Efficacy of different lower extremity nerve block combined with general anesthesia in total knee arthroplasty in elderly patients

Objective To compare the efficacy of different lower extremity nerve block combined with general anesthesia in total knee arthroplasty in elderly patients. Methods Forty-eight ASAⅠ- Ⅱ patients aged 60- 78 years weighing 51- 83 kg undergoning elective total knee arthroplasty under general anesthesia were selected,and randomly divided into three groups( n = 16) : general anesthesia group( groupⅠ),femoral nerve block group( groupⅡ),femoral nerve block combined with sciatic nerve block group( group Ⅲ).Operations were performed under combined intravenous- inhalational anesthesia with endotracheal tube. The patients in group Ⅱ and group Ⅲ received nerve block guided by nerve stimulator before induction of anesthesia. All the patients were given postoperative patient- controlled intravenous analgesia with sufentanil. Heart rate( HR) and mean arterial pressure( MAP) were recorded before anesthesia( T1),at the beginning of surgery( T2),60 min after the beginning of surgery( T3) and the end of operation( T4). The time of recovery and incidence of emergence agitation,visual analogue scale( VAS)( rest pain /movement pain) at postoperative 6 h,12 h and 24 h were evaluated,and sufentanil consumption within 12 h and 24 h were also recorded. Results HR and MAP at T2,T3,T4 were significantly lower in groups Ⅱ and Ⅲ than those in groupⅠ( P 0. 05). Compared with groupⅠ,the time of recovery and incidence of emergence agitation decreased in group Ⅱ,Ⅲ( P 0. 05). VAS( rest pain and movement pain) was significantly higher in groupⅠ than in group Ⅱ and group Ⅲ( P 0. 05). VAS( movement pain) was significantly lower in group Ⅲ than in group Ⅱ( P 0. 05). Compared with group Ⅰ,the consumption of sufentanil was significantly decreased within 12 h and 24 h after operation in group Ⅱ and group Ⅲ( P 0.05). Conclusion Combined lower extremity nerve block is superior to the general anesthesia in hemodynamics and postoperative analgesia for elderly patients undergoing total knee arthroplasty. Compared with femoral nerve block,femoral nerve block combined with sciatic nerve block is superior to femoral nerve block only in decreased pain score during mobilization for elderly patients undergoing total knee arthroplasty.