Synovial biopsy

Definition

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

Alternative Names

Biopsy - synovial membrane; Rheumatoid arthritis - synovial biopsy; Gout - synovial biopsy; Joint infection - synovial biopsy; Synovitis - synovial biopsy

How the Test is Performed

The test is done in the operating room, often during an arthroscopy. This is a procedure that uses a tiny camera and surgical tools to examine or repair the tissues inside or around a joint. The camera is called an arthroscope. During this procedure:

• You may receive general anesthesia. This means you'll be pain free and asleep during the procedure. Or, you may receive regional anesthesia. You'll be awake but the part of the body with the joint will be numb. In some cases, local anesthesia is given, which numbs only the joint.
• The surgeon makes a tiny cut in the skin near the joint.
• An instrument called a trocar is inserted through the cut into the joint.
• A tiny camera with a light is used to look inside the joint.
• A tool called a biopsy grasper is then inserted through the trocar. The grasper is used to cut a small piece of tissue.
• The surgeon removes the grasper along with the tissue. The trocar and any other instruments are removed. The skin cut is closed and a bandage is applied.
• The sample is sent to a lab for examination.

How to Prepare for the Test

Follow your health care provider's instructions on how to prepare. This may include not eating and drinking anything for several hours before the procedure.

How the Test will Feel

With the local anesthetic, you will feel a prick and a burning sensation. As the trocar is inserted, there will be some discomfort. If the surgery is performed under regional or general anesthesia, you will not feel the procedure.

Why the Test is Performed

Synovial biopsy helps diagnose gout and bacterial infections, or rule out other infections. It can be used to diagnose autoimmune disorders such as rheumatoid arthritis, or uncommon infections like tuberculosis or fungal infections.

Normal Results

The synovial membrane structure is normal.

What Abnormal Results Mean

Synovial biopsy may identify the following conditions:

• Long-term (chronic) synovitis (inflammation of the synovial membrane)
• Coccidioidomycosis (a fungal infection)
• Fungal arthritis
• Gout
• Hemochromatosis (abnormal buildup of iron deposits)
• Systemic lupus erythematosus (autoimmune disease that affects the skin, joints, and other organs)
• Sarcoidosis
• Tuberculosis
• Synovial cancer (very rare type of soft tissue cancer)
• Rheumatoid arthritis

Risks

There is a very slight chance of infection and bleeding.

Considerations

Follow instructions for keeping the wound clean and dry until your provider says it is OK to get it wet.

References

El-Gabalawy HS. Synovial fluid analyses, synovial biopsy, and synovial pathology. In: Firestein GS, Budd RC, Gabriel SE, McInnes IB, O'Dell JR, eds. Kelley and Firestein's Textbook of Rheumatology. 10th ed. Philadelphia, PA: Elsevier; 2017:chap 53.

West SG. Synovial biopsies. In: West SG, ed. Rheumatology Secrets. 3rd ed. Philadelphia, PA: Elsevier Mosby; 2015:chap 9.