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.

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