CONTINUOUS EXTRADURAL INFUSION OF ROPIVACAINE FOR PREVENTION OF POSTOPERATIVE PAIN AFTER MAJOR ORTHOPEDIC-SURGERY

We studied 151 patients undergoing total hip or knee arthroplasty, or cruciate ligament reconstruction in a multicentre study in Australia a nd New Zealand. Patients were openly allocated randomly to one of five treatment groups or to a control group. General anaesthesia was induc ed after introduction of extradural block with 0.5% ropivacaine. After surgery, patients received an extradural infusion of 0.2% ropivacaine at 6, 8, 10, 12 or 14 ml h(-1) or received no postoperative extradura l infusion (control group). All patients had access to i.v. PCA morphi ne for supplementary analgesia. Morphine consumption was lower in all treatment groups compared with the control group, decreasing with incr easing ropivacaine infusion rate. Median VAS scores were lower in all ropivacaine infusion groups compared with the control group for the fi rst 10 h of the study; however by the end of the study, VAS scores wer e similar in all groups. The higher ropivacaine infusion rates caused a slower convergence of spread of the initial sensory block and a high er degree of motor block. The overall incidence of side effects was si milar, with the exception of a higher incidence of urinary retention a nd hypotension in the groups receiving the higher rates of ropivacaine . The quality of treatment scores were similar for all treatment group s.