The Analgesic Efficacy of the Ultrasound-Guided Femoral Articular Branch Block for Ambulatory Hip Arthroscopy

Hip arthroscopy is a surgical technique that is gaining popularity for its diagnostic and therapeutic role in the management of adult hip pain. This procedure is frequently associated with severe post-operative pain despite the practice of injecting the hip joint with local anesthetics at the end of the procedure and the use of intraoperative opioids. The ideal analgesic technique that provides adequate pain relief following this procedure has not been established yet.

There is evidence to suggest that a femoral nerve block (FNB) may provide clinically meaningful analgesia. The investigators have examined the benefits of FNB both retrospectively and prospectively in hip arthroscopy patients at Women's College Hospital (WCH). Both of our studies suggested modest benefits of the FNB in terms of controlling post-operative pain and reducing opioid consumption. However the majority of patients continued to experience moderate to severe post-operative pain and required significant amounts of opioid analgesics in the Peri-Anesthesia Unit (PAU), despite receiving the FNB.

Another regional anesthesia technique, the femoral articular branch block (FAB) has recently been proposed to collectively block the terminal femoral and accessory obturator nerve branches to the hip joint with a single injection, theoretically blocking most of the innervation relevant to hip arthroscopy while sparing the main femoral nerve branches to the quadriceps muscle. The investigators aim to demonstrate the analgesic benefits of FAB.

• Femoral Articular Branch Block (Procedure): Slow injection (3mL aliquots) of local anesthetic solution (20ml of Ropivacaine 0.5%) into the fascia above the iliopsoas muscle (located in the groove between the two bony landmarks - (1)anterior inferior iliac crest and (2)iliopubic eminence).This is done by ultrasound guidance.
• Placebo Block (Procedure): Subcutaneous injection of 1ml normal sterile saline

Primary outcomes

• Analgesic Consumption [24 hours postoperatively]: Postoperative cumulative oral morphine equivalent consumption during the first 24 hours will be the first primary outcome
• Quality of Life scores [24 hours postoperatively]: Quality of Recovery (QR15) scores at 24 hours will be the second primary outcome. QR15 is a measurement of quality of recovery after surgery and anesthesia that has been psychometrically tested and validated. Reporting of outcome measures on a scale of 0 to 10 (0=None of the time and 10=All of the time). There are a total of 40 items/questions.

Secondary outcomes

• Pain Assessment (VAS) [Up to 48 hours post-operatively and at 7-day mark]: Visual Analogue Scale(VAS) - Pain:Overall pain assessed at rest and on movement A continuous scale comprised of a 100mm (10cm) horizontal line, anchored by 2 verbal descriptions No Pain to Worst Pain
• Analgesic Consumption [Up to 48 hours following surgery]: Consumption intra-operatively, total in-hospital postoperative consumption, and time to first analgesic request in the first 24 hours, cumulative oral morphine equivalent
• Presence of Block-related complications [Up until one month following nerve block]: vascular puncture, hematoma formation, intravascular injection, epidural anesthesia-bilateral sensory block Presence/ absence of residual paresthesia or numbness over femoral, obturator, and lateral cutaneous nerves distribution
• Incidence of opioid-related side effects [Up until one month following nerve block]: nausea, vomiting, pruritus, sedation
• Patient Satisfaction with Analgesic Technique [One month after surgery]: A Patient Diary will be completed to assess overall satisfaction with analgesic technique
• Demographic Data [Day 1 - first 24 hours]: Patient demographics - There is no scale, just questions asked of the participant.
• Turn over time [after surgery up to discharge, assessed up to 24 hours]: PAU leaving time

Sex: All, ages: 18 Years to 60 Years

Inclusion Criteria:

* American Society of Anesthesiologists (ASA) physical classification system, ASA I-III patients
* 18 - 60 years of age
* Body Mass Index (BMI) <35 kg/m2

Exclusion Criteria:

* Pre-existing neurological deficits or peripheral neuropathy in the distribution of femoral, obturator, or lateral cutaneous nerves
* Local infection
* Contra-indication to regional anesthesia e.g. bleeding diathesis, coagulopathy
* Chronic pain disorders
* History of using over 30mg of oxycodone or equivalent per day
* Contraindication to a component of multi-modal analgesia
* Allergy to local anesthesia
* History of significant psychiatric conditions that may affect patient assessment
* Pregnancy
* Inability to provide informed consent
* Patient refusal of femoral articular branch block
* Revision arthroscopy surgeries

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• Richard Brull, MD, Principal investigator, Women's College Hospital, University of Toronto
• Daniel Whelan, MD, Principal investigator, Women's College Hospital, University of Toronto