Application of continuous femoral nerve block guided by ultrasound for analgesia after total knee arthroplasty

Objective To assess the clinical effect of ultrasound-guided continuous femoral nerve block(CFB) on analgesia after total knee arthroplasty(TKA).Methods Forty patients scheduled for unilateral TKA under combined intravenous-inhalation anesthesia were randomly divided into CFB group(the test group) and patient-controlled intravenous analgesia(PCIA) group(the control group).There were 20 patients in each group.The postoperative visual analog score(VAS) at still and on movement,overall satisfaction of the patients,intravenous morphine consumption and side effects associated with postoperative analgesia were recorded during the first 72 h postoperatively.Results VAS scores at still and on movement were significantly lower in the test group than those in the control group(P0.01).Postoperative morphine consumption at different time points and total morphine consumption over 72 h were significantly less in the test group than those in the control group(P0.05 or P0.01).The muscle strength of quadriceps femoris in the test group was significantly weaker than that in the control group 1 h,2 h and 4 h after the surgery(P0.01).The incidence of side effects in the test group was significantly lower than that in the control group(40% vs.85%,P0.01).The patients in the test group were more satisfied than those in the control group(95% vs.10%,P0.01).Conclusion Ultrasound-guided CFB can effectively relieve pain,decrease the opioid consumption and the side effects associated with opioids after TKA,and improve the patients' satisfaction rate.