Knee OsteoarthritisSTAR-GNBNCT07712419
Sonographic Thigh Adjustment Ratio and Subcutaneous Fat Thickness as Predictors of Genicular Nerve Block Response in Knee Osteoarthritis
An observational study of Knee Osteoarthritis and Chronic Knee Pain, run by Gaziosmanpasa Research and Education Hospital at 1 site in Turkey (Türkiye).
Trial summary
Knee osteoarthritis (KOA) is a leading cause of chronic pain and disability. Although genicular nerve block (GNB) is an effective treatment for many patients, treatment response varies considerably. Read more about this study
- Who is it for?
- Ages 45 years and older
- Conditions the study is for
- Knee Osteoarthritis, Chronic Knee Pain
- What is being tested?
- Ultrasound-Guided Genicular Nerve Block
- Type of treatment
- Injection or infusion, Surgery or procedure
- How many people
- 30 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 5 Aug 2026to Feb 2027
- How long will I take part?
- 3 Months
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 45 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: Adults with symptomatic bilateral Kellgren-Lawrence grade 3-4 knee osteoarthritis referred from the Department of Physical Medicine and Rehabilitation to the Pain Medicine Clinic for ultrasound-guided genicular nerve block after failure of conservative treatment. Consecutive eligible patients meeting the inclusion criteria will be enrolled prospectively.
Who may be able to join
- Age ≥45 years.
- Symptomatic bilateral knee osteoarthritis with Kellgren-Lawrence grade 3 or 4.
- Visual Analog Scale (VAS) pain score ≥4 at rest or during movement.
- Scheduled to undergo first ultrasound-guided genicular nerve block.
- No intra-articular knee injection within the previous 3 months.
- Considered unsuitable for or awaiting total knee arthroplasty.
- Ability to provide written informed consent.
Who cannot join
- Inflammatory arthritis, rheumatoid arthritis, or crystal arthropathy.
- Previous knee surgery or knee prosthesis.
- Active local or systemic infection.
- Anticoagulant therapy or bleeding disorders.
- Contraindication to corticosteroids (including uncontrolled diabetes mellitus).
- Allergy to study medications.
Show all 9Show fewer
- Neurological disorders causing neuropathic knee pain.
- Dementia or inability to complete study assessments.
- Additional interventional procedures or surgery during follow-up.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Turkey (Türkiye)1 site, 1 recruiting
- Recruiting
University of Health Sciences Gaziosmanpaşa Physical Therapy and Rehabilitation Training and Research Hospital
Istanbul, 34255
Tuğçe Yavuz Mollavelioğlu, Medical Doctor, +905056751666, tugceyavuz@hotmail.com.tr
Sinem Özoğuz, Medical Doctor, turkmen_sinem@hotmail.com
About this study
Official title: Sonographic Thigh Adjustment Ratio and Subcutaneous Fat Thickness as Predictors of Genicular Nerve Block Response in Patients With Knee Osteoarthritis Undergoing Genicular Nerve Block: A Prospective Observational Study
Knee osteoarthritis (KOA) is a leading cause of chronic pain and disability. Although genicular nerve block (GNB) is an effective treatment for many patients, treatment response varies considerably. Identifying imaging biomarkers that predict clinical response may improve patient selection and optimize treatment outcomes.
This prospective observational study aims to evaluate whether the Sonographic Thigh Adjustment Ratio (STAR), calculated as anterior quadriceps muscle thickness divided by body mass index (BMI), and subcutaneous fat thickness are associated with pain relief following genicular nerve block in patients with symptomatic knee osteoarthritis. Ultrasound measurements will be obtained before the procedure, and clinical outcomes will be assessed during follow-up. The primary objective is to determine whether sonographic muscle parameters can predict treatment response after GNB.
Read the detailed description
Knee osteoarthritis is one of the most common musculoskeletal disorders worldwide and is frequently associated with chronic pain, impaired mobility, and reduced quality of life. Genicular nerve block has become an established minimally invasive treatment for patients with persistent pain despite conservative management. However, substantial variability exists in treatment response, highlighting the need for reliable predictors of clinical success.
Recent studies have suggested that ultrasound-derived muscle measurements may provide objective information regarding muscle quality and sarcopenia. The Sonographic Thigh Adjustment Ratio (STAR), defined as anterior quadriceps muscle thickness normalized to body mass index (BMI), has been proposed as an ultrasound-based indicator of muscle mass. Nevertheless, its potential role in predicting the response to interventional pain procedures has not been investigated.
This prospective observational cohort study will enroll patients with symptomatic knee osteoarthritis who undergo ultrasound-guided genicular nerve block as part of routine clinical care. Before the procedure, ultrasound measurements of anterior quadriceps muscle thickness and subcutaneous fat thickness will be obtained. STAR will be calculated by dividing anterior quadriceps muscle thickness by BMI. Clinical outcomes will be assessed using validated pain and functional outcome measures during follow-up.
The primary objective is to evaluate whether STAR predicts treatment response after genicular nerve block. Secondary objectives include investigating the predictive value of quadriceps muscle thickness and subcutaneous fat thickness individually and exploring their relationship with pain reduction and functional improvement.
- Conditions
- Knee Osteoarthritis, Chronic Knee Pain
- Being tested
- Ultrasound-Guided Genicular Nerve Block
- Keywords
- Genicular Nerve Block, Knee Osteoarthritis, Ultrasonography, Sonographic Thigh Adjustment Ratio
- Medical subject headings
- Osteoarthritis, Knee
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Ultrasound-Guided Genicular Nerve BlockProcedure or surgery
Ultrasound-guided genicular nerve block was performed as part of routine clinical care in patients with symptomatic knee osteoarthritis. The superomedial, superolateral, and inferomedial genicular nerves were targeted using a standardized ultrasound-guided technique. A standardized injectate consisting of bupivacaine, dexamethasone, and normal saline was administered to each target nerve. The procedure was performed by an experienced pain physician using the same protocol for all participants.
| Study group | Role | What they receive |
|---|---|---|
| Patients With Knee Osteoarthritis Undergoing Genicular Nerve Block | Adults with symptomatic Kellgren-Lawrence grade 3-4 knee osteoarthritis undergoing ultrasound-guided genicular nerve block as part of routine clinical care. Participants undergo baseline ultrasonographic assessment of quadriceps muscle thickness, subcutaneous fat thickness, and calculation of the Sonographic Thigh Adjustment Ratio (STAR), followed by clinical follow-up at 1 and 3 months. Receives: Procedure: Ultrasound-Guided Genicular Nerve Block |
What is being measured
The primary outcome is the main question the study is designed to answer.
Treatment Response at 1 Month Following Genicular Nerve Block
Treatment response will be defined as a ≥50% reduction in Visual Analog Scale (VAS) pain score from baseline at 1 month after ultrasound-guided genicular nerve block. The predictive value of baseline Sonographic Thigh Adjustment Ratio (STAR) for 1-month treatment response will be evaluated.
Measured: 1 month
Secondary outcomes (4)
Responder Pattern After Genicular Nerve Block
Participants will be classified according to pain response pattern after genicular nerve block: non-response, defined as less than 50% reduction in VAS pain score at 1 month; transient response, defined as at least 50% reduction at 1 month but less than 50% reduction at 3 months; and sustained response, defined as at least 50% reduction at both 1 and 3 months. The association between baseline STAR and responder pattern will be evaluated.
Measured: 1 month, and 3 months
WOMAC Score
The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) is a self-administered questionnaire used to evaluate knee and hip osteoarthritis. The global score ranges from 0 to 96, where 0 represents the best possible outcome (no pain or functional limitations) and 96 represents the worst possible outcome (severe pain and maximal functional limitations). Higher scores indicate a worse clinical outcome.
