PENG vs PHPB for Hip Arthroplasty Analgesia

Postoperative Analgesic Effectiveness of Pericapsular Nerve Block (PENG) and Posterior Hip Pericapsular Block (PHPB) in Hip Arthroplasty

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.

Study Overview

• Status: Active, not recruiting
• Conditions: PENG Block; Hip Arthroplasty, Total; QoR-15; Numeric Rating Scale
• Intervention / Treatment: Procedure: PENG Block; Procedure: PENG Block and Posterior Hip Pericapsular Block

Detailed Description

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.

• Study Type: Observational
• Enrollment (Actual): 127

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Çankaya
    • Ankara, Çankaya, Turkey (Türkiye), 06800
      • Ankara Bilkent City Hospital Departmant of Anesthesiology and Reanimation, Ankara,Çankaya

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

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.

Description

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

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
PENG Group; The group that will receive the preoperative Pericapsular Nerve Group (PENG) block	Procedure: PENG Block; Patients in this group will also undergo elective total hip arthroplasty (THA) under spinal anesthesia.A preoperative Pericapsular Nerve Group (PENG) block will be performed under ultrasound guidance using 20 mL of 0.25% bupivacaine. The injection will be administered between the psoas tendon and the iliac bone to block the articular branches of the femoral, obturator, and accessory obturator nerves, providing analgesia to the anterior hip capsule.
PENG + PHPB Group; The group that will receive the preoperative Pericapsular Nerve Group (PENG) block and Posterior Hip Pericapsular Block (PHPB)	Procedure: PENG Block and Posterior Hip Pericapsular Block; Patients in this group will also undergo elective total hip arthroplasty (THA) under spinal anesthesia.A preoperative Pericapsular Nerve Group (PENG) block will be performed under ultrasound guidance using 20 mL of 0.25% bupivacaine. The injection will be administered between the psoas tendon and the iliac bone to block the articular branches of the femoral, obturator, and accessory obturator nerves, providing analgesia to the anterior hip capsule. In addition to the PENG block, a Posterior Hip Pericapsular Block (PHPB) will be performed under ultrasound guidance using 20 mL of 0.25% bupivacaine. The local anesthetic will be injected between the piriformis muscle and the ischiofemoral ligament to target the posterior articular branches of the quadratus femoris, superior gluteal, and inferior gluteal nerves. The combined PENG + PHPB approach aims to provide comprehensive analgesia of both the anterior and posterior hip capsule while preserving motor function.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Postoperative pain	Postoperative pain will be assessed using the Numeric Rating Scale (NRS; 0 = no pain, 10 = worst imaginable pain) at rest and during movement at 0, 2, 6, 8, 12, 24, 36, and 48 hours after surgery. The NRS scores will be compared between the two study groups (PENG vs. PENG + PHPB) to evaluate the effectiveness of the blocks in postoperative analgesia following total hip arthroplasty.	Up to 48 hours postoperatively

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
QUALİTY OF RECOVERY-15	The quality of postoperative recovery will be assessed using the validated 15-item Quality of Recovery questionnaire (QoR-15). The total score ranges from 0 (very poor recovery) to 150 (excellent recovery). The score will be measured preoperatively and at 24 and 48 hours postoperatively to compare recovery quality between the two groups.	Preoperative, 24, and 48 hours postoperatively
MANUEL MUSCLE TEST	Quadriceps muscle strength will be evaluated using the Manual Muscle Test (MMT) scale at 6, 12, and 24 hours after surgery. The MMT scale ranges from 0 (no contraction) to 5 (normal strength). A score <3 indicates quadriceps weakness.	6, 12, and 24 hours postoperatively
Rescue analgesic	The time from the end of surgery to the patient's first request for rescue analgesia will be recorded. Rescue analgesia consists of intravenous tramadol 100 mg administered if the Numeric Rating Scale (NRS) score is ≥ 4. This measure will compare the analgesic duration provided by the two blocks (PENG vs. PENG + PHPB).	0-48 hours postoperatively
Postoperative Nausea and Vomiting (PONV)	The presence of postoperative nausea and/or vomiting will be recorded during the first 48 hours following surgery.	0-48 hours postoperatively
Length of Hospital Stay	The duration of hospitalization will be measured from the day of surgery to discharge.	Up to discharge (approximately 3-5 days postoperatively)

Collaborators and Investigators

• Sponsor: Ankara City Hospital Bilkent
• Investigators: Study Director: Abdulkadir But, Professor, Ankara Bilkent City Hospital Departmant of Anesthesiology and Reanimation,Ankara,Çankaya

Publications and helpful links

General Publications

• Atalay YO, Ciftci B, Tekin B, Ansen G, Sakul BU, Cacan MA, Azboy I, Yilmaz B, Alici HA. A Case Series of Deep Subgluteal Block: A New Block Targeting the Missed Portion of the Hip for Analgesia After Total Hip Replacement. A A Pract. 2024 Sep 9;18(9):e01848. doi: 10.1213/XAA.0000000000001848. eCollection 2024 Sep 1.
• Duan L, Li J, Chen Z, Wen T, He J, Zhang A. Posterior Hip Pericapsular Block (PHPB) with pericapsular nerve group (PENG) block for hip fracture: a case series. BMC Anesthesiol. 2024 Oct 1;24(1):352. doi: 10.1186/s12871-024-02731-2.
• Vermeylen K, Van Aken D, Versyck B, Casaer S, Bleys R, Bracke P, Groen G. Deep posterior gluteal compartment block for regional anaesthesia of the posterior hip: a proof-of-concept pilot study. BJA Open. 2023 Feb 15;5:100127. doi: 10.1016/j.bjao.2023.100127. eCollection 2023 Mar.

Study record dates

Study Major Dates

• Study Start (Actual): December 1, 2025
• Primary Completion (Actual): April 15, 2026
• Study Completion (Estimated): July 1, 2026

Study Registration Dates

• First Submitted: November 24, 2025
• First Submitted That Met QC Criteria: November 24, 2025
• First Posted (Actual): December 4, 2025

Study Record Updates

• Last Update Posted (Actual): May 6, 2026
• Last Update Submitted That Met QC Criteria: May 5, 2026
• Last Verified: October 1, 2025

More Information

Terms related to this study

• Other Study ID Numbers: E2-25-12993

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No