What techniques should be used when performing an arthrocentesis of the knee to rule out a septic joint?
The procedure should be performed using an aseptic technique. A topical antiseptic should be applied to the area. Nonsterile gloves should always be worn as part of universal precautions. Sterile gloves should be used if palpation of the area is foreseen subsequent to antiseptic preparation and before placement of the needle. A 25-gauge needle should be used to administer a local anesthetic (e.g., 1% lidocaine without epinephrine). The aspiration itself should be performed using an 18- or 21-gauge, 1.5-inch needle, when possible, and a 10-mL to 30-mL syringe. Aspiration techniques for other individual joints are described elsewhere. Ultrasonography can be a useful bedside tool for guiding needle placement for aspirations.