Total hip arthroplasty (THA) is one of the most common surgical procedures performed in elderly patients, with its main indication being end-stage osteoarthritis of the hip1. It is estimated that over 572,000 patients per year will undergo THA in the USA alone by 20301 and postsurgical pain associated with THA remains a significant issue. Postoperative pain is associated with delayed joint mobilization, ambulation, patient satisfaction and can often delay the patient's discharge home1.

Multimodal analgesia for the management of postoperative pain following THA is now standard of care2,3. It involves a combination of local anesthetic infiltration (LAI), peripheral nerve blocks (PNBs), analgesics such as non-steroidal anti-inflammatory drugs (NSAIDs), acetaminophen and/or other medications, including gabapentinoids and opioids. Using multiple analgesic modalities allows for an easier and faster recovery for THA patients and ultimately allows for reduction in postoperative narcotic use and it's associated negative side effects. Total hip arthroplasty can be performed under either general anesthesia, epidural anesthesia or most commonly under spinal anesthesia, with or without epidural morphine. The adjunctive use of LAI, pericapsular nerve group (PENG) block or suprainguinal fascia iliaca compartment block (FICB) for postoperative pain management is becoming more widespread, although evidence on their efficacy has been inconsistent4-8. As such, comparative evaluation of these adjuctive analgesic modalities is imperative to optimize postoperative pain management following THA.

Suprainguinal fascia iliaca compartment block (FICB) is a technique that involves injection of local anesthetics underneath the fascia of the iliacus muscle to block the femoral nerve, the lateral femoral cutaneous nerve and, possibly, the obturator nerve9. The pericapsular nerve group block (PENG) is a technique that involves injection of local anesthetic in the musculofascial plane between the psoas muscle and the superior pubic ramus. Evidence to date shows that FICB and PENG may be effective modalities to provide postoperative pain control following THA and could reduce opioid consumption10. The above procedures have been documented as safe and effective when performed by a qualified anesthetist but come with various risks (potential motor / sensory blocade especially) and associated cost. Alternatively, or in conjunction to the above procedures, the orthopedic surgeon can perform local anaesthetic infiltration (LAI) into the anterior pericapsular tissues. To date, no study has compared the efficacy of FICB, PENG block and LAI in a randomized study, therefore a preferred postoperative analgesic regimen has yet to be determined.

In this randomized trial, the investigators aim to evaluate postoperative pain and side effects related to pain control in patients who receive FICB versus LAI versus PENG block following THA. The investigators aim to compare these procedures between each other and assertain whether these techniques compare favourably to spinal anesthetic as a control group.

Inclusion Criteria:

• Adults (≥18 years old) who require an inpatient primary total hip arthroplasty under spinal anesthesia
• Written consent
• Any gender

Exclusion Criteria:

• Patients who require revision surgery
• Anesthesia other than spinal (general, epidural, other)
• Body mass index (BMI) > 45 kg/m2
• Allergies to study medication
• Previous fracture to affected area
• Previous surgery to the affected hip
• Diagnosis other than osteoarthritis (avascular necrosis, significant deformity such as post-Perthes, slipped capital femoral epiphysis, dysplasia classified as Crowe 3 or 4, or other diagnoses causing significant deformity of the femoral head or acetabulum)
• THA for hip fractures
• Patients taking daily opiod analgesics pre-operatively
• Anesthetist on day of surgery who does not perform FICB and PENG and no alternate anesthetist available to perform the block
• Patients who do not understand, read or communicate in either French or English