How to perform arthrocentesis of the ankle

Siamak Moayedi, MD
19th Nov 2020

Anatomy of the ankle

The ankle joint is found between the tibia, fibula, and talus. To perform an arthrocentesis of the ankle, we will use the medial approach to access the ankle joint between the medial malleolus, the talus, and the tibialis anterior tendon (ankle dorsiflexor). 

Anatomy of the ankle: Top view of ankle with labels on the medial malleolus, tibialis anterior tendon, and talus. Illustration.

Figure 1.  Anatomy of an ankle. 


Ideal positioning for arthrocentesis of the ankle

For an ankle arthrocentesis, or ankle tap, you need to properly position your patient: 

  • Patient is laying down
  • Legs are straight
  • Affected foot flexed slightly forward 

foot flexed forward.  Alt text. Image of positioning of ankle for arthrocentesis. Image of ankle flexed forward. Cartoon.

Figure 2. Ideal positioning for arthrocentesis of the ankle. Patient is laying down with straight leg and the affected foot flexed forward. 

Once the patient is positioned, you will stand in front of the affected foot to perform the arthrocentesis procedure on the affected ankle joint. 


How to perform arthrocentesis of the ankle

The arthrocentesis procedure requires six simple steps to ensure a safe, clean, and painless ankle tap: 

  1. Direct a 20 gauge (G) needle to the inside of the tibialis anterior tendon and below the medial malleolus. 
  2. At a 45° angle, insert the needle 2–3 cm.
  3. Aspirate as soon as your needle enters the skin. 
  4. Stop advancing the needle when you see fluid. 
  5. Extract the joint fluid.
  6. Take the needle out and apply a bandage.

Superior view of ankle with bones and major tendons visible. Cartoon.

Figure 3. Needle positioning for an ankle arthrocentesis. Direct the needle at the inside of the tibialis anterior tendon, below the medial malleolus. At a 45­° angle, insert the needle 2–3 cm while aspirating until you see fluid. Extract the fluid, take the needle out, and apply a bandage. 

So there you have it, a summary for performing an ankle arthrocentesis. Great work!


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Recommended reading

  • Roberts, J. 2019. “Arthrocentesis”. In: Roberts and Hedges’ Clinical Procedures in Emergency Medicine and Acute Care. 7th edition. Philadelphia: Elsevier.