[Comparison of the influences of continuous femoral nerve block and patient controlled intravenous analgesia on total knee arthroplasty].

Objective: To assess the influences of continuous femoral nerve block (CFNB) and patient-controlled intravenous analgesia (PCIA) on postoperative pain scores,knee rehabilitation,and stress response after total knee arthroplasty (TKA).

Methods: Totally 32 adult patients scheduled for elective total knee arthroplasty were equally randomized into CFNB group or PCIA group. Intraoperative hemodynamics and fentanyl dose were recorded. Pain was assessed at rest and during continuous passive motion (CPM) using a visual analog scale at post-anesthesia care unit (PACU) and 4, 8, 12, 24, and 48 hours postoperatively. Morphine consumption was also recorded. As indicators of stress and inflammatory response,the leukocyte count, serum lactic acid, blood glucose, serum C-reactive protein (CRP), and serum cortisol were determined on admission, to operation room, immediately after skin incision, before extubation,on post-operation day 1 (POD1), and on POD2.

Results: CFNB group showed significantly lower heart rate compared with PCIA group 60 minutes and 90 minutes intraoperatively (Pü0.05). Intraoperative consumption of fentanyl was significantly lower in CFNB group (137.5∓44.4) μg than in PCIA group (264.1∓67.1) μg (Pü0.01). The CFNB group showed significantly lower VAS scores both at rest and during CPM compared with PCIA group at all time points (Pü0.05). Morphine consumption was significantly lower in CFNB group than in PCIA group at different time points (Pü0.05 or Pü0.01). The maximal continuous passive motion amplitude of CFNB group were significantly larger than that of PCIA group on POD1 [(55.0∓9.4) vs.(44.6∓9.9), P[(76.3∓11.0) vs. (67.5∓10.3), P<0.05]. The incidences of somnolence and nausea/vomiting in CFNB group were 37.5% and 37.5%, respectively,which were significantly lower than those of PCIA group (75.0% and 81.3%) (Pü0.05). Patient satisfaction scores on anesthesia and post-operative analgesia was significantly higher in CFNB group than in PCIA group (93.1∓7.9 vs. 79.1∓11.9, respectively) (Pü0.05).

Conclusion: After TKA,CFNB technique provides more stable intraoperative hemodynamics than PCIA, with better pain relief,faster postoperative knee rehabilitation,less side effects,and higher patient satisfaction.