Ankylosis

When the structures outside the joint are affected, the term "false ankylosis" has been used in contradistinction to "true ankylosis", in which the disease is within the joint. When inflammation has caused the joint-ends of the bones to be fused together, the ankylosis is termed osseous or complete and is an instance of synostosis. Excision of a completely ankylotic shoulder or elbow may restore free mobility and usefulness to the limb. "Ankylosis" is also used as an anatomical term, bones being said to ankylose (or anchylose) when, from being originally distinct, they coalesce, or become so joined that no motion can take place between them.

Causes

• Ankylosing spondylitis is a type of arthritis in which there is long-term inflammation of the joints of the spine.
• Other forms of arthritis may sometimes also lead to ankylosis, including rheumatoid arthritis and reactive arthritis
• Osteoarthritis usually confers osteophyte formation, which may eventually fuse across joints. Osteoarthritis is believed to be caused by mechanical stress on the joint and low-grade inflammatory processes.
• Arthrodesis is the intentional creation of ankylosis in a joint.
• Noma—a gangrenous disease still widespread among malnourished children living on the borders of the Sahara desert—can cause ankylosis of the maxilla and mandible, impairing the ability to speak and eat.
• Fibrodysplasia ossificans progressiva is a rare bone disease in which muscle, tendons and ligaments turn to bone. This leads to progressive ankylosis of almost all joints.