The analgesic efficacy of continuous femoral nerve block and continuous intravenous analgesia after total knee replacement: an one-year-follow-up study

Objective To compare the analgesic effects of continuous femoral nerve block analgesia (CFNB) and intravenous patient-controlled analgesia (PCIA) after total knee replacement surgery, and evaluate the knee function in one-year-follow-up study postoperatively. Methods From November 2008 to October 2009,60 patients undergoing unilateral total knee replacement were randomized into two groups, 30 cases each (n=30). PCIA was given for postoperative analgesia and CFNB as another way. All patients received spinal anesthesia combined with epidural anesthesia. In the perioperative period, Visual analogue scale (VAS) was used to evaluate perioperative pain score. Total amount of morphine, muscle strength of limb, the time of first ambulation and analgesic associated complications were observed and recorded. All the patients were followed up for one year, using Knee Society scoring system (KSS) to assess knee function. Results In six, 12, 24, 36, 48 hours postoperative resting state, pain score (VAS) of CFNB group was significantly lower than that of PCIA group (P0.05). During the continuous passive movement (CPM) of knee postoperatively at 24 and 48 hours, the dosage of cumulative morphine of CFNB group was significantly lower than that of CIA group (P0.05). Adverse reactions such as lethargy, nausea and vomiting were also fewer in the CFNB group. No significant difference was found in knee function evaluation of two groups at one year follow-up (P0.05). Conclusions CFNB has superior early analgesic effect to PCIA in total knee replacement surgery, as well as fewer adverse reactions,better knee function recovery, and higher patient satisfaction. CFNB is a safe, practical and effective method for analgesia after TKA.