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NCT Number: NCT07478783

Genicular Nerve Block Added to Femoral Nerve Block for Analgesia After Total Knee Arthroplasty

Total knee arthroplasty (TKA) is a common orthopedic procedure in which effective postoperative pain management is important for early mobilization and rehabilitation. Various regional anesthesia techniques are used as part of multimodal analgesia protocols to improve postoperative pain control. Genicular nerve block has recently been introduced as a potential motor-sparing technique that may enhance postoperative analgesia when used alone or in combination with other regional blocks.

The aim of this randomized controlled study is to evaluate whether the addition of ultrasound-guided genicular nerve block to femoral nerve block improves early postoperative analgesia in patients undergoing primary unilateral total knee arthroplasty under combined spinal-epidural anesthesia.

A total of 80 patients aged 18-80 years scheduled for elective primary unilateral TKA will be included and randomly assigned to two groups using sealed envelopes. One group will receive femoral nerve block alone (Group F), while the other group will receive femoral nerve block combined with genicular nerve block (Group FG). Postoperative pain scores using the visual analog scale (VAS), epidural patient-controlled analgesia consumption during the first 24 hours, and the time to additional analgesic requirement will be recorded and compared between the groups.

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Key information

Conditions

Total Knee Anthroplasty

Age range

18 year–80 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Ankara Bilkent City Hospital, Etimesgut, Ankara, Turkey (Türkiye)

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About this study

The aim of this prospective, randomized controