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NCT Number: NCT07360093

PENG Block & PENG PRF

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.

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Key information

Age range

18 year–80 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Ankara Bilkent City Hospital

Ankara, 06680, Turkey (Türkiye)

Location status: Recruiting

Location contact

Ulku Sabuncu Assoc. Prof.

CONTACT

905337085212

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

PENG Block Pulsed radiofrequency

Procedure

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.

Primary outcomes

  1. Change in pain intensity measured by the Visual Analog Scale (VAS, 0-10; higher scores indicate worse pain)

    Time frame: baseline (pre-procedure) and at 1 week, 1 month, 3 months, and 6 months after the procedure.

    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.

Secondary outcomes

  1. Change in Pain, Stiffness, and Physical Function Measured by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC, 0-96)

    Time frame: baseline (pre-procedure) and at 1 week, 1 month, 3 months, and 6 months after the procedure.

    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.

  2. Change in Hip Function Measured by the Harris Hip Score (HHS, 0-100)

    Time frame: Baseline (pre-procedure), 1 week, 1 month (primary functional endpoint), 3 months, and 6 months after pulsed radiofrequency (PRF) treatment.

    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.

  3. Secondary Outcome: TAnalgesic Use

    Time frame: Baseline and at 1 week, 1 month, 3 months, and 6 months post-intervention

    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.

Study contacts

Contact information is provided by the study sponsor or research team.

Ulku Sabuncu MD, Assoc. prof.

CONTACT

[email protected]

+905337085212

Sponsors and collaborators

Lead sponsor

Ankara City Hospital Bilkent

Other

Registry information

Official study title

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

Acronym: PENG-PRF

Important dates

Study start
2026
Primary completion
2027
Study completion
2027
First posted
Jan 22, 2026
Registry last updated
Mar 18, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

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This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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