Postoperative analgesia for outpatient arthroscopic knee surgery with intraarticular clonidine

Intraarticular (i.a.) local anesthetics are often used for the management and prevention of pain after arthroscopic knee surgery. Clonidine prolongs the duration of local anesthetics. We designed this study to determine whether clonidine added to an i.a. injection would result in an analgesic benefit. Fifty patients were randomly assigned to one of five groups that received clonidine (either via the subcutaneous or i.a. route) or saline placebo with or without i.a. bupivacaine, as follows: Group 1 received 30 mL of 0.25% bupivacaine i.a.; Group 2 received 30 mL of 0.25% bupivacaine with clonidine (1 microg/kg) i.a.; Group 3 received 30 mL of 0.25% bupivacaine i.a. and subcutaneous clonidine (1 microg/kg); Group 4 received 30 mL of 0.25% bupivacaine with epinephrine (5 microg/mL) i.a.; and Group 5 received clonidine (1 microg/kg) in 30 mL of saline i.a.. The results of this study revealed a significant difference in analgesia from the i.a. administration of clonidine. The group who received a combination of i.a. bupivacaine and clonidine had a significantly decreased need for oral postoperative analgesics and an increased analgesic duration (P < 0.0001). We conclude that i.a. clonidine improved comfort in patients undergoing knee arthroscopy. Implications: The intraarticular administration of clonidine along with bupivacaine results in a significant improvement in analgesia compared with either drug alone. There was an increased time to first analgesic request and a decreased need for postoperative analgesics.