[Intra-articular bupivacaine and morphine for knee osteoarthritis analgesia. Comparative study.].

BACKGROUND AND OBJECTIVES Osteoarthritis is the most common joint disease among elderly people. This study aimed at comparing the analgesic effects of intra-articular bupivacaine and morphine in knee osteoarthritis patients. METHODS Thirty-nine patients were included in this randomized double-blind study and divided in two groups: G1 (n = 18) patients were given intra-articular 1 mg (1 mL) morphine diluted in 9 mL of 0.9% saline, while G2 (n = 21) received intra-articular 25 mg (10 mL) of 0.25% plain bupivacaine. Pain intensity was evaluated by numerical and verbal scale at 0, 30, 60 minutes and 7 days at rest and in movement. Evaluated parameters were analgesic supplementation requirement with paracetamol (500 mg), total analgesic dose throughout the study, analgesia duration and quality (according to patient). RESULTS From 39 patients, 31 have completed the study. There has been no significant difference in pain intensity at rest and in movement between groups in all studied moments. There has been no difference between groups in time between solution administration and need for analgesic supplementation. Mean paracetamol dose in the first day was 796 mg for G1 and 950 mg for G2; supplementation during the week was 3578 mg for G1 and 5333 mg for G2. CONCLUSIONS The analgesic effect of intra-articular 1 mg morphine and 25 mg of 0.25% plain bupivacaine was similar.