Stimulating Catheter With or Without Ultrasound Guidance

Phase 2 Study of Stimulating Catheter for Continuous Femoral Nerve Block in Total Knee Replacement

To study whether the combination of ultrasound guidance and stimulating catheter could reduce the time for needle and catheter insertion compared with using stimulating catheter alone. Secondary outcomes: analgesic effects after the surgery.

Inclusion Criteria:

• Elective primary total knee replacement surgery under neuraxial anesthesia ASA<=4
• Able to give informed consent
• Able to cooperate with sensory and motor testing of lower limb function

Exclusion Criteria:

• coagulopathy
• Allergy to local anaesthetic or postanalgesic rescue regimen
• Signs, symptoms or laboratory evidence of local infection or systemic sepsis
• No pre-existing neurological deficit (sensory or motor) affecting lower limb
• Patients with lower limb amputations