This randomized double-blind study compared the analgesic efficacy and tolerability of intramuscular lornoxicam and tramadol in 76 patients with moderate to unbearable pain following arthroscopic reconstruction of the anterior cruciate ligament using the patella bone-tendon-bone technique. Patients receiving a single dose of lornoxicam 16 mg experienced significantly greater total pain relief than patients receiving tramadol 100 mg over the following 8 hours. Lornoxicam had greater analgesic efficacy than tramadol in patients with moderate baseline pain but was of equivalent efficacy in those with severe/unbearable baseline pain. Fewer patients in the lornoxicam group required rescue medication (58% vs. 77%, respectively). Patients' global impression of efficacy showed lornoxicam to be superior to tramadol with 82% and 49% of patients, respectively, rating treatment as good, very good, or excellent. Following multiple-dose administration of lornoxicam (8 mg tid) or tramadol (100 mg tid) for 3 days, efficacy profiles similar to those following a single dose were obtained. Thus, slightly fewer patients in the lornoxicam group required rescue medication, and patients' global impression of efficacy again favored lornoxicam. Adverse events were reported by 38 of the 76 patients and were mainly mild to moderate in severity. Significantly fewer patients reported one or more adverse events with lornoxicam than with tramadol (14 vs. 24, respectively). Thus, intramuscular lornoxicam offers a useful alternative to tramadol for the treatment of moderate to severe postoperative pain.