Effects of tourniquet time in knee arthroscopy patients receiving intraarticular morphine combined with bupivacaine.

The purpose of the study was to compare the duration of analgesia and the amount of supplemental postoperative analgesics required when morphine combined with bupivacaine was injected into the knee joint at the end of knee arthroscopy surgery. Varying tourniquet times of 0, 8, or 16 minutes were used after the injection. The variables examined were the duration of analgesia, and the amount of supplemental postoperative analgesics required in each subgroup. A sample of 45 subjects was recruited and studied from an outpatient surgery center. The 45 subjects were randomly assigned to one of three groups (n = 15). At the end of the procedure, morphine combined with bupivacaine was injected into the intraarticular space and the tourniquet was released or left on for an additional 8 or 16 minutes. The duration of analgesia and the amount of supplemental postoperative analgesics administered in a 24-hour period were measured. No statistical differences were found between groups. All patients received analgesia with no reported side effects. Increasing the tourniquet time had no effect on the duration of analgesia or the amount of supplemental narcotics required in the postoperative period.