Hydroxyapatite crystal deposition disease

Definition

Basic calcium phosphates are often detected in synovial fluid of patients with osteoarthritis and inflammatory arthritis. In some cases, the crystals themselves, usually hydroxyapatite, appear to be inflammatory. Common scenarios in which hydroxyapatite crystal deposition contribute to arthritis include Milwaukee shoulder, Philadelphia finger, syringomyelia, osteoarthritis flares, and neuropathic arthritis. These crystals are not detectable by polarized microscopy, and generally require electron microscopy or staining with alizarin red for identification.

Therapy

Pharmacological

Treatment is directed at relieving symptoms and may include non-steroidal anti-inflammatories, arthrocentesis, or intra-articular steroids. If possible, efforts to reverse the underlying cause (i. e. neuropathy) should be addressed.

Non-pharmacological

For osteoarthritic joints, supportive measures such as bracing, physiotherapy, and joint replacement surgery may be helpful.

Prognosis

Most joints...