 METHODS: Thirty-nine patients with pain for more than 3 months and an intensity higher than 3 on a numerical scale zero to 10 were included. G1 patients received 1 mg 1 ml morphine diluted in 9 ml saline by the intra-articular route, and G2 patients received 25 mg 10 ml 0.25 bupivacaine without epinephrine. Pain was assessed on a numerical scale and knee flexion and extension angles were measured after administration of the drugs at rest and during movement. The total amount of analgesic complementation with 500 mg paracetamol was also determined. 