Fascia Iliaca Block with and without ultrasound for knee surgery.

After informed consent, patients will be assigned, by using a computer-generated block randomization, to either group 1 - ultrasound guided fascia iliaca block, or group 2 - fascia iliaca block with loss of resistance blind technique. Patient will receive routine general anaesthetic for the operation as per the discretion of the anaesthetist. Allowable analgesics include alfentanil/ fentanyl for induction. After the patient is asleep, Group 1 patient will then have a fascia iliaca block placed with ultrasound assistance. The fascia iliaca and the iliacus muscle are identified. An 18 gauge Touhy needle will be inserted under the fascia iliaca with ultrasound guidance. Group 2 patient will have the fascia iliaca block performed by anatomical landmark technique alone. The line from the anterior superior iliac spine and pubic tubercle is drawn. The insertion point is at the lateral 1/3 and medial 2/3 and 1cm caudad to the line drawn. Again an 18 gauge Tuohy needle will be inserted using 2-pop loss of resistance technique. All blocks will be performed by anaesthetists who are proficient at blocks without ultrasound, and who have been trained in the use of ultrasound for vascular access or other nerve blocks. The investigator will be present if required to provide guidance. For both groups, a total of 0.5ml/kg 0.5% ropivacaine (maximum of 40ml) will be injected through the Tuohy needle in 5ml aliquots after negative aspiration. Morphine can be administered during the operation as per the discretion of the anaesthetist. Non-steroidal anti-inflammatory drugs (NSAIDS) and tramadol will not be allowed intra-operatively or post-operatively for 48hours. Paracetamol will be given strictly 6-hourly (QID). A morphine patient controlled analgesia pump will be commenced post-operatively. A blinded research nurse or investigator would then collect the data required from this study.