Arthrocentesis is a procedure where a needle attached to a syringe is inserted through the skin, and into a joint space (capsule) to remove fluid (synovial fluid). The carpus (wrist), elbow and stifle (knee) are the most common joints to obtain fluid from in dogs and cats.
Normally, the joint space contains a very small amount of synovial fluid for lubrication.
Certain diseases, such as tick-transmitted diseases (e.g. Lyme disease), immune-mediated diseases and cancers can cause excess fluid (joint effusion) to accumulate within the joints.
These diseases cause lameness and joint pain. Any fluid obtained by performing arthrocentesis is submitted to a veterinary pathologist for analysis for infection, inflammation and cancer. Pain relievers, sedation and occasionally general anesthesia is required for patient’s comfort when performing an arthrocentesis.
You pet may benefit from an arthrocentesis if your veterinarian has diagnosed lameness or joint pain not related to arthritis, or if there is suspected joint effusion.