Taha Ahmed M, Mohanan Manjusha, Orduna Sebastian, Alalwi Ahmed F, Badr Mohamed I, Abd-Elmaksoud Ahmed M
Department of Anaesthesia, Healthpoint Hospital, Abu Dhabi, UAE.
Department of Anaesthesia, Ain Shams University, Cairo, Egypt.
Indian J Anaesth. 2025 Feb;69(2):214-219. doi: 10.4103/ija.ija_806_24. Epub 2025 Jan 29.
The femoral nerve (FN) is commonly blocked using ropivacaine to provide postoperative analgesia after knee surgery. However, the minimal required concentration has not yet been defined. The aim of this study was to estimate the minimal ropivacaine concentration required to achieve adequate analgesic FN block in 90% of cases (EC).
This study included 50 patients who were scheduled for knee ligament reconstruction under combined nerve block and general anaesthesia. The FN block was performed using 15 mL of ropivacaine with varying concentrations and considered adequate when associated with pain-free recovery. The sciatic, obturator, and lateral femoral cutaneous nerves were blocked to negate other knee pain generators, and their block success was confirmed. We used the biased-coin design up-down sequential method where the adequacy of an FN block altered the ropivacaine concentration used for the next block. The adequacy of the analgesic block or lack of it was analysed to calculate the analgesic EC. The quadriceps motor power and morphine requirement were also recorded.
The recommended analgesic ropivacaine EC was 0.05% w/v. The associated quadriceps weakness and morphine requirement were minimal.
FN block using ropivacaine 0.05% w/v may provide adequate analgesia in 90% of patients.
在膝关节手术后，常用罗哌卡因阻滞股神经（FN）以提供术后镇痛。然而，所需的最低浓度尚未明确。本研究的目的是估计在90%的病例中实现充分镇痛性股神经阻滞所需的罗哌卡因最低浓度（EC）。
本研究纳入50例计划在联合神经阻滞和全身麻醉下进行膝关节韧带重建的患者。使用15毫升不同浓度的罗哌卡因进行股神经阻滞，当与无痛恢复相关时认为阻滞充分。对坐骨神经、闭孔神经和股外侧皮神经进行阻滞以排除其他膝关节疼痛来源，并确认其阻滞成功。我们采用偏倚硬币设计的上下序贯法，其中股神经阻滞的充分性会改变用于下一次阻滞的罗哌卡因浓度。分析镇痛阻滞的充分性或缺乏情况以计算镇痛EC。还记录了股四头肌肌力和吗啡需求量。
推荐的镇痛性罗哌卡因EC为0.05%w/v。相关的股四头肌无力和吗啡需求量最小。
使用0.05%w/v罗哌卡因进行股神经阻滞可能在90%的患者中提供充分的镇痛。
