Every joint in the human body contains synovial fluid. This fluid, which is secreted into the joint cavity by the synovium or the synovial membrane, lubricates the joints and allows for ease of movement. The synovial membrane of joints is also the main place where inflammation occurs in joint diseases such as arthritis.
Synovial biopsies are performed when the physician cannot diagnose the issue based on routine measures, such as patient interviews, examinations, routine laboratory tests, and synovial fluid analyses. A physician might also order a biopsy when there is suspicion of a synovial infection. The synovial biopsy process is becoming more common in conducting arthritis and joint-related research.
Synovial biopsy is also referred to as a biopsy of the synovial membrane that lines the joint. This is because the process actually involves removing a piece of this membrane for examination.
Your physician will perform the biopsy when there is suspicion of an infection or gout. The biopsy can also be used to help diagnose other causes of joint inflammation such as autoimmune diseases. A synovial biopsy may also be helpful in cases where metabolic diseases such as hemachromatosis (deposition of iron) or cancer are suspected.
A synovial biopsy is an uncomfortable test, but with proper local anesthesia, the pain is tolerable. You will feel a prick and burning sensation when you receive the ocal anesthesia to numb the area and may feel some discomfort when the tissue is removed. Discomfort following the procedure will depend on whether a closed procedure is done in your doctor’s office or if a more involved procedure is performed using arthroscopy.
Following the procedure, ice should be applied to the joint to reduce pain and swelling. Physical activity should be limited to light activities such as walking which can begin several days after the procedure.
The synovial biopsy process may be performed at your physician’s office. This is called a closed-needle process. This process does not require any incisions and is a safe, effective way to collect tissue samples.
Your physician will inject local anesthesia into the site to limit pain and discomfort. Your doctor will then insert and instrument called a trocar into the joint. A trocar is an instrument that is slightly larger than a needle typically used for aspiration and it is used to clear the space of fluid. A tissue grabber is then threaded through the trocar to cut a sample of the synovial membrane.
As an alternative to the biopsy performed in your doctor’s office, you may have the procedure using arthroscopy, which is a surgery. Arthroscopy is most commonly used to diagnose and treat joint disorders (such as completing a knee surgery).
The main difference is that a tiny camera and light source are inserted into the joint via a small incision (cut). This allows the surgeon to see inside the joint. Another small incision allows the surgeon to insert tools to remove tissue, cartilage, fluid, or bone.
Arthroscopy is more complicated and expensive than a closed-needle procedure. However, it produces a larger tissue sample and the ability to see directly into the joint.
An abnormal test result could show:
- fungal infection
- abnormal accumulation of iron deposits in the joint
- synovial cancer
- autoimmune diseases
- rheumatoid arthritis
Synovial biopsy is regarded as a safe procedure. Although rare, the main risks include:
- allergic reaction to the medication or anesthesia
- difficulty breathing
- bleeding in the joint
- blood clot
- damage to the cartilage or ligaments of the joint
- infection in the joint
- injury to a blood vessel or nerve