Pain after knee surgery is reported as severe for 60% of patients, and is a major concern in both hospitalised and ambulatory surgery patients. Pain control is particularly important, as adequate analgesia allows rapid mobilisation of the operated knee and prevents complications related to immobility. Several methods have been proposed to treat this pain, the most promising being injection of local anesthetic close to the femoral nerve. The injection of local anesthetics around the femoral nerve reduces sensation from the knee and provides better pain relief after surgery than narcotic medication. To prolong the duration of the analgesia, a small catheter must be positioned next to the nerve. Through this catheter, small quantities of local anesthetics can be continuously delivered for several hours after surgery, effectively relieving the worst of the pain.