Information on Ankylosis


Ankylosis Overview

Ankylosis also known as anchylosis (from Greek means bent, crooked) is a abnormal fusion of a joint by bone or a tight fibrous union, often due to injury, trauma, surgery or disease, for example, septic arthritis (pyarthrosis), ankylosing spondylitis, healed tuberculosis of the bone etc. This will result in severe stiffening and immobility of a joint and even leads to complete loss of movement at the joint.

In dental ankylosis, it is a disorder where the tooth becomes fused to the bone, disrupting orthodontic movements and eruption. When ankylosis occur in the temporomandibular joint (TMJ, joint of the jaw), it is most likely to be caused by poor healing severe trauma or infection.

Tooth ankylosis poses several complications such as limiting the TMJ motion which causes inability to chew properly and in severe cases problems with speech. Other problems are submerged tooth due to the inability to erupt normally which potentially lead to a greater concern – arresting the growth of the permanent tooth. The development of the Ankylosispermanent tooth is affected when the root of an ankylosed tooth will not dissolve. In a growing child, ankylosis could also impact the growth of the lower jaw resulting in deformation of the facial skeleton.

Forms of ankylosis

Different forms of ankylosis:

  1. Artificial/ surgical ankylosis – The permanent fusion of two bones via surgical procedure. Also known as arthrodesis
  2.  bony ankylosis – fusion of the bones of a joint by the growth of bone cells which results in complete immobility
  3.  extracapsular ankylosis – the hardening a joint’s surrounding tissue causing stiffness in the joint
  4.  fibrous ankylosis – forming of fibrous tissue around bones of a joint which reduces joint mobility.
  5.  false ankylosis – refer to fibrous ankylosis
  6.  spurious ankylosis – refer to extracapsular ankylosis.
  7.  stapedial ankylosis – growth of spongy bones in the ear impacting movement of the stapes, causing hearing loss.
  8.  Tooth ankylosis – abnormal fusion of the root of a teeth to the bone
  9.  true ankylosis – refer to bony ankylosis.


The early and prominent symptoms of ankylosis is experiencing stiffness in the joint and decreased range of motion. In severe cases, it can cause pain and impair one’s ability to perform routine tasks.


Ankylosis can be diagnosed by performing clinical examinations like x-rays or imaging tests like MRI and CT scans to determine the abnormalities in the joints. In the particular case of ankylosing spondylitis, the individual’s medical record, family history and blood tests for (HLA-B27) also constitutes to the diagnosis.


Treatment varies depending on the area that is ankylosed. In most cases of ankylosis,a combination of physical therapy, exercise, medication and surgical procedure can greatly reduce the symptoms and relief the pain.

Posted by Lauren Burrows - July 25, 2013 at 3:57 pm