Background:Arthroscopic knee surgery is commonly performed as an outpatient procedure and is often associated with postoperative pain.Objectives:We aimed to compare the effects of intra-articular levobupivacaine-tenoxicam-tramadol and levobupivacaine-tenoxicam-morphine combinations on postoperative pain in patients undergoing elective arthroscopic knee surgery.Materials and Methods:A total of 90 ASA I-II patients undergoing elective arthroscopic meniscectomy under general anesthesia were enrolled. The participants were randomly allocated to three groups to receive the following intra-articular medications after completion of the surgery and before deflation of the tourniquet: Group S, 20 mL of saline; Group T, 35 mg of levobupivacaine, 20 mg of tenoxicam, and 100 mg of tramadol in 20 mL saline; and Group M, 35 mg of levobupivacaine, 20 mg of tenoxicam, and 4 mg of morphine in 20 mL saline. Visual analogue scale values at rest (VASr) and at active flexion of knee (VASa) at postoperation hours 1, 2, 4, 8, 12, and 24, duration of analgesia, total analgesic consumption, and number of rescue analgesia at 24 hours were evaluated.Results:VASr and VASa were significantly higher in group S in comparison to other groups (P < 0.05). Duration of analgesia was significantly longer in Group T and Group M than in Group S (P < 0.05). The difference between group T and group M was also significant (P < 0.05). Number of rescue analgesia and total analgesic consumption at postoperative hour 24 was significantly fewer in group M compared with other groups (P < 0.05).Conclusions:Intra-articular levobupivacaine-tenoxicam-morphine combination provides effective pain relief, longer analgesic duration, and less analgesic requirement when compared with intra-articular levobupivacaine-tenoxicam-tramadol combination and saline after knee arthroscopic surgery.