Joint Ankylosis Causes and Characteristics

Inflammatory Arthropathies

Ankylosing spondylitis is the prototypical cause of spinal and sacroiliac joint ankylosis, characterized by progressive fusion that typically begins in the sacroiliac joints and ascends the spine 1, 2, 3.
The disease is strongly associated with HLA-B27 and leads to ossification of spinal ligaments and facet joint fusion, creating the classic "bamboo spine" appearance 4.
Peripheral joint ankylosis can occur in spondyloarthropathies, though less commonly than axial involvement 5, 6.
The American College of Radiology recommends considering ankylosing spondylitis in patients with spinal and sacroiliac joint ankylosis 1, 2, 3.
The Annals of the Rheumatic Diseases reports that ankylosis in spondyloarthropathies is associated with HLA-B27 and leads to ossification of spinal ligaments and facet joint fusion 5.

Adult-Onset Still's Disease (AOSD) can cause pericapitate ankylosis, developing in 25% of AOSD patients with the characteristic pattern of intercarpal and carpometacarpal joint space narrowing 8.
AOSD also causes ankylosis of distal interphalangeal joints, intertarsal joints, and cervical zygapophyseal joints 8.
The chronic articular form of AOSD carries particularly high risk for progressive ankylosis, according to the Annals of the Rheumatic Diseases 7, 8.

Erosive hand osteoarthritis targets interphalangeal joints and can progress to marked bone attrition, instability, and bony ankylosis 9, 10.
This subset shows subchondral erosion that may advance to complete fusion, typically with more severe pain and functional impairment than non-erosive osteoarthritis 9.
Ankylosis in erosive OA is specific to this subtype and distinguishes it from nodal osteoarthritis, as reported by the Annals of the Rheumatic Diseases 9, 10.

Plain radiographs remain the gold standard for detecting established ankylosis, showing complete joint space obliteration and bony bridging 9.
In ankylosing spondylitis, patients with spinal ankylosis have high risk of unstable fractures from minor trauma, requiring high clinical suspicion and CT imaging when symptomatic 1, 2, 3.