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

Objective To investigate the effects of ultrasound-guided continuous femoral nerve block(FNB) with bupivacaine for postoperative pain relief of patients after unilateral total knee arthroplasty(TKA).Methods Forty-six patients underwent unilateral TKA were equally randomized into two groups.The patients in group A were treated by ultrasound-guided patient-controlled nerve analgesia(PCNA) of FNB with bupivacaine and those in group B were given patient-controlled epidural analgesia(PCEA) with morphine and bupivacaine.PCNA or PCEA lasted for two days.VAS pain score under rest and passive movement,muscle strength and side effects were recorded during analgesia.Results The VAS pain scores at rest had no significant difference between two groups,which during passive movement at 48 h were obviously lower in group A than those in group B(P0.01).The muscle strength grades had no statistical difference between two groups.The incidence of urinary retention was lower in group A than that in group B(4.3% vs.30.4%)(P0.01).Conclusion Ultrasound-guided PCNA of continuous FNB is better than PCEA for postoperative analgesia with less side effects in the patients after TKA.