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.
• 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.