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 μg/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 μg/kg body weight); and Group D2 (18 mL ropivacaine, dexmedetomidine 2 μg/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 μg/kg) has superior analgesic efficacy, delayed the first postoperative requirement for analgesia and decreasing the need for postoperative analgesics with no major adverse effects.