Knee arthroscopy with local anesthesia in ambulatory patients. Methods, results and patient compliance.

Knee arthroscopy in locally anesthetized ambulatory patients has been performed by filling the knee joint with 50 ml to 60 ml of 0.5% prilocaine, with adrenaline and with additional local infiltration at the sites of puncture. During the arthroscopic procedure the joint cavity is further distended with a mixture of the same local anesthetic diluted 1:10 with physiological saline or Ringer's acetate. During a normal arthroscopy of the knee joint about 500 mg of the local anesthetic is used. In 17 patients the blood concentrations of the local anesthetic used was measured 2.5 min to 135 min after instillation. The highest plasma levels found (after 60 min to 120 min) were still 10 to 15 times lower than an acceptable upper plasma level. These low blood levels probably depend on a slow absorption and that a considerable amount of the local anesthetic is washed out after the arthroscopy. A questionnaire was sent to 278 patients who during a two year period had undergone arthroscopy as an outpatient procedure. The degree of satisfaction for the anesthetic procedure was highest for general anesthesia where 97% were completely satisfied. Sixty-four percent were satisfied when given spinal anesthesia. However, 11% had to be put to sleep due to insufficient spinal block and 12% had headaches more than one day after outpatient spinal anesthesia. Seventy-seven percent were satisfied with local anesthesia. There was no statistical difference between the degree of satisfaction after local or spinal anesthesia.(ABSTRACT TRUNCATED AT 250 WORDS)