Bupivacaine/ketamine is superior to intra-articular ketamine analgesia following arthroscopic knee surgery

Centroneuraxial and parenteral administration of ketamine has been shown to produce analgesia. However, this analgesia is limited by adverse effects. The purpose of this study was to determine whether ketamine alone or in combination with bupivacaine provides superior pain relief after surgery in patients undergoing knee arthroscopy. Sixty patients (classified as ASA status I or II) under-going arthroscopic meniscus repair during general anesthesia were randomized to receive 1.0 mg x kg(-1) ketamine (Group K), 0.25% bupivacaine (Group B) or a combination of 1.0 mg x kg(-1) ketamine and 0.25% bupivacaine (Group BK) to a total volume of 20 mL by intra-articular route following surgery. Visual analogue score in the postanesthesia care unit at 0.5, 1, 2, 4, 6, 8, 12 and 24 hr after surgery, duration of analgesia and subsequent 24 hr consumption of rescue analgesic (dextroproxyphene/acetaminophen) were evaluated. The results showed significantly higher pain scores in Group K as compared to Group B and Group BK. The duration of analgesia was significantly shorter in Group K as compared to the other two groups (Group B = 5.7 +/- 0.8; Group BK = 5.1 +/- 1.1 vs Group K = 1.7 +/- 0.9 hr; P < 0.05). However, 24 hr consumption of analgesic was similar in the three groups. We conclude that intra-articular bupivacaine-ketamine combination provides better pain relief than intra-articular ketamine after day care arthroscopic knee surgery.