Total hip arthroplasty (THA) is a commonly performed surgical procedure, and its incidence continues to rise with the aging population. Effective postoperative analgesia facilitates early mobilization and accelerates recovery. The pericapsular nerve group (PENG) block provides analgesia to the anterior hip capsule by targeting the articular branches of the femoral, obturator, and accessory obturator nerves. However, due to the contribution of sacral plexus-derived nerves (quadratus femoris, superior gluteal, and inferior gluteal nerves) to posterior hip pain, anterior blocks alone may be insufficient.

This prospective study aims to compare the efficacy of preoperatively administered PENG block alone versus the combination of PENG and posterior hip pericapsular block (PHPB) in postoperative pain control after total hip arthroplasty. The primary outcome is postoperative pain intensity assessed by the Numerical Rating Scale (NRS). Secondary outcomes include the Quality of Recovery score (QoR-15), opioid consumption, manual muscle testing (MMT) results, time to mobilization, and block-related complications.

Total hip arthroplasty (THA) is a widely performed surgical procedure, and its incidence continues to increase with the aging population. It is an effective intervention to improve the quality of life in patients with advanced osteoarthritis or rheumatoid arthritis. Postoperative pain is one of the most common complications following THA. Effective postoperative analgesia facilitates early mobilization and accelerates recovery. Early mobilization within the first 24 hours after surgery has been shown to significantly reduce the length of hospital stay.

Regional anesthesia techniques for postoperative analgesia in hip surgery play a crucial role in pain management and recovery. International pain management guidelines recommend multimodal analgesic protocols for elective total hip arthroplasty, emphasizing the role of peripheral nerve blocks as part of these strategies.

Current anatomical studies have demonstrated that the innervation of the hip joint capsule is derived from multiple nerves originating from the lumbosacral plexus. The density and distribution of this neural supply may vary among individuals depending on pelvic morphology, ethnicity, and sex. The anterior portion of the hip joint capsule is primarily innervated by articular branches of the femoral and obturator nerves, while the posterior aspect receives innervation from branches of the sciatic nerve, the superior gluteal nerve, and the nerve to quadratus femoris (NQF). The NQF, which provides significant sensory input to the posterior hip region, has become a key anatomical target for posterior hip-focused regional anesthesia techniques.

The pericapsular nerve group (PENG) block, first described by Girón-Arango et al., provides analgesia to the anterior hip capsule by blocking the articular branches of the femoral, obturator, and accessory obturator nerves. PENG block has been suggested to facilitate early mobilization and recovery compared to other anterior approaches. However, even with appropriate anterior blocks, posterior gluteal pain may persist in patients with hip pathology. This highlights the potential importance of targeting sacral plexus-derived nerves for comprehensive analgesia.

Recent research has shown that branches from the quadratus femoris nerve (NQF), superior gluteal nerve (SGN), and inferior gluteal nerve (IGN) contribute to the posterior capsule innervation of the hip joint. Regional anesthesia techniques targeting these posterior articular branches may enhance postoperative analgesia, promote early mobilization, and improve functional recovery. Consequently, the integration of sacral plexus-focused posterior blocks alongside anterior approaches is increasingly being emphasized in multimodal analgesia protocols for THA.

The combination of the posterior hip pericapsular block (PHPB) with the PENG block has been reported to provide balanced and effective analgesia across the entire hip capsule while preserving motor function.

The aim of this prospective study is to compare the efficacy of preoperatively administered PENG block alone versus the combination of PENG and posterior hip pericapsular block (PHPB) for postoperative pain control in patients undergoing total hip arthroplasty. The primary endpoint is postoperative pain intensity assessed using the Numerical Rating Scale (NRS). Secondary endpoints include the Quality of Recovery (QoR-15) score, opioid consumption, manual muscle testing (MMT) results, time to mobilization, and block-related complications.

Inclusion Criteria:

• Patients scheduled for elective total hip arthroplasty (THA) under spinal anesthesia
• ASA physical status I-II
• Age ≥18 years
• Body Mass Index (BMI) between 18-35 kg/m²
• Patients who provide written informed consent

Exclusion Criteria:

• Age <18 years
• ASA physical status ≥III
• Known allergy or contraindication to study medications (local anesthetics, opioids, etc.)
• Severe cardiac, renal, hepatic, or pulmonary failure
• Revision total hip arthroplasty
• Coagulopathy or anticoagulant use
• Local infection or neuropathic findings at the injection site
• Chronic inflammatory diseases or chronic corticosteroid use
• Diagnosed neuropsychiatric disorders
• Pregnancy or lactation
• Inability or unwillingness to read, understand, or sign the informed consent form
• Obesity (BMI >35 kg/m²)
• Failed spinal anesthesia or conversion to general anesthesia
• Active malignancy or patients receiving radiotherapy/chemotherapy
• Active systemic infection or ongoing antibiotic therapy (except prophylaxis)
• Contraindication to regional anesthesia techniques
• Chronic opioid or analgesic use for pain disorders
• History of intracranial mass, increased intracranial pressure, epilepsy, cerebrovascular accident, neuromuscular disease, or motor/sensory deficits

Adult patients aged 18 years and older, classified as ASA physical status I-II, scheduled for elective total hip arthroplasty under spinal anesthesia at Ankara Bilkent City Hospital. A total of 132 patients who meet the inclusion criteria and provide written informed consent will be enrolled in this single-center, prospective, randomized controlled trial.