Sometimes, a shoulder arthrocentesis may be performed using radiological guidance because it may be required to confirm the presence of the fluid before aspirating. Radiological guidance can also be helpful in aspirating other deep and technically difficult joints such as the hip joint or spine.
A shoulder arthrocentesis is a relatively quick procedure but may be performed under local anesthesia to avoid pain. A needle of an appropriate size and length is introduced into the joints, and the synovial fluid is collected in syringes. The fluid is then sent for analysis under the microscope. Apart from the microscopic analysis, the appearance of the aspirated synovial fluid can indicate certain features. Normal fluid is clear or light yellow and is viscous. Inflammatory fluid appears darker yellow to cloudy in appearance and loses its viscosity. Purulent fluid (pus in the fluid) appears brownish to whitish and is opaque.
After the procedure, the patient would need to rest for a few minutes, soon after which they can resume normal activities. Patients may experience pain and bruising that resolves in a few days. Ice packs and painkillers can help reduce pain and bruising.
What is a shoulder arthrocentesis?
Joint aspiration (arthrocentesis) of the shoulder is a diagnostic procedure involving the extraction and analysis of the synovial fluid in the joints. It is an important component in diagnosing arthritis and differentiating an inflammatory arthritis from noninflammatory arthritis. An arthrocentesis can also be performed therapeutically (for pain relief, drainage of fluid, or injection of medications).
Any joint in the body can be aspirated. Joint aspiration is a relatively quick and inexpensive procedure to perform. It can be done in a clinic or hospital. It can be done by any physician, physician’s assistant or nurse who has the training and equipment.
When is a shoulder arthrocentesis done?
A shoulder arthrocentesis may be indicated for any patient with inflamed shoulder joints who does not have an established diagnosis. Inflamed joints are recognized by being red, warm, tender, swollen, and painful during movement. Some conditions that may require joint aspiration and analysis to establish diagnosis are as follows:
- Monoarticular arthritis (inflammation of the joints)
- Septic arthritis (infection of the joints)
- Joint effusion (swelling due to fluid accumulation in the body)
- Intra-articular fracture (fractures that involve the joint space)
- Crystal arthropathy (accumulation of calcium crystals in the joints and surrounding areas)
Joint aspiration may be performed as a treatment in certain conditions:
- Repeated aspirations can be part of the management of the septic joint to relieve discomfort and prevent joint damage.
- Aspiration can be considered in cases of hemarthrosis (blood in the joints) to prevent adhesions.
- Aspiration can be accompanied by injecting intra-articular medications such as corticosteroids or hyaluronic acid into the joints. Steroid injections reduce joint inflammation and pain and preserve joint structure and function. Hyaluronic acid lubricates the joints, decreases impact, delays joint aging, and reduces pain and stiffness.
When should a shoulder arthrocentesis not be done?
A shoulder arthrocentesis should be done with caution in patients with a bleeding disorder or those on anticoagulant drugs. Patients taking anticoagulant drugs may be advised to stop the medications few days before the procedure and resume after the procedure.
What are the complications of a shoulder arthrocentesis?
A shoulder arthrocentesis is a relatively safe procedure, and complications are rare. Common complications patients usually face are localized bleeding, pain and swelling and sometimes a reaction to local anesthesia. Infection of the joints may occur, which is called septic arthritis.
If other medications such as steroids are simultaneously injected, it may cause localized shrinkage or hypopigmentation of the skin. Long-term use of steroid injections may cause systemic side effects such as weight gain, poor bone health, puffy face, stretch marks, and easy bruising.