BACKGROUND: Rehabilitation physical therapy after a total knee arthroplasy (TKA) is important for the functional prognosis of the surgery and the methods of postoperative analgesic control could have influence on physical therapy. Therefore we compared surgical outcome of TKA patients receiving intravenous patient-controlled analgesia (IPCA) and epidural patient-controlled analgesia (EPCA) for pain control. METHODS: Forty four patients scheduled for a TKA were randomly allocated into two groups. The IPCA group received intravenous PCA (fentanyl 30mu g/ml, ketorolac 3 mg/ml, 0.5 ml/15 min/0.5 ml) after general anesthesia and the EPCA group received epidural PCA (0.1% bupivacaine, fentanyl 3 microgram/ml, 3 ml/15 min/3 ml) after combined spinal epidural anesthesia for an operation. Pain score and side effects were checked at 6, 24, 48, and 72 hours after the operation. Range of motion (ROM) was evaluated at discharge, 1 and 3 months after the operation. RESULTS: The EPCA group showed better analgesia and ROM than the IPCA group but the advantage on ROM did not last up to the 3 month follow up. Nausea/vomiting and sedation was more in the IPCA group, and backache, paresthesia and motor eakness of the lower limbs were more in the EPCA group. However, all side effects were tolerable for the patients. There was 31.8% of epidural catheter dislodgement or occlusion. CONCLUSIONS: Better analgesia with epidural PCA resulted in a better functional prognosis, but more effort would be needed to manage an epidural catheter.