What is done during a joint injection/aspiration?
We use local anesthesia when we are injecting fluid into joints or taking fluid out of the joint through aspiration. If we inject fluid, it is meant to medicate the joint in someway, whereas if we take fluid out of the joint, it is generally to collect fluid that can be tested by our laboratory as a way to help us determine the health of your joint.
What benefit is derived from a joint aspiration?
The fluid we acquire from the joint can be analyzed in a number of ways. For example, we can assess the number of white blood cells or red blood cells, which are indicators of immune health. We can evaluate the potential for gout or pseudogout with crystal analysis. We can also look directly for infection through culturing procedures.
At times, removing fluid from the joint is meant to be therapeutic, as removing excess fluid can reduce pain and increase mobility. Similarly, injections can sometimes also result in these outcomes.
What is usually injected into the joint space, and what is the benefit?
Injections for the joint can be used to address many conditions, which are typically inflammatory problems. These conditions include different forms of arthritis and gout. Anti-inflammatory injections of corticosteroids such as methylprednisolone or triamcinolone prevent the gathering of cells that leads to inflammation of the joint. Other agents, such as hyaluronic acid, can lubricate the joint, thereby providing pain relief and increased mobility.
Which joints are usually injected?
Joint injections can be used for a number of joints and are often used for the knee, ankle, elbow, shoulder, wrist, thumb, and other small joints in extremities. Lower back joints can also receive injections. Though the hip joint can be injected, it may require fluoroscopy for guidance.
What are the risks of joint injections and aspirations?
Most of the side effects associated with putting a syringe into joints are local. These effects include allergic reactions that irritate the skin. The joint may swell after injections and cause some pain. This reaction occurs in about 1 out of 50 patients. Other local reactions that occur much less frequently are whitening of the skin around the injection point, thinning of that skin, and tendon rupture.
In rare occasions, systemic side effects, such as fevers, organ reactions, and rashes may occur. Infection is a risk, but infections due to injections and aspirations are extremely rare. For instance, less than 1 in 15,000 corticosteroid injections results in infection.
These medications act locally and have few systemic side effects (such as a fever, rash, or a disturbance of an internal organ).