Measured: Baseline, 1 month, and 3 months
Five Times Sit-to-Stand Test
Change in functional performance assessed using the Five Times Sit-to-Stand (5xSTS) test.
The Five Times Sit-to-Stand (5xSTS) test assesses functional lower extremity strength and transitional movements. The outcome is recorded as the total time (in seconds) required for the participant to complete five consecutive sit-to-stand cycles as quickly as possible from a standard chair. The minimum possible time is 0 seconds, and a maximum cutoff score of 30 seconds is applied for participants who are unable to complete the task. Higher scores (longer times) indicate a worse outcome (poorer functional performance and lower extremity strength).
Measured: Baseline, 1 month, and 3 months
Change in Pain Intensity
Change in Visual Analog Scale (VAS) pain score from baseline after ultrasound-guided genicular nerve block.
Pain intensity is assessed using the Visual Analog Scale (VAS). The scale consists of a horizontal line where the minimum value is 0 (representing "no pain") and the maximum value is 10 (representing "the worst possible pain"). Participants mark their current pain level on this line. Higher scores indicate a worse outcome (greater pain intensity).
Measured: Baseline, 1 month, and 3 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted17 Jul 2026
- Study start5 Aug 2026
- Primary completionFeb 2027 (estimated)
- Study completionFeb 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (3)Papers the sponsor has linked to this study.
- Other trials for Knee OsteoarthritisStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 30 participants (estimated)
- Target duration
- 3 Months
Sponsor and investigators
- Lead sponsor
- Gaziosmanpasa Research and Education Hospital
- Sponsor type
- Other government
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07712419
- Sponsor's protocol ID
- MEDIPOL-EC-845-2026
- Acronym
- STAR-GNB
- Status last verified
- Jul 2026
- First submitted
- 14 Jul 2026
- Last updated
- 20 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided: The investigators have not yet made a final decision regarding individual participant data (IPD) sharing. Data sharing will be considered after study completion in accordance with institutional policies, ethical requirements, and applicable data protection regulations.
Publications
Vilchez-Cavazos F, Gamboa Alonso AA, Simental-Mendia M, Pena-Martinez VM, Acosta-Olivo CA, Villarreal-Villarreal GA. Genicular Nerve Block for Knee Osteoarthritis: A Systematic Review and Meta-analysis of Randomized Clinical Trials. Clin J Pain. 2024 Oct 1;40(10):618-624. doi: 10.1097/AJP.0000000000001240.
PubMed 39143682Razaq S, Kara M, Ozcakar L. The Relationship Between Sarcopenic Obesity and Knee Osteoarthritis: The SARCOB Study. Eur J Rheumatol. 2023 Aug 18. doi: 10.5152/eurjrheum.. Online ahead of print.
PubMed 37594394Kara M, Kaymak B, Ata AM, Ozkal O, Kara O, Baki A, Sengul Aycicek G, Topuz S, Karahan S, Soylu AR, Cakir B, Halil M, Ozcakar L. STAR-Sonographic Thigh Adjustment Ratio: A Golden Formula for the Diagnosis of Sarcopenia. Am J Phys Med Rehabil. 2020 Oct;99(10):902-908. doi: 10.1097/PHM.0000000000001439.
PubMed 32941253
Study at a glance
From the registry record, last updated by the sponsor on 20 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Sonographic Thigh Adjustment Ratio and Subcutaneous Fat Thickness as Predictors of Genicular Nerve Block Response in Patients With Knee Osteoarthritis Undergoing Genicular Nerve Block: A Prospective Observational Study
- ClinicalTrials.gov ID
- NCT07712419
- Acronym / sponsor ID
- STAR-GNB / MEDIPOL-EC-845-2026
- Conditions
- Knee Osteoarthritis, Chronic Knee Pain
- Keywords
- Genicular Nerve Block, Knee Osteoarthritis, Ultrasonography, Sonographic Thigh Adjustment Ratio
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 30 participants (estimated)
- Lead sponsor
- Gaziosmanpasa Research and Education HospitalOther government
- Study start
- 5 Aug 2026 (actual)
- Primary completion
- Feb 2027 (estimated)
- Study completion
- Feb 2027 (estimated)
- First posted
- 17 Jul 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Knee osteoarthritis (KOA) is a leading cause of chronic pain and disability. Although genicular nerve block (GNB) is an effective treatment for many patients, treatment response varies considerably. Identifying imaging biomarkers that predict clinical response may improve patient selection and optimize treatment outcomes.
This prospective observational study aims to evaluate whether the Sonographic Thigh Adjustment Ratio (STAR), calculated as anterior quadriceps muscle thickness divided by body mass index (BMI), and subcutaneous fat thickness are associated with pain relief following genicular nerve block in patients with symptomatic knee osteoarthritis. Ultrasound measurements will be obtained before the procedure, and clinical outcomes will be assessed during follow-up. The primary objective is to determine whether sonographic muscle parameters can predict treatment response after GNB.
Detailed description
Knee osteoarthritis is one of the most common musculoskeletal disorders worldwide and is frequently associated with chronic pain, impaired mobility, and reduced quality of life. Genicular nerve block has become an established minimally invasive treatment for patients with persistent pain despite conservative management. However, substantial variability exists in treatment response, highlighting the need for reliable predictors of clinical success.
Recent studies have suggested that ultrasound-derived muscle measurements may provide objective information regarding muscle quality and sarcopenia. The Sonographic Thigh Adjustment Ratio (STAR), defined as anterior quadriceps muscle thickness normalized to body mass index (BMI), has been proposed as an ultrasound-based indicator of muscle mass. Nevertheless, its potential role in predicting the response to interventional pain procedures has not been investigated.
This prospective observational cohort study will enroll patients with symptomatic knee osteoarthritis who undergo ultrasound-guided genicular nerve block as part of routine clinical care. Before the procedure, ultrasound measurements of anterior quadriceps muscle thickness and subcutaneous fat thickness will be obtained. STAR will be calculated by dividing anterior quadriceps muscle thickness by BMI. Clinical outcomes will be assessed using validated pain and functional outcome measures during follow-up.
The primary objective is to evaluate whether STAR predicts treatment response after genicular nerve block. Secondary objectives include investigating the predictive value of quadriceps muscle thickness and subcutaneous fat thickness individually and exploring their relationship with pain reduction and functional improvement.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Target follow-up
- 3 Months
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Patients With Knee Osteoarthritis Undergoing Genicular Nerve Block | – | Procedure: Ultrasound-Guided Genicular Nerve BlockAdults with symptomatic Kellgren-Lawrence grade 3-4 knee osteoarthritis undergoing ultrasound-guided genicular nerve block as part of routine clinical care. Participants undergo baseline ultrasonographic assessment of quadriceps muscle thickness, subcutaneous fat thickness, and calculation of the Sonographic Thigh Adjustment Ratio (STAR), followed by clinical follow-up at 1 and 3 months. |
Who may qualify
- Ages
- 45 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- Adults with symptomatic bilateral Kellgren-Lawrence grade 3-4 knee osteoarthritis referred from the Department of Physical Medicine and Rehabilitation to the Pain Medicine Clinic for ultrasound-guided genicular nerve block after failure of conservative treatment. Consecutive eligible patients meeting the inclusion criteria will be enrolled prospectively.
Key inclusion criteria (7 listed)
- Age ≥45 years.
- Symptomatic bilateral knee osteoarthritis with Kellgren-Lawrence grade 3 or 4.
- Visual Analog Scale (VAS) pain score ≥4 at rest or during movement.
- Scheduled to undergo first ultrasound-guided genicular nerve block.
- No intra-articular knee injection within the previous 3 months.
Key exclusion criteria (9 listed)
- Inflammatory arthritis, rheumatoid arthritis, or crystal arthropathy.
- Previous knee surgery or knee prosthesis.
- Active local or systemic infection.
- Anticoagulant therapy or bleeding disorders.
- Contraindication to corticosteroids (including uncontrolled diabetes mellitus).
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Ultrasound-Guided Genicular Nerve BlockUltrasound-guided genicular nerve block was performed as part of routine clinical care in patients with symptomatic knee osteoarthritis. The superomedial, superolateral, and inferomedial genicular nerves were targeted using a standardized ultrasound-guided technique. A standardized injectate consisting of bupivacaine, dexamethasone, and normal saline was administered to each target nerve. The procedure was performed by an experienced pain physician using the same protocol for all participants. | Procedure or surgery | Patients With Knee Osteoarthritis Undergoing Genicular Nerve Block |
Primary outcome
Treatment Response at 1 Month Following Genicular Nerve Block
Time frame: 1 month
Treatment response will be defined as a ≥50% reduction in Visual Analog Scale (VAS) pain score from baseline at 1 month after ultrasound-guided genicular nerve block. The predictive value of baseline Sonographic Thigh Adjustment Ratio (STAR) for 1-month treatment response will be evaluated.
4 secondary outcomes
Responder Pattern After Genicular Nerve Block
Time frame: 1 month, and 3 months
WOMAC Score
Time frame: Baseline, 1 month, and 3 months
Five Times Sit-to-Stand Test
Time frame: Baseline, 1 month, and 3 months
Change in Pain Intensity
Time frame: Baseline, 1 month, and 3 months
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 20 Oct 2026.
- Results publication: PubMed 39143682Vilchez-Cavazos F, Gamboa Alonso AA, Simental-Mendia M, Pena-Martinez VM, Acosta-Olivo CA, Villarreal-Villarreal GA. Genicular Nerve Block for Knee Osteoarthritis: A Systematic Review and Meta-analysis of Randomized Clinical Trials. Clin J Pain. 2024 Oct 1;40(10):618-624. doi: 10.1097/AJP.0000000000001240.
- Results publication: PubMed 37594394Razaq S, Kara M, Ozcakar L. The Relationship Between Sarcopenic Obesity and Knee Osteoarthritis: The SARCOB Study. Eur J Rheumatol. 2023 Aug 18. doi: 10.5152/eurjrheum.. Online ahead of print.
- Results publication: PubMed 32941253Kara M, Kaymak B, Ata AM, Ozkal O, Kara O, Baki A, Sengul Aycicek G, Topuz S, Karahan S, Soylu AR, Cakir B, Halil M, Ozcakar L. STAR-Sonographic Thigh Adjustment Ratio: A Golden Formula for the Diagnosis of Sarcopenia. Am J Phys Med Rehabil. 2020 Oct;99(10):902-908. doi: 10.1097/PHM.0000000000001439.
- Individual participant dataSharing planned: Undecided. The investigators have not yet made a final decision regarding individual participant data (IPD) sharing. Data sharing will be considered after study completion in accordance with institutional policies, ethical requirements, and applicable data protection regulations.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
University of Health Sciences Gaziosmanpaşa Physical Therapy and Rehabilitation Training and Research Hospital
Istanbul, Turkey (Türkiye)
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Knee Osteoarthritis and Chronic Knee Pain, run by Gaziosmanpasa Research and Education Hospital at 1 site in Turkey (Türkiye).
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 20 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Turkey (Türkiye). Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Each site lists its own contact: choose the nearest one under Trial locations. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Treatment Response at 1 Month Following Genicular Nerve Block (time frame: 1 month). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07712419, which also lists 3 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 20 Oct 2026; AzTrials last refreshed its copy on 26 Oct 2026.