The aim of the study was to find out whether addition of dexmedetomidine to lower concentration of ropivacaine preoperatively in femoral nerve block (FNB) would intensify analgesia and preserve quadriceps muscle strength after TKA.
We designed this study to evaluate whether dexmedetomidine added to lower concentration of ropivacaine for FNB can intensify analgesic effect and meanwhile reduce the possibility of lower limb (or quadriceps) weakness. Three groups were compared: 0.2% ropivacaine (H group), 0.1% ropivacaine (L group) and ropivacaine 0.1% added with 2 μg/kg dexmedetomidine (LD group).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
90
Dexmedetomidine added to lower concentration of ropivacaine for postoperative analgesia in FNB
ultrasound-guided femoral nerve block, a single bolous of 20 ml ropivacaine (concentration 0.2% for H group or 0.1% for L group) before surgery followed by continuous femoral nerve block using an infusion rate of ropivacaine 0.2% 5 ml/h for postoperative analgesia started right after surgery
All subjects received intravenous patient-controlled analgesia (IV-PCA) pumps to measure additional morphine consumption, which included 50 mg morphine in 50 ml saline: bolus 2 mg; lock out time, 15 minutes.
Department of Anesthesiology, First affiliated hospital of Sun Yat-Sen University
Guangzhou, Guangdong, China
Department of Anesthesiology, First affiliated hospital of Sun Yat-Sen University
Guangzhou, Guangdong, China
Change of manual muscle testing (MMT) over 72 hours postoperatively
The MMT grading was recorded from 0 to 5 to measure muscle strength at 6, 12, 24, 36, 48 and 72 hours after surgery.
Time frame: 0-72 hours postoperatively
Change of Timed Up and Go test (TUG) over 72 hours postoperatively
TUG test was used to assess the patient's mobility that requires both balance and static. It was measured at 24, 48 and 72 hours after surgery.
Time frame: 0-72 hours postoperatively
Change of numeric rating scales (NRS) over 72 hours postoperatively
NRS was used to evaluate postoperative pain control. They were measured at 6, 12, 24, 36, 48 and 72 hours after surgery.
Time frame: 0-72 hours postoperatively
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All the continuous femoral nerve block infusion regimes in the pump were connected to CFNB catheter, which contained only ropivacaine with different concentrations (ropivacaine 0.1% for L group and LD group; ropivacaine 0.2% for H group, 5 ml/h).