Hydroxyapatite crystal disease facts

  • Hydroxyapatite is an essential mineral of normal bone.
  • Crystals of hydroxyapatite deposited in and about the joints cause inflammation.
  • Inflammation and pain are part of hydroxyapatite crystal disease.
  • This disease is distinct and different from gout and pseudogout.
  • Treatment includes measures to reduce inflammation and pain.

What is hydroxyapatite?

Hydroxyapatite is the major component, and an essential ingredient, of normal bone and teeth. It is hydroxyapatite that makes up bone mineral and the matrix of teeth.

What are hydroxyapatite crystals?

Hydroxyapatite molecules can group together (crystallize) to form microscopic clumps, called hydroxyapatite crystals.

Tiny crystals of hydroxyapatite sometimes form in or around joints and can cause inflammation of joints and tissues around the joints, such as tendons and ligaments. They have been described particularly as a cause of rotator cuff inflammation of the shoulder.

The inflammation caused by hydroxyapatite crystals has been referred to as hydroxyapatite crystal disease.

Hydroxyapatite Crystal Disease Symptoms & Signs

Signs and symptoms of hydroxyapatite crystal disease are related to localized inflammation caused by the crystals. Symptoms and signs can include

  • localized pain,
  • swelling,
  • joint tenderness, and
  • limited range of motion of the affected joint.

Is hydroxyapatite crystal disease the same as gout or pseudogout?

No. These conditions are similar in that they are all caused by the inflammation that results from the body's reaction to crystals. However, hydroxyapatite crystals are distinctly different from the crystals of pseudogout or gout. While hydroxyapatite crystals can sometimes also be found in the company of the calcium pyrophosphate crystals characteristic of pseudogout, these are quite different types of crystals.

How are hydroxyapatite crystals identified?

Sometimes, hydroxyapatite crystals can be seen clumped in the fluid of a joint that has developed arthritis. The crystals are usually so small as to be invisible under a regular microscope and thus require a special (electron) microscope for identification.

How is hydroxyapatite crystal disease treated?

The treatment of the inflammation caused by hydroxyapatite crystals includes rest, cold application, and medications to reduce inflammation. Cortisone-related medications injected into inflamed tissues can also sometimes help decrease inflammation and thereby relieve pain.


The term arthritis refers to stiffness in the joints. See Answer

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Medically reviewed by Aimee V. HachigianGould, MD; American Board of Orthopaedic Surgery


Garcia GM, McCord GC, Kumar R. "Hydroxyapatite crystal deposition disease." National Center for Biotechnology Information.