Intra-articular versus intravenous administration of dexmedetomidine in arthroscopic knee surgeries under local anesthesia: A prospective randomized study

Background
An intra-articular injection is considered the leading method for postoperative analgesia after knee surgery. Dexmedetomidine has peripheral and central analgesic effect. The study was conducted to compare between the analgesic effect of intra-articular and intravenous dexmedetomidine in arthroscopic knee surgery.
Methods
One hundred patients underwent elective arthroscopic knee surgery had randomly allocated into two equal groups. the patients had received 1µg/kg dexmedetomidine added to local anesthetic bupivacaine intra-articularly while : the patients had received 1µg/kg dexmedetomidine added to 20ml saline over 10min starting with local intra-articular anaesthesia. Pain VAS, heart rate, mean arterial blood pressure, total requirement for analgesic, the first request for it, and first time to mobilize within the first 24h were assessed.
Results
The VAS were significantly lower in IA group at 4 and 6h during rest and at 4, 6, 12h during motion, Also, the duration of first analgesic request was significantly prolonged in IA group than IV group (11h ± 2.2 vs 9.2h ± 3.2, respectively) (p value .001). Moreover, the total analgesic consumption was significantly lesser IA group compared with that in IV group (87 ± 27.7mg Vs 108 ± 37.6mg, respectively) (p value .002). No postoperative adverse effects were recorded.
Conclusion
Intra-articular dexmedetomidine when added to local anaesthesia improves the postoperative analgesic profile with decrease the needs for postoperative analgesia and prolong the time for analgesic request.