Patient Positioning
Patient lies supine, knee 20°–30° flexed or extended. Place a small pillow under the joint to keep this position.
Probe Positioning
Place the transducer on a transverse plane in the midline over the quadriceps tendon. Perform the arthrocentesis in plane.


note: The intervention is best performed in plane from lateral, the needle is perfectly visible due to its parallel orientation to the probe.
note: in special circumstances a medial approach can be done.
note: in special circumstances the doppler mode can be used to visualize the medication and movement of the needle during injection better.