Dexamethasone and Dexmedetomidine as an Adjuvant to Intraarticular Bupivacaine for Postoperative Pain Relief in Knee Arthroscopic Surgery: A Randomized Trial.

BACKGROUND: Knee arthroscopy causes minimal trauma, however, good analgesia is required for early rehabilitation and return to normal life in the patients.

OBJECTIVE: We aimed to compare the analgesic effects of intraarticular dexamethasone and dexmedetomidine added to bupivacaine with those of bupivacaine alone.

STUDY DESIGN: This study uses a double-blind, randomized, controlled design with allocation concealment in a 3-armed parallel group format among patients undergoing arthroscopic meniscal surgery.

SETTING: The study was conducted at Assiut University Hospital in Asyut, Egypt. The study duration was from July 2016 to February 2017.

METHODS: After the ethics committee approval, 60 patients, with the American Society of Anesthesiologists (ASA) physical status of I or II, 20 - 50 years old, and scheduled for arthroscopic meniscal surgery were randomized in a double-blind manner to receive 18 mL intraarticular bupivacaine 0.25% with either dexamethasone 8 mg (group I), dexmedetomidine 1 ug/kg (group II), or 2 mL of normal saline (group III). The total volume of injectate used in each group was 20 mL. All of the patients received spinal anesthesia. Postoperatively, oral paracetamol 1000 mg was given every 8 hours, and oral tramadol 50 mg was administered, as needed, for rescue analgesia. The visual analog scale (VAS) pain scores, time to first analgesic request, and total dose of postoperative analgesics were recorded for 3 days postoperatively.

RESULTS: The VAS scores were lower in groups I and II compared with group III. The time to the first analgesic was significantly shorter in group III compared with groups I and II (P = 0.001). The total dose of rescue paracetamol was higher in group III compared with groups I and II (P = 0.001). No need for tramadol rescue analgesia was recorded in any of the groups. No significant differences between groups I and II were noticed.

LIMITATIONS: The limitations of this study include the lack of previous research to compare the effect of both intraarticular dexamethasone and dexmedetomidine added to bupivacaine for postoperative analgesia in arthroscopic knee surgery. Additionally, there was a short observation period for the detection of chondrotoxicity, if occurred.

CONCLUSION: The addition of dexamethasone or dexmedetomidine to a solution of bupivacaine 0.25% provided better analgesia than using bupivacaine alone.

CLINICAL TRIAL REGISTRATION: NCT02818985.

KEY WORDS: Intraarticular, knee arthroscopy, bupivacaine, dexmedetomidine, dexamethasone, postoperative pain.