Ankylosis Definition

Also known as Anchylosis, this is a condition characterized by stiffness and pain of a specific joint. The condition mainly results from abnormal adhesion of the bones in the affected joint due to some disease or injury. Patients experience complete or partial rigidity which may result from inflammation of muscular or tendinous structures of the tissues of the involved joint or located outside it. It can occur in various parts of the human body including:

  • Ankle joint
  • Elbow joint
  • Temporomandibular joint (TMJ)
  • Knee joint
  • Finger joint
  • Shoulder joint

Ankylosis Causes

It can result from a wide range of factors, including the following:

Genetic Factors

Some researchers suggest certain gene mutations to be triggering factors. Studies show that any abnormality in the “ank” gene can amplify the function of the bone cells or osteoblasts which result in this disorder. The bone problem is also believed to have a tendency of running in families.

Fracture and Injury

Severe bone injury and trauma is another possible cause. Conditions like hemophilia, that can cause multiple episodes of bleeding, are also considered among the possible risk factors.

Rheumatoid Arthritis

Bone diseases like Osteoarthritis and Rheumatoid Arthritis are also suspected to result in Anchylosis. The continued connective joint tissue inflammation can destroy the synovial membrane, cartilage as well as the chondral bone structures. This reduces the mobility of the joint and leads to stiffness in the area.


Infection in specific joint can be a principal cause, depending on the extent of damage to the connective tissues like bone, cartilage, blood vessels, fluid and nerves within the joint. Damage to these tissues result in joint stiffness, while the decreased blood flow gradually leads to the death of the joint tissues. The degeneration of the bony tissues reduces the range of motion and causes the disorder.


Immobility or lack of exercise of a specific body part can eventually cause this bone abnormality. Individuals using wheelchairs and those on extended bed rest may develop this condition.

Ankylosis Symptoms

The disorder can give rise to symptoms like:

  • Joint pain
  • Fused joint bones
  • Swelling of the joints
  • Stiff joints
  • Joint immobility
  • Inflammation in the affected area

Individuals who have their TMJ affected by the disorder may suffer from the following additional symptoms:

  • Clicking in the jaw when opening and closing it
  • Difficulty in opening the jaw
  • Difficulty in moving the jaw to talk and eat

Ankylosis Prevention

It is not possible to prevent the condition when it is caused by genetic mutations. However, one can take the following preventive measures to prevent the Anchylosis caused by other factors:

  • Avoiding injury to the bony joints during activities like playing outdoor games.
  • Treating serious bone injuries immediately to prevent them from advancing into more serious disorders.
  • Treating diseases like Rheumatoid Arthritis properly and monitoring patients regularly for any signs of abnormal bone fusion.
  • Keeping all the joints flexible by regular exercise.

Ankylosis Diagnosis

Physicians perform a detailed physical examination of patients and studies the symptoms that are present. A number of diagnostic tests can be used for making and confirming the diagnosis. These involve:

Imaging Tests

Imaging exams like x-ray, CT (computed tomography) scan and MRI (magnetic resonance imaging) are very useful for detecting any abnormality in both the bony and soft joint tissues. These tests help to determine whether there are any calcium deposits in the bone joints.

Blood Tests

Certain blood tests, especially the one called sedimentation rate, are frequently used for this diagnosis. These tests help to determine the level of inflammation resulting from the condition. Diagnosticians place the blood sample in a test tube to measure the time taken by the red blood cells to settle at the bottom of the test tube. RBCs exposed to inflammation tend to cluster together and reach the bottom faster than normal.


This test is not directly useful for diagnosing the disorder. However, it helps diagnosticians to determine if a patient is suffering from any kidney disease which may be the reason behind symptoms like back pain. Some symptoms of certain kidney diseases may be mistaken for Ankylosis. Urinalysis helps to differentiate between the bone abnormality and kidney diseases.

Ankylosis Differential Diagnosis

It is important to rule out the following conditions with symptoms similar to Anchylosis during the diagnosis:

  • Ankylosing Spondylitis
  • Rheumatoid Spondylitis
  • Spondylitis
  • Spondyloarthropathy
  • Vertebral inflammation
  • Spondyloarthritis

Ankylosis Treatment

The disorder can be cured with proper management. Physical therapy and medication can help to reduce the joint stiffness and pain. Physiotherapists prepare a treatment plan depending on the location of the disorder and the severity of the symptoms. Exercises help to gradually increase the range of motion in the affected joint. The treatment for an Ankylosis-affected temporomandibular joint is slightly different from that of most other joints. Patients are prescribed certain jaw exercises to lessen the difficulty during opening and closing it.

Doing yoga regularly can be very helpful for reducing the symptoms of different forms of Anchylosis.


In case the above mentioned treatment options fail to cure the condition, surgical intervention may be necessary for treating it. Abnormal fusion of the bones and tissues can be separated by surgery. In extremely severe cases, the fused bony area may be removed surgically.

In patients with temporomandibular joint Anchylosis, the rounded side of their lower jaw (that constructs the temporal mandibular joint) may be surgically removed. Surgeons then replace the removed bone with prosthetic condyle.

The surgery is usually followed up with extensive physical therapy.

Ankylosis Prognosis

The outcome of the disorder is generally positive with proper treatment and management. In most cases, patients are allowed to return to their normal daily routines after the completion of treatment. However, leaving the condition untreated can result in serious problems as it can lead to a number of mild to severe complications including sprains and tendonitis.

Ankylosis and Spondylitis

Ankylosis is often confused with Spondylitis, although the two are different conditions. The former, as already mentioned, is marked by pain and rigidity of a particular joint. The latter, on the other hand, is characterized by more prominent swelling and aches in the affected joint. There is no proper cure for any form of Spondylitis and it is usually a life-long problem.

Spondylitis often involves Ankylosis as one of its characteristic features. In such cases, it is termed as Ankylosing Spondylitis – a severely weakening rheumatoid disease that affects 1 out of every 200 males and 1 out of every 500 females in the United States.

Ankylosis is a curable but potentially serious bone disorder that can affect people from various age groups. Early diagnosis along with prompt treatment allows its sufferers to reach complete recovery within a fairly short period of time.


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