Ankylosis: Joint Stiffness and Fusion Causes, Types, and Treatment

Ankylosis = fibrous or bony fusion of a joint → loss of motion. Can be intra-articular (true) or extra-articular (false).

Causes

• Inflammatory: Ankylosing spondylitis (AS), psoriatic arthritis, reactive arthritis. Syndesmophytes bridge vertebrae.
• Infectious: Septic arthritis → fibrous/bony ankylosis.
• Traumatic: Intra-articular fracture, hemarthrosis, burns.
• Post-surgical: Arthrodesis (intentional fusion for pain/instability).
• Neuropathic (Charcot): Joint destruction → debris fusion.
• Genetic: Syndromes (e.g., fibrodysplasia ossificans progressiva).

Clinical Features

• Progressive stiffness, pain (early), then painless rigidity.
• Functional impairment (ADLs, gait, hygiene).
• AS: "bamboo spine," reduced chest expansion, uveitis, enthesitis.

Management

• Medical (inflammatory): NSAIDs, TNF inhibitors, IL-17/23 inhibitors, JAK inhibitors. Halts progression.
• Physical therapy: Maintain mobility, posture, chest expansion (AS).
• Surgical: Osteotomy (spinal realignment), joint replacement (hip/knee), arthrolysis (fibrous ankylosis).

Prevention

Early diagnosis/treatment of inflammatory arthritis. Mobilization after trauma/surgery.

Ankylosis is end-stage; intervention aims to prevent or delay fusion.