A randomized single-blind, double-observer trial was performed to evaluate the efficacy of a new non-steroidal anti-inflammatory analgesic drug, ketorolac, in the treatment of post-orthopaedic surgery pain. Sixty patients with moderate to severe pain were studied; 30 patients were treated with ketorolac at a dose of 30 mg intramuscularly up to 4-times a day, whilst the other 30 patients received 0.3 mg buprenorphine intramuscularly up to 4-times a day. A significant reduction in the severity of the pain was recorded in both groups. Throughout the study, comparable efficacy was found between the two therapies although buprenorphine showed greater efficacy during the first 8 hours. Interestingly, the withdrawals due to adverse events were significantly less in the ketorolac group (p less than 0.001). This study, therefore, suggests that ketorolac may be a useful and more acceptable alternative to buprenorphine in the treatment of post-orthopaedic surgery pain