The test can be done in the operating room or in your health care provider's office. There are multiple techniques used for synovial biopsy including surgery, arthroscopy or ultrasound guided needle biopsy.

During this procedure:

• Depending on the type of procedure, you may receivegeneral anesthesia,regional anesthesia or local anesthesia. With general anesthesia, you'll be pain free and asleep during the procedure. With regional anesthesia, you'll be awake, but the part of the body with the involved joint will be numb. With local anesthesia, only the joint is numbed and you will be awake during the procedure.

If you are having an arthroscopic procedure:

• Your 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.
• Your 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 will be sent to the lab for evaluation.

If you are having a needle biopsy:

• Your surgeon (radiologist, orthopedist or rheumatologist) will identify the site using ultrasound.
• The site of the biopsy will be cleaned and numbed.
• A needle sized trochar is inserted into the joint.
• A tool called a biopsy needle will be inserted through the trochar. Your surgeon will use the ultrasound to determine where to obtain the tissue from for biopsy. Your surgeon will cut a small piece of tissue with the biopsy needle. Multiple samples may be taken based on the clinical case. The biopsy needle will be removed from the joint and the tissue will be sent to the lab for examination.
• The trochar will be removed.
• A small bandage will be applied and stitches are not needed.
• Your surgeon will determine which method is best given your clinical case.

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

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.

Synovial biopsy helps diagnosegout and bacterial infections, or check for other infections. It can be used to diagnose autoimmune disorders such asrheumatoid arthritis, or uncommon infections like tuberculosis or fungal infections.

The synovial membrane structure is normal.

Synovial biopsy may identify the following conditions:

• Long-term (chronic) synovitis (inflammation of the synovial membrane)
• Coccidioidomycosis (a fungal infection)
• Fungal arthritis
• Gout
• Pseudogout
• 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

There is a very slight chance of infection and bleeding.

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

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

• Synovial biopsy

El-Gabalawy HS, Tanner S. Synovial fluid analyses, synovial biopsy, and synovial pathology.In: Firestein GS, Budd RC, Gabriel SE, Koretzky GA, McInnes IB, O'Dell JR, eds.Firestein and Kelley's Textbook of Rheumatology. 11th ed. Philadelphia, PA: Elsevier; 2021:chap 56.

Updated by: Neil J. Gonter, MD, Assistant Professor of Medicine, Columbia University, NY and private practice specializing in Rheumatology at Rheumatology Associates of North Jersey, Teaneck, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

• Autoimmune Diseases
• Biopsy
• Fungal Infections
• Gout
• Hemochromatosis
• Soft Tissue Sarcoma
• Tuberculosis