A synovial biopsy is the removal of a piece of tissue lining a joint for examination. The tissue is called the synovial membrane.

Biopsy - synovial membrane

The test is done in the operating room during an arthroscopy.

The health care provider will inject a numbing medicine (local anesthetic) into the area. An instrument called a trocar is inserted into the joint space. This tool helps push fluid in and out of the area. A biopsy grasper is inserted through the trocar and turned to cut out a tissue segment.

The tools are removed. A bandage is applied.

Tell your health care provider:

• If you are pregnant
• If you ever had a problem with anesthesia
• If you have any drug allergies
• If you have bleeding problems
• What medications you are taking (including any herbal medicines and supplements)

With the local anesthetic, you will feel a prick and a burning sensation. As the trocar is inserted, there will be some discomfort.

Synovial biopsy helps diagnose gout, bacterial infections, or other infections. It can be used to diagnose certain autoimmune disorders, like rheumatoid arthritis.

The synovial membrane structure is normal.

Synovial biopsy may identify the following conditions:

• Coccidioidomycosis (a fungal infection)
• Fungal arthritis
• Gout
• Hemochromatosis (abnormal accumulation of iron deposits)
• Tuberculosis
• Synovial cancer

The test may help diagnose rheumatoid arthritis, lupus, and other autoimmune diseases.

There is a very slight chance of infection and bleeding. Rarely, there is a chance of the needle striking a nerve or blood vessel.

 You will need to keep the wound clean and dry until your doctor or nurse says it is okay to get it wet.

El-Gabalawy HS. Synovial fluid analysis, synovial biopsy, and synovial pathology. In: Firestein GS, Budd RC, Harris ED Jr., et al, eds. Kelley's Textbook of Rheumatology. 8th ed. Philadelphia, Pa: Saunders Elsevier;2008:chap 48.