Dexmedetomidine as Adjuvant for FNB in TKA

Comparison of Dexmedetomidine as Adjuvant to Different Concentrations of Ropivacaine for Femoral Nerve Blockade in Patients Undergoing Total Knee Arthroplasty

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).

Inclusion Criteria:

• ASA I-II
• scheduled for total knee arthroplasty

Exclusion Criteria:

• refusal to participate in this study
• unicompartmental knee arthroplasty
• BMI > 35 kg/m2
• congnitive or phychiatric history
• refusal of general anesthesia
• contraindication to laryngeal mask airway insertion
• contraindication to peripheral nerve block (localized infections, sepsis, coagulopathy, bleeding diathesis or preexisting lower extremity neurological abnormality)
• allergy to the drugs used