Intra-articular Adjuvant Analgesics following Knee Arthroscopy: Comparison between Single and Double Dose Dexmedetomidine and Ropivacaine A Multicenter Prospective Double-blind Trial

Objective: Knee arthroscopy is a commonly performed orthopedic procedure. Post-operatively, adequate pain relief reduces the surgical stress response and patient's morbidity and facilitates rehabilitation. The analgesic effect of dexmedetomidine (2 mu g/kg body weight) as an adjunct to ropivacaine in knee arthroscopic knee procedures was studied to determine whether this would achieve longer post-operative analgesia and whether the study dosage of dexmedetomidine was safe and free of adverse effects. Patients and Methods: In a multicenter prospective double blind trial of sixty patients undergoing knee arthroscopic procedures, patients were randomly assigned to three groups: Group R, receiving intra-articular ropivacaine (20 mL); Group D1 (18 mL ropivacaine, dexmedetomidine 1 mu g/kg body weight); and Group D2 (18 mL ropivacaine, dexmedetomidine 2 mu g/kg). Results: Group D2 had significantly lower pain scores for the first 12 postoperative hours than Group D1 and Group R. Time to first analgesic requirement was longest in Group D2 (757.30 +/- 207.68 min), followed by Group D1 (433.2 +/- 54.3 min) and Group R (311.80 +/- 61.56 min); these differences were significant (P < 0.05). Total analgesic requirement was significantly lower in Group D2 (82.50 +/- 48.05 mg; P < 0.05). Intensity of pain was significantly less in Group D2 in the third (P < 0.01) and sixth hours (P < 0.05). Conclusion: Intra-articular dexmedetomidine (2 mu g/kg) has superior analgesic efficacy, delayed the first postoperative requirement for analgesia and decreasing the need for postoperative analgesics with no major adverse effects.