The hip joint is the largest and one of the most stable joints in the human body. It bears the majority of the body's weight during both dynamic and static activities, making it highly susceptible to degenerative diseases, particularly in the elderly population. In advanced cases, total hip arthroplasty (THA) is often required-currently ranking as the second most common joint replacement procedure worldwide.

Despite its clinical success, it is estimated that 7-28% of patients experience chronic postoperative pain following THA. This persistent pain significantly impairs quality of life and is receiving growing attention from healthcare professionals. Evidence suggests that unmanaged acute surgical pain is a major risk factor for the development of chronic postoperative pain, underscoring the importance of effective perioperative analgesia. Given the adverse effects associated with opioids, regional anesthesia techniques are increasingly favored for pain management.

Among these, the fascia iliaca compartment block (FICB) has been widely used to reduce postoperative pain intensity, although it carries potential drawbacks such as motor weakness or a need for supplemental opioid use. Recent anatomical studies by Short et al. have identified the anterior capsule of the hip joint as being innervated by the pericapsular nerve group (PNG) including the obturator nerve, accessory obturator nerve, and femoral nerve. The anatomical accessibility of these nerves has enabled the development of the pericapsular nerve group (PENG) block, a motor-sparing regional anesthesia technique that offers targeted analgesia by delivering local anesthetics into the myofascial plane between the psoas muscle and the superior pubic ramus.

While both FICB and PENG blocks are widely used in total hip replacement surgeries, comparative evidence evaluating their efficacy remains limited. Therefore, this study aims to compare the analgesic effectiveness of FICB and PENG blocks during the preoperative and postoperative phases of total hip arthroplasty.

Inclusion Criteria:

• 40 years or older
• non-pathologic hip fractures
• underwent total hip arthroplasty (THA) or hemiarthroplasty at Ain Shams University Hospitals
• physical status I, II and III according to the American Society of Anesthesiologists (ASA) classification.

Exclusion Criteria:

• pathological fracture
• allergy to study drugs.
• ASA IV (a patient with severe systemic disease that is a constant threat to life)
• bleeding tendencies
• dementia or any mental disability
• having sepsis