Yang Xiaoyu, Kang Wenbin, Xiong Wei, Lu Dihan, Zhou Zhibin, Chen Xi, Zhou Xue, Feng Xia
Department of Anesthesiology, The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, People's Republic of China.
Department of Anesthesiology, Tianjin Medical University Cancer Institute and Hospital, Tianjin, People's Republic of China.
J Pain Res. 2019 Dec 17;12:3355-3363. doi: 10.2147/JPR.S217283. eCollection 2019.
Femoral nerve block (FNB) has been considered as an excellent analgesic modality in total knee arthroplasty (TKA) pain control. However, relatively high concentration of ropivacaine could lead to quadriceps muscle weakness and increase the risk of postoperative falls.
This double-blinded randomized controlled study was designed to investigate the effect of a combination of dexmedetomidine with a lower concentration of ropivacaine on quadriceps muscle strength and analgesic effect in FNB.
A total of 90 patients scheduled for TKA were randomized to receive continuous FNB postoperatively using 0.2% ropivacaine (H group), 0.1% ropivacaine (L group) or 0.1% ropivacaine combined with 2 μg/kg dexmedetomidine (LD group). Meanwhile, intravenous patient-controlled analgesia with morphine was administered to patients. The primary endpoint was the strength of quadriceps muscle evaluated by manual muscle testing (MMT) and Timed Up and Go test (TUG). The secondary endpoint was the pain scores and morphine consumption among different groups.
For MMT, LD group showed higher quadriceps muscle strength than the other two groups (<0.05) at 12 hrs postoperatively. TUG test was conducted to measure the walking ability, and showed that scores were significantly better in LD group than those in H group and L group (<0.05) at 24 and 48 hrs postoperatively. There was no significant difference between H and LD group in the numeric rating scales (NRS) scores both at rest and at 45° flexion. The total morphine consumption in L group was significantly higher than in H or LD group (<0.001).
Collectively, the addition of dexmedetomidine 2 μg/kg to 0.1% ropivacaine preoperatively would preserve quadriceps muscle strength with satisfactory analgesia in patients undergoing TKA. (This study was registered at ClinicalTrials.gov, identifier NCT03658421).
股神经阻滞（FNB）被认为是全膝关节置换术（TKA）疼痛控制中一种出色的镇痛方式。然而，相对高浓度的罗哌卡因可能导致股四头肌无力，并增加术后跌倒的风险。
本双盲随机对照研究旨在探讨右美托咪定与较低浓度罗哌卡因联合应用对FNB中股四头肌力量和镇痛效果的影响。
总共90例计划行TKA的患者被随机分为三组，术后分别接受持续FNB，使用0.2%罗哌卡因（H组）、0.1%罗哌卡因（L组）或0.1%罗哌卡因联合2μg/kg右美托咪定（LD组）。同时，对患者实施吗啡静脉自控镇痛。主要终点是通过徒手肌力测试（MMT）和计时起立行走测试（TUG）评估的股四头肌力量。次要终点是不同组之间的疼痛评分和吗啡用量。
对于MMT，术后12小时LD组的股四头肌力量高于其他两组（P<0.05）。进行TUG测试以测量行走能力，结果显示术后24小时和48小时LD组的得分显著优于H组和L组（P<0.05）。静息和45°屈曲时的数字评分量表（NRS）评分在H组和LD组之间无显著差异。L组的吗啡总用量显著高于H组或LD组（P<0.001）。
总体而言，术前在0.1%罗哌卡因中添加2μg/kg右美托咪定可在TKA患者中保留股四头肌力量并提供满意的镇痛效果。（本研究已在ClinicalTrials.gov注册，标识符为NCT03658421）
