Continuous bupivacaine epidural analgesia was compared with conventional methods of systemic analgesic administration in the management of postoperative pain in 30 patients for 3 days following total knee replacement surgery. Patients given continuous epidural analgesia had significantly better pain relief (visual analogue scale, global evaluation), needed significantly fewer supplementary analgesics, and had significantly fewer side effects. In the epidural group, sensory block averaged six dermatomes on day 1 and four dermatomes on day 3. The number of patients with complete (or almost complete) motor block of the lower limbs decreased from eight on day 1 to five on day 3. The mean dosage of bupivacaine decreased from 21.0 +/- 5.7 (SD) mg/hr on day 1 to 15.1 +/- 8.5 mg/hr on day 3. No signs of accumulation of or toxic reactions to bupivacaine were seen.