Analgesic efficacy of the intra-articular administration of high doses of morphine in patients undergoing total knee arthroplasty.

Background And Objectives: Although the efficacy of intraarticular (IA) morphine is still controversial, it has been shown that higher doses promote better results and consequently decrease postoperative analgesic consumption, characterizing a dose-dependent peripheral action. A controlled, randomized, double-blind study was undertaken to evaluate the efficacy of the intra-articular administration of 10 mg of morphine in patients undergoing total knee arthroplasty.

Methods: Fifty patients undergoing total knee arthroplasty were randomly divided into two groups: the treatment group received 10 mg (1 mL) of intra-articular morphine diluted in 19 mL of NS, while the control group received the intra-articular administration of 20 mL of NS, both after closure of the capsule at the end of the surgery.