in the patient actual standing posture, not in a corrected posture they cannot achieve.
AS Stage and Walking Aid
| AS Stage | Dominant Problem | Walking Aid Indication |
|---|---|---|
| Early (inflammatory; limited fusion) | Pain on movement and at rest; morning stiffness | Cane during flares; none required in remission |
| Moderate (partial fusion; posture change) | Forward posture; reduced range; hip involvement | Cane for outdoor, terrain, and fatigue |
| Advanced (bamboo spine; severe kyphosis) | Severe postural instability; fall risk; hip contracture | Cane essential outdoors; consider rollator for severe kyphosis |
Related: Walking Cane for Lumbar Spinal Stenosis. Explore DaiWalk walking canes.
