PENG Block & PENG PRF (PENG-PRF)

Evaluation of the Clinical Effectiveness of Pericapsular Nerve Group (PENG) Block and Pulsed Radiofrequency Applications in Chronic Hip Pain

The primary aim of this study is to prospectively compare the effects of the pericapsular nerve group (PENG) block alone and the combination of PENG block with pulsed radiofrequency (PRF) on pain intensity in patients with chronic hip pain. As a secondary aim, the effects of both treatment modalities on hip function are intended to be evaluated using valid and reliable functional assessment scales. Through this study, it is aimed to demonstrate the clinical contribution of adding PRF to the PENG block and to identify a more effective and longer-lasting approach for the interventional treatment of chronic hip pain.

Study Overview

• Status: Recruiting
• Conditions: Osteoarthritis (OA) of the Hip
• Intervention / Treatment: Procedure: PENG Block Pulsed radiofrequency

Detailed Description

Chronic hip pain is a common clinical condition, particularly in the elderly, that significantly impairs quality of life and leads to functional limitation and dependence in daily activities. Chronic hip pain caused by degenerative, inflammatory, and mechanical conditions-most notably hip osteoarthritis-often remains inadequately controlled despite medical treatment, physical therapy, and rehabilitation. Although surgical interventions can be effective, they are not suitable for all patients due to advanced age, comorbidities, or surgical contraindications. Therefore, minimally invasive interventional pain management techniques have gained increasing importance in the treatment of chronic hip pain.

The nociceptive innervation of the hip joint primarily arises from the anterior capsule, which is mainly supplied by the sensory branches of the femoral, obturator, and accessory obturator nerves. Based on this anatomical rationale, the pericapsular nerve group (PENG) block is an ultrasound-guided technique that targets these sensory fibers to provide effective analgesia without causing motor blockade. Previous studies have shown that the PENG block reduces pain scores and improves functional mobility in both acute and chronic hip pain; however, its analgesic effect may be time-limited, requiring repeated applications in some patients.

Pulsed radiofrequency (PRF), unlike conventional thermal radiofrequency, aims to modulate nerve transmission without causing tissue destruction and may provide longer-lasting analgesia through neuromodulatory mechanisms. Recent evidence suggests that combining PRF with peripheral nerve blocks may prolong analgesic effects compared with nerve blocks alone. However, prospective studies directly comparing PENG block alone with PENG block combined with PRF in chronic hip pain are limited, highlighting the need for further investigation.

• Study Type: Observational
• Enrollment (Estimated): 84

Contacts and Locations

• Study Contact: Name: Ulku Sabuncu MD, Assoc. prof.; Phone Number: +905337085212; Email: sabuncuulku@gmail.com

Study Locations

• Turkey (Türkiye)
  • Ankara, Turkey (Türkiye), 06680
    • Recruiting
    • Ankara Bilkent City Hospital
    • Contact: Ulku Sabuncu Assoc. Prof.; Phone Number: 905337085212

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Non-Probability Sample

Study Population

18-80 years old with chronical hip pain

Description

Inclusion Criteria:

• Presence of chronic hip pain lasting at least 3 months
• Baseline Visual Analog Scale (VAS) score ≥ 4
• Clinical and/or radiological diagnosis of hip osteoarthritis
• Inadequate response to conservative treatments

Exclusion Criteria:

• Local or systemic infection at the intervention site
• Coagulopathy or inability to discontinue anticoagulant therapy
• Hip pain related to malignancy
• History of previous hip arthroplasty
• Severe neurological deficit
• Pregnancy or breastfeeding

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

Group PENG; The initial step in patients diagnosed with chronic hip pain is a diagnostic intervention, namely the application of a pericapsular nerve group (PENG) block. In patients who benefit from the diagnostic block-defined as a reduction of 50% or more in VAS scores following the procedure-pulsed radiofrequency (PRF) treatment is added as a second-stage intervention. This stepwise approach reflects standard clinical practice, and both procedures are commonly used in clinical praqctice for the management of chronic hip pain. However, the available evidence in the literature on this approach is largely limited to case reports and retrospective case series. The aim of the present study is to document and share the clinical outcomes of this treatment strategy routinely applied in clinical practice.

Procedure: PENG Block Pulsed radiofrequency; This intervention consists of a stepwise, two-stage treatment protocol routinely applied in our clinical practice for the management of chronic hip pain. In the first stage, all patients undergo an ultrasound-guided pericapsular nerve group (PENG) block as a diagnostic and therapeutic procedure. Pain intensity is assessed using the Visual Analog Scale (VAS) following the diagnostic block. Only patients who demonstrate a clinically meaningful response, defined as a reduction of 50% or greater in VAS scores, proceed to the second stage of the intervention. In the second stage, pulsed radiofrequency (PRF) treatment is applied to the same target region in addition to the PENG block, aiming to achieve longer-lasting analgesia through neuromodulation without tissue destruction.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in pain intensity measured by the Visual Analog Scale (VAS, 0-10; higher scores indicate worse pain)	Pain intensity will be assessed using the Visual Analog Scale (VAS), a validated pain measurement tool ranging from 0 to 10, where 0 indicates no pain and 10 represents the worst pain imaginable.	baseline (pre-procedure) and at 1 week, 1 month, 3 months, and 6 months after the procedure.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Pain, Stiffness, and Physical Function Measured by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC, 0-96)	Pain, stiffness, and physical function were assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC; total score range 0-96, with higher scores indicating worse symptoms and functional limitation). The change in WOMAC total score from baseline to 1 month following pulsed radiofrequency (PRF) treatment was evaluated as a secondary outcome. Additional analyses included changes in WOMAC subscale scores (pain, stiffness, and physical function) at 1 week, 3 months, and 6 months post-intervention. A clinically meaningful improvement was defined as a ≥20% reduction in the total WOMAC score compared with baseline.	baseline (pre-procedure) and at 1 week, 1 month, 3 months, and 6 months after the procedure.
Change in Hip Function Measured by the Harris Hip Score (HHS, 0-100)	Hip pain and functional status were evaluated using the Harris Hip Score (HHS; total score range 0-100, with higher scores indicating better hip function). The HHS assesses four domains: pain, function (activities of daily living and gait), absence of deformity, and range of motion. The change in total HHS from baseline to 1 month after pulsed radiofrequency (PRF) treatment was analyzed as a secondary outcome. Additional assessments were performed at 1 week, 3 months, and 6 months post-intervention to evaluate the sustainability of functional improvement. A clinically meaningful improvement was defined as an increase of ≥10 points in the total HHS compared with baseline.	Baseline (pre-procedure), 1 week, 1 month (primary functional endpoint), 3 months, and 6 months after pulsed radiofrequency (PRF) treatment.
Secondary Outcome: TAnalgesic Use	The following parameters were evaluated as secondary outcomes: Analgesic consumption: Changes in daily analgesic dose and frequency of use were recorded and compared between baseline and post-intervention follow-up visits.	Baseline and at 1 week, 1 month, 3 months, and 6 months post-intervention

Collaborators and Investigators

• Sponsor: Ankara City Hospital Bilkent

Publications and helpful links

General Publications

• Jadon A. Pulsed Radiofrequency (PRF) of Pericapsular Nerves Group (PENG) in Chronic Hip Pain-A Case Report. Turk J Anaesthesiol Reanim. 2021 Dec;49(6):490-493. doi: 10.5152/TJAR.2021.1080. PMID: 35110031; PMCID: PMC9472694.
• 10.5152/TJAR.2021.21230

Study record dates

Study Major Dates

• Study Start (Actual): February 1, 2026
• Primary Completion (Estimated): February 1, 2027
• Study Completion (Estimated): February 28, 2027

Study Registration Dates

• First Submitted: January 14, 2026
• First Submitted That Met QC Criteria: January 14, 2026
• First Posted (Actual): January 22, 2026

Study Record Updates

• Last Update Posted (Actual): March 18, 2026
• Last Update Submitted That Met QC Criteria: March 15, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: Pain, Chronic; Nerve Blockade; Pulsed Radiofrequency Treatment; Osteoarthritis, Hip,
• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Musculoskeletal Diseases; Arthritis; Joint Diseases; Rheumatic Diseases; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Osteoarthritis; Chronic Pain; Osteoarthritis, Hip
• Other Study ID Numbers: E2-2613941

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