The lateral approach is preferred since the synovial cavity distends laterally in 75 percent of patients. Landmarks include the lateral patella, superior patellar pole, and the iliotibial band. A 1.5 inch (4 cm) 22-gauge needle is inserted at an angle of approximately 70 degrees, halfway between the undersurface of the patella and the middle of the iliotibial band. One mL of local anesthetic is placed in the lateral retinaculum and intraarticularly. The needle is advanced to a depth of 1.5 to 3 inches (4 to 8 cm) and joint fluid is aspirated.
