Comparison of analgesic effects and postoperative cognitive function following total knee arthroplasty: continuous intravenous infusion of fentanyl vs. ultrasound-guided continuous femoral nerve block with ropivacaine.

ABSTRACT

OBJECTIVE: The purpose of this study was to compare the effects of continuous intravenous infusions (CII) of fentanyl by pumping and ultrasound-guided continuous femoral nerve block (CFNB) with ropivacaine in terms of analgesic effects and postoperative cognitive function following total knee arthroplasty. METHODS: The clinical data of 103 patients who underwent total knee arthroplasty were collected retrospectively and divided into group A (n = 51) receiving CII of fentanyl by pumping and group B (n = 52) receiving CFNB with ropivacaine. Mini-Mental State Examination (MMSE) scores, Visual analog scale (VAS) scores, knee joint flexion angle (KJFA), muscle strength, postoperative cognitive dysfunction (POCD), patient satisfaction, and adverse reactions of the two groups were compared. RESULTS: The muscle strength scores in group B gradually improved at 6-48 h as compared with at 4 hours after operation (P < 0.05). Compared with group A, patients in group B had greater active motion of KJFA at 4, 6, and 12 h after operation (P < 0.05). In contrast to group A, patients in group B had lower VAS scores at rest or active and passive motion at 4-48 h after operation (P < 0.05). The MMSE scores of group B were higher than those of group A at 1, 4, and 7 d after operation (P < 0.05). The incidence of POCD at 4 d after operation was 1.92% in group B, lower than that of 15.69% in group A (P < 0.05). The incidence of adverse reactions was 5.77% in group B, lower than that of 29.41% in group A (P < 0.05). The satisfaction scores of group B were higher than those of group A (P < 0.05). CONCLUSION: Compared with CII of fentanyl by pumping, ultrasound-guided CFNB showed superior analgesic effects following total knee arthroplasty, which should reduce the incidence of POCD and adverse reactions.