Arthrocentesis: Indications and Procedure

Introduction:

In the human body, a joint is where two bones meet. Joints are essential for the human body as they provide structural support and enable movement and flexibility. Based on their structure and function, joints are classified into three types, which are as follows:

• Synovial Joints - Synovial joints are formed by the connection of bones in the presence of synovial fluid. Synovial fluid helps lubricate and cushion the joint during movement. Synovial joints are responsible for most movements in the human body. The joints found in the shoulders, hips, and knees are some examples of synovial joints.

• Cartilaginous Joints - Cartilaginous joints are formed by the connection of bones to the cartilage. The cartilage acts as a shock absorber. Cartilaginous joints are partially movable joints. An instance of a cartilaginous joint exists between the vertebrae in the spine.

• Fibrous Joints- Fibrous joints are formed by connecting bones with fibrous tissue. It is an immovable joint. Fibrous joints are found between the skull bones.

With age or due to an underlying disease condition, the synovial fluid may reduce, or the cartilage may deteriorate, leading to painful joints due to inflammation.

What Is the Importance of Synovial Joints?

The most common injuries that can affect the synovial joint are as follows:

Inflammation of the Synovial Joint:

• Inflammation of the synovial joint can happen for multiple reasons, such as age, injury, or infection.

• Synovial joint inflammation is termed arthritis. The most common type is osteoarthritis, which occurs when the joint's cartilage wears down from regular use or if the joint has been injured before. When the cartilage of the joint gets thinner, the bones in the joint feel more pressure, and the joint starts to produce synovial fluid as a protective mechanism, which causes swelling and pain.

• Nerves in the joint can also get over-activated and send pain signals.

Depositions Within the Joint:

• When excess uric acid is present in the human body due to excess production or failure of proper excretion, the uric acid gets accumulates within the joints in the form of crystals of uric acid.

• The condition is termed gout and causes excruciating pain and swelling in the affected joints.

• The toe and knuckle joint (metatarsophalangeal joint) is the most commonly affected joint.

Synovial Membrane Inflammation

• The synovial membrane is a layer of tissue that encapsulates the synovial joint and produces the synovial fluid. Overuse or bacterial infection of the synovial joints can cause synovial membrane inflammation, called synovitis.

• Individuals with synovitis may experience excruciating pain with or without the presence of an inflamed joint. The pain is experienced mainly due to the multiple nerve endings present in the joint.

• The synovial fluid can be aspirated to diagnose the condition causing joint pain or as a therapy to relieve joint pain.

What Is Arthrocentesis?

Arthrocentesis is a procedure where the synovial fluid is aspirated from the synovial joints for diagnostic or therapeutic purposes. For diagnostic purposes, the fluid removed from the joint can be analyzed to help diagnose the underlying cause of inflammation, infection, or the presence of crystals. Removing the excess fluid can reduce pressure within the joint space and relieve the pain for therapeutic purposes. An arthrocentesis procedure can benefit conditions where excessive joint swelling causes limited mobility.

What Are the Indications for Arthrocentesis?

Arthrocentesis is indicated for the following reasons:

• Presence of an infection inside a joint.

• To diagnose the reason for joint inflammation, such as gout.

• Giving medicine directly into a joint (viscosupplementation) for fast relief of pain and swelling, especially in conditions like rheumatoid arthritis.

• Removing blood from a joint after an injury.

How Is Arthrocentesis Done?

The health of the individual and the joint to be aspirated determine if the procedure can be done under local anesthesia inside a doctor's clinic or if admission to a hospital is required to do the method under general anesthesia. Arthrocentesis is a simple procedure; hence, it is most often done under local anesthesia in a clinic. The steps for arthrocentesis are as follows:

• Once the individual is comfortably positioned, the right spot to insert the needle is found by checking for bony landmarks around the joint or using ultrasound for better guidance.

• Clean and sterilize the joint and the area around it with an antiseptic solution and cover it with a sterile drape.

• To alleviate pain and numb the targeted area, it is recommended to administer a local anesthetic using a needle of 25 or 27 gauge.

• Insert a larger needle connected to a syringe into the joint space.

• Drain the fluid or blood from the joint using the syringe.

• For larger effusions, a three-way stopcock may be used.

• Collect the fluid in appropriate tubes for laboratory analysis.

• In cases of therapeutic purposes, after aspiration, the fluid syringe is replaced with a medication syringe, and medicine is injected into the joint space.

• Apply a dressing or bandage to the puncture site and apply pressure to stop the bleeding.

Post-Op Care:

• Resting for 48 hours.

• Avoiding weight lifting.

• Having medications, if necessary, to ease discomfort or pain at the aspiration site.

• Immediately reporting to the hospital in case of any severe discomfort.

What Are the Risks of Arthrocentesis?

Arthrocentesis is a relatively safe procedure. However, in rare cases, the possible risks are as follows:

• Improper sterilization or the presence of a skin infection can cause infection of the joint space.

• Bleeding within the joint cavity may occur in individuals with bleeding disorders or an accidental knick of a blood vessel during the procedure.

• Individuals allergic to anesthetic ingredients may show an allergic reaction.

What Are the Contraindications for Arthrocentesis?

Arthrocentesis can be done for any individual, but it must be done with caution if the individual has:

• Skin infection or cellulitis at the aspiration site.

• Bleeding disorders.

• A prosthesis at the aspiration site.

• An acute fracture at the aspiration site.

• An uncooperative nature.

Conclusion:

The health of joints is essential for the smooth movement of the body, and joint pain can significantly impact one's daily activities. Arthrocentesis is a safe procedure that can help diagnose and treat joint-related conditions by analyzing synovial fluid and offering appropriate treatment options.