Phenol Neurolysis Versus Local Anesthetic Plus Steroid Genicular Nerve Block in Knee Osteoarthritis

Salim Sencar

Status: Active, not recruiting

Conditions: Genicular Nerve Block; Knee Osteoarthritis

Treatments: Drug: Phenol Injection; Drug: Bupivacaine + Triamcinolone Acetonide Injection

Study type: Observational

Funder types: Other

Identifiers

NCT07267039

OMU-FTR-2025/44

OMU-EC-2025-44 (Other Identifier)

Details and patient eligibility

About

This study aims to evaluate two different ultrasound-guided procedures for patients with knee osteoarthritis (gonarthrosis) who did not benefit from conservative treatments. The first method is genicular nerve neurolysis with phenol, a chemical agent that blocks nerve signals and may reduce pain for a longer period. The second method is a genicular nerve block with local anesthetic (bupivacaine) and corticosteroid (triamcinolone acetonide), which is commonly used to relieve pain and inflammation.

A total of 42 patients are followed prospectively. Pain intensity is measured using the Visual Analog Scale (VAS), and functional outcomes are assessed with the WOMAC Index and Oxford Knee Score (OKS). Joint range of motion, need for pain medications, and possible side effects are also monitored.

The results will help to compare the effectiveness and safety of phenol neurolysis and triamcinolone acetonide-local anesthetic nerve block, and may guide future treatment choices for patients with knee osteoarthritis.

Full description

Knee osteoarthritis (gonarthrosis) is a major cause of chronic pain and disability. Patients who fail to respond to conservative treatments such as medications, physical therapy, and exercise often require interventional options for pain relief.

This prospective observational cohort study compares two ultrasound-guided procedures targeting the genicular nerves of the knee:

Genicular nerve neurolysis with phenol - phenol induces protein denaturation and Wallerian degeneration in nerve fibers, providing long-term analgesia.

Genicular nerve block with local anesthetic (bupivacaine) and corticosteroid (triamcinolone acetonide) - this combination offers immediate pain reduction from nerve blockade and potential prolonged relief due to the anti-inflammatory action of the steroid.

A total of 42 patients with Kellgren-Lawrence grade 3-4 knee osteoarthritis and moderate-to-severe pain (VAS ≥ 4 for ≥ 3 months) are prospectively followed. Interventions are performed under ultrasound guidance at the superomedial, superolateral, and inferomedial genicular nerves.

The primary outcome is change in pain severity (VAS). Secondary outcomes include functional improvement assessed by the WOMAC Index and Oxford Knee Score (OKS), joint range of motion, need for nonsteroidal anti-inflammatory drugs (NSAIDs), and procedure-related adverse events. Assessments are performed at baseline, 2 weeks, and 3 months post-procedure.

The study aims to provide comparative evidence on the effectiveness and safety of phenol neurolysis versus triamcinolone acetonide-local anesthetic block, helping to guide clinical practice in the management of knee osteoarthritis.

Enrollment: 42 estimated patients

Sex: All

Ages: 40+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Age ≥ 40 years
• Diagnosis of knee osteoarthritis (Kellgren-Lawrence grade 3-4) confirmed by radiographic evaluation
• Moderate to severe knee pain for at least 3 months (VAS ≥ 4)
• Inadequate response to conservative treatments (e.g., medications, physical therapy, exercise)
• Ability to provide informed consent

Exclusion criteria

• History of knee surgery (e.g., total knee arthroplasty) on the affected side
• Intra-articular injection (hyaluronic acid, corticosteroid, PRP, etc.) within the last 6 months
• Secondary arthritis (e.g., rheumatoid arthritis, gout, septic arthritis, trauma-related arthritis)
• Severe coagulopathy or current use of anticoagulant therapy contraindicating injection
• Local skin infection at the injection site
• Known allergy or contraindication to phenol, bupivacaine, or triamcinolone acetonide
• Severe uncontrolled systemic disease (e.g., advanced cardiac, hepatic, or renal failure)
• Pregnancy or breastfeeding

Trial design

42 participants in 2 patient groups

Phenol Neurolysis

Description:

Patients in this group receive ultrasound-guided genicular nerve neurolysis. Using a 22G, 50 mm needle under ultrasound guidance, injections are performed at the superomedial, superolateral, and inferomedial genicular nerves. At each site, 2 mL of 6% phenol is injected to achieve chemical neurolysis and long-term pain relief.

Treatment:

Drug: Phenol Injection

Local Anesthetic + Triamcinolone Acetonide Block

Description:

Patients in this group receive ultrasound-guided genicular nerve block. At the same three target nerves (superomedial, superolateral, inferomedial), 2 mL of a mixture containing 0.25% bupivacaine and 20 mg triamcinolone acetonide is injected at each site. This combination provides nerve blockade with additional anti-inflammatory effect from the corticosteroid.

Treatment:

Drug: Bupivacaine + Triamcinolone Acetonide Injection