Joint Aspiration (Arthrocentesis)

Joint aspiration is typically performed by a doctor or ancillary health care provider as an office procedure or at the bedside of hospitalized patients.

Arthrocentesis, commonly known as joint aspiration, is a medical procedure used to diagnose and treat joint disorders. The term “arthrocentesis” comes from the Greek words “arthro” (joint) and “kentesis” (puncture), literally meaning “puncturing of a joint.” This procedure involves using a needle to remove excess fluid, known as effusion, from within a joint capsule.

The term “aspiration” generally means to draw out fluid or tissue, often using suction or a syringe. In the case of arthrocentesis, aspiration specifically refers to the removal of fluid from a joint space. This fluid can then be analyzed to help diagnose conditions such as arthritis, gout, or infections such as septic arthritis.

Arthrocentesis or joint aspiration is typically performed on joints such as the knee, ankle, elbow, or hip. It is particularly useful when there is a need to determine the cause of joint swelling or pain. Arthrocentesis can be a valuable tool both for diagnosis and therapeutic relief in various musculoskeletal conditions.

Joint aspiration is typically performed by a doctor or ancillary health care provider as an office procedure or at the bedside of hospitalized patients.

Patients do not need any special preparation before a joint aspiration. The aspiration is easily performed in a doctor's office as an outpatient procedure. Pain is minimized by topical or local anesthetics applied onto the patient's skin or just beneath the skin. Usually, there is a momentary, slight amount of pain as the needle is inserted into the patient's joint space. Withdrawal of the fluid into the syringe does not typically cause pain. Injection of medication into the joint does not typically cause pain. There is very slight pain sometimes as the needle is withdrawn from the joint. Any pain is reduced by topical or local anesthetics that block pain sensation.

Joint aspiration, also called arthrocentesis, is performed when there is suspicion of infection to relieve pain and swelling caused by excess fluid in the joint, to obtain a fluid sample for analysis, or to administer medications directly into the joint. It serves both diagnostic and therapeutic purposes in various clinical scenarios.

Diagnostic purposes:

• Evaluation of joint disorders: Arthrocentesis helps diagnose various joint disorders by analyzing the joint fluid (synovial fluid). Conditions such as septic arthritis, gout, pseudogout, and rheumatoid arthritis can be identified based on the characteristics of the aspirated fluid.
• Detection of infections: It is crucial for detecting bacterial, fungal, or viral infections within the joint. A culture and sensitivity test of the joint fluid can guide appropriate antimicrobial therapy.
• Assessment of inflammatory conditions: Measuring the levels of white blood cells, crystals, protein, and glucose in the joint fluid helps in assessing inflammatory and noninflammatory joint conditions.

Therapeutic purposes:

• Relief of symptoms: Removing excess joint fluid can alleviate pain, swelling, and pressure within the joint, providing significant symptom relief.
• Administration of medications: Medications such as corticosteroids or hyaluronic acid can be directly injected into the joint space to reduce inflammation or lubricate the joint.

Arthrocentesis is also used in specific medical procedures, conditions, and clinical settings:

• Knee drain: In cases of severe knee joint effusion, where there is an excessive accumulation of joint fluid, a knee drain might be used to continually remove fluid over a certain period.
• Knee joint effusion: Knee joint effusions are frequent and can arise from various causes such as trauma, degenerative changes, infection, or inflammation. This condition, characterized by the accumulation of excess fluid in the knee joint, can cause pain, swelling, and limited movement. Arthrocentesis can help determine the underlying cause, relieve symptoms, drain infected fluid, or administer medication.
• Suspected septic arthritis: When a joint infection is suspected, immediate aspiration is crucial to prevent joint damage.
• Gout and pseudogout: For patients presenting with acute joint pain and swelling, joint aspiration can help identify the presence of urate or calcium pyrophosphate crystals, confirming the diagnosis.
• Rheumatoid arthritis and other autoimmune disorders: Aspiration can assist in diagnosing and monitoring inflammatory joint diseases by analyzing the joint fluid.
• Traumatic injury: In cases of joint trauma, aspiration can be evaluated for hemarthrosis (bleeding into the joint) or fat globules, indicating a possible fracture.

Large joint arthrocentesis

Large joint arthrocentesis refers to the aspiration of fluid from major joints such as the knee, hip, shoulder, or elbow. This procedure is particularly important in:

• Management of major joint effusions: Large collections of fluid within a joint can cause significant discomfort and functional impairment. Aspiration can provide immediate relief.
• Evaluation of systemic conditions: In patients with systemic inflammatory or infectious conditions, large joint arthrocentesis can help determine the extent of joint involvement.
• Postsurgical complications: Following joint surgery, aspiration can be used to evaluate and manage complications such as infection or persistent effusion.

Joint aspiration is a valuable tool in the diagnosis and management of various joint disorders. It helps in relieving symptoms, guiding treatment, and providing essential diagnostic information, particularly in cases involving knee joint effusion and large joint arthrocentesis.

Arthrocentesis is commonly used to diagnose various conditions including:

• Septic arthritis: This is a joint infection, usually caused by bacteria. It leads to inflammation, pain, and swelling in the affected joint. Arthrocentesis can help diagnose septic arthritis by analyzing the aspirated fluid for the presence of bacteria and an elevated white blood cell count.
• Crystal arthropathies (gout and pseudogout): Gout is caused by the buildup of uric acid crystals in the joints, while pseudogout is caused by calcium pyrophosphate dihydrate (CPPD) crystals. Arthrocentesis can help diagnose these conditions by identifying the presence of monosodium urate crystals (in gout) or CPPD crystals (in pseudogout) under a microscope.
• Rheumatoid arthritis: Rheumatoid arthritis is an autoimmune disease that causes joint inflammation. While it cannot be definitively diagnosed through arthrocentesis alone, analysis of the joint fluid can help support the diagnosis by showing an elevated white blood cell count and other inflammatory markers.
• Osteoarthritis: Osteoarthritis is a degenerative joint disease. Arthrocentesis can help diagnose osteoarthritis by ruling out other conditions and showing a normal or slightly elevated white blood cell count in the synovial fluid.
• Hemarthrosis: It refers to bleeding into the joint space, often due to trauma. Arthrocentesis can help diagnose hemarthrosis by identifying the presence of red blood cells in the synovial fluid.
• Inflammatory arthritis: In addition to rheumatoid arthritis, other inflammatory arthritis such as psoriatic arthritis and ankylosing spondylitis can be supported by arthrocentesis findings of an elevated white blood cell count in the synovial (joint) fluid.
• Lupus arthritis: Lupus arthritis is associated with systemic lupus erythematosus (SLE). The aspirated synovial fluid analysis can show inflammatory changes. Arthrocentesis helps differentiate lupus arthritis from septic arthritis or other inflammatory arthritis conditions.
• Reactive arthritis: Reactive arthritis occurs as a reaction to an infection elsewhere in the body. Aspirated fluid analysis typically shows an inflammatory profile but is sterile, indicating the absence of active infection in the joint itself.
• Synovial chondromatosis: A rare condition where benign cartilaginous nodules form in the synovium of the joint. Aspirated fluid analysis may show loose bodies or fragments of cartilage.
• Pigmented villonodular synovitis (PVNS): A rare, benign proliferative disorder of the synovium. Arthrocentesis may show blood-stained synovial fluid and hemosiderin-laden macrophages.
• Lyme disease: An infectious disease caused by the Borrelia burgdorferi bacterium, transmitted by ticks. Synovial fluid analysis can show inflammatory changes, while polymerase chain reaction (PCR) testing may detect the presence of Borrelia DNA.

It’s important to note that while arthrocentesis can diagnose these conditions, further tests and examinations are often required to confirm the diagnosis and plan appropriate treatment.

A joint injection is a procedure whereby a medicine is injected into the joint space with a needle and syringe. Occasionally, cortisone (an anti-inflammatory medication) or hyaluronic acid derivatives (a synthetic joint lubricant, approved for pain relief of the knee in degenerative arthritis) are injected into the joint during the joint aspiration. A cortisone injection can rapidly relieve joint inflammation and further reduce symptoms. Simultaneous joint aspiration followed by joint injection can often be done by changing the aspiration syringe with the syringe for the injection (such as for steroid injection). In this way, the joint injection does not need to be done as a separate procedure.

A joint aspiration procedure (arthrocentesis) may be performed to obtain joint fluid to test in the laboratory.

The skin over the joint is cleaned by the health care professional using a liquid, typically an iodine solution (Betadine). A local anesthetic is used in the area of the joint; either by injection, a topical liquid coolant, or both. A needle with a syringe attached is inserted within the joint (joint injection), and joint fluid is drawn back under suction (aspirated) into the syringe. For certain diseases and medical conditions, the health care professional will also inject medicine into the joint after fluid removal. The needle is then removed and a Band-Aid or dressing is applied over the entry point.

Joint aspirations can be performed under medical guidelines by qualified doctors, including general physicians, internists, orthopedic surgeons, rheumatologists, interventional radiologists, emergency room physicians, as well as nurse practitioners and physician assistants.

There are few health contraindications to a joint aspiration. People who are taking blood-thinning medicines (anticoagulants such as warfarin [Coumadin]) for underlying health reasons can have bleeding into the joint. The risk of this is extremely low, unless the level of blood thinner is too high (making the blood very thin), in which case the procedure may need to be temporarily delayed. The risk of bleeding into the joint is minimized when the physician uses the thinnest needle possible and applies cold packs after the procedure. If the skin over a joint is infected, the joint should not be aspirated, in order to prevent the infection from spreading into the joint.

Medical complications of joint aspiration are uncommon. Possible complications of the aspiration procedure include a reaction to the local anesthetic, local bruising, or minor bleeding into the joint. If cortisone is used, there may be loss of pigment in the skin (a light-colored spot may develop). A rare but serious complication of the procedure is infection of the joint (septic arthritis).

With corticosteroid injections, additional uncommon complications include inflammation in the joint as a result of the medication crystallizing, shrinkage (atrophy) or loss of pigment of skin at the injection site, increased blood sugar (worsening of diabetes mellitus), and aggravation of preexisting infection elsewhere in the body. If multiple injections with corticosteroids are given too frequently, it is possible to develop systemic side effects (side effects throughout the body), such as weight gain, puffy face and trunk, and easy bruising. Injection of hyaluronic acid derivatives may cause local inflammation and swelling of the joint due to a reaction to the medication. Hyaluronic acid injections into the knee joint for pain relief are generally given no more frequently than every six months.

Arthrocentesis is generally considered safe; however, there are potential risks and complications associated with the procedure.

Risks and complications of arthrocentesis

• Infection: One of the primary risks of arthrocentesis is infection. Although the procedure is performed under sterile conditions, introducing a needle into the joint can potentially lead to an infection, known as septic arthritis. Signs of infection include increased pain, swelling, redness, warmth around the joint, and fever.
• Bleeding: Bleeding can occur at the puncture site, especially in patients with bleeding disorders or those taking anticoagulant medications. Hemarthrosis, or bleeding into the joint, is a rare but possible complication.
• Pain and discomfort: Patients may experience pain and discomfort during and after the procedure. The insertion of the needle can cause temporary pain, and some soreness at the site may persist for a few days after the procedure.
• Joint damage: Although rare, there is a potential for joint damage due to the needle. This can include damage to the cartilage or other joint structures, which may result in increased joint pain or other complications.
• Allergic reactions: Patients may have allergic reactions to the antiseptic used to clean the skin, the local anesthetic, or other materials used during the procedure.
• Needle breakage: Although extremely rare, there is a possibility that the needle could break during the procedure, which would require surgical intervention to remove the broken piece.
• Synovial fluid leak: After the procedure, there may be a small amount of synovial fluid leakage from the puncture site. This typically resolves on its own with minimal intervention.

Common side effects of arthrocentesis

While the serious complications mentioned above are relatively rare, some common side effects can occur, such as:

• Temporary pain: Mild to moderate pain at the site of the needle insertion is common. This pain usually subsides within a few hours to a couple of days.
• Swelling: Some patients may experience minor swelling around the joint following the procedure.
• Bruising: Bruising at the puncture site is possible and generally resolves without intervention.
• Localized warmth: The area around the joint may feel warm temporarily after the procedure.

Most common side effects can be managed with simple measures such as rest, ice application, and over-the-counter pain relievers such as acetaminophen or ibuprofen. Patients are advised to avoid strenuous activities involving the affected joint for a short period to allow for proper healing. Patients should seek medical attention if they experience severe pain, significant swelling, persistent redness, warmth around the joint, or fever, as these could be signs of infection or other complications.

The level of pain experienced during arthrocentesis can vary based on several factors, including the patient's pain threshold, the specific joint involved, the underlying condition causing the joint effusion, and the skill of the health care provider performing the procedure.

How painful is arthrocentesis?

Most patients experience only temporary, manageable pain that resolves within a day or two after the procedure.

• Discomfort during the procedure: Most patients report feeling some discomfort or pressure when the needle is inserted into the joint. The sensation can range from mild to moderate pain. The use of a local anesthetic can help minimize pain at the injection site.
• Pain from joint swelling or infection: If the joint is swollen or infected, the procedure might be more uncomfortable due to the sensitivity of the inflamed tissues.
• Post-procedure soreness: After the procedure, some patients may experience soreness at the site of needle insertion, which usually resolves within a few hours to a couple of days.
• Pain management: To manage pain, health care providers may apply a cold pack to the joint after the procedure and recommend over-the-counter pain relievers if necessary.

Arthrocentesis can cause some discomfort or mild pain, but health care providers take steps to minimize this. If you experience severe or persistent pain, should be reported to the provider.

There is no recovery time required after joint aspiration. Doctors typically suggest avoiding stressful activity with the joint for at least 24 hours, especially if medication (such as steroid injection) has been injected by joint injection. If pain increases after the procedure while at home, the doctor should be notified.

• What is the recovery time after arthrocentesis? The recovery time after arthrocentesis is typically short, with most patients able to resume activities immediately or after resting the affected joint for 4 to 24 hours. Local anesthetics usually wear off in 2 to 4 hours, and mild soreness may persist for a day or two.
• Can arthrocentesis be used to treat joint pain? Yes, arthrocentesis can be used to treat joint pain by removing excess fluid from the joint, which can relieve pressure, reduce pain, and improve joint mobility.
• How long does an arthrocentesis procedure take? An arthrocentesis procedure typically takes about 10 to 15 minutes.