Comparative study of intra-articular dexmedetomidine versus ketamine as adjuvant analgesics after knee arthroscopy

BackgroundKnee arthroscopy is one of the day case procedures which may be diagnostic or therapeutic. Postoperative analgesia is important for early ambulation and short hospital stay. This prospective randomized study was designed to compare the analgesic effect of intra-articular dexmedetomidine versus ketamine as adjuvant to bupivacaine following knee arthroscopy.Method75 patients ASA physical status I and II undergoing knee arthroscopy under general anesthesia were included in this study. Patients were divided into three groups according to intra-articular injected combination at the end of the arthroscopy. Group B/D received 25 ml 0.25% bupivacaine and dexmedetomidine 1 μg/kg, group B/K received 25 ml 0.25% bupivacaine and ketamine 1 mg/kg, and control group B received 25 ml 0.25% bupivacaine only. Postoperative pain using visual analogue score (VAS), the time to the first postoperative analgesic request, the total dose of postoperative analgesia during the first 24 h, and possible side effects were recorded.ResultsVisual analogue score (VAS) was significantly less in B/D group in comparison with B/K group after the 1st hour and thereafter. Also VAS was higher in B group compared to the other two groups (P < 0.05). Time to first postoperative analgesic request was longer in the B/D group (479.2 ± 34.9 min) than in B/K group (356.7 ± 39.2 min), but in both groups it was longer than in B group (312.4 ± 18.8 min), (P < 0.05).The total dose of postoperative analgesia (paracetamol consumption) during the first 24 h was significantly low in B/D group (758.0 ± 153.0 mg) compared to both B/K and B groups (1041.2 ± 178.6 mg and 1368.0 ± 227.2 mg) respectively (P < 0.05).ConclusionIntra-articular bupivacaine/dexmedetomidine provides better analgesia compared to bupivacaine/ketamine and both are superior to bupivacaine alone following knee arthroscopy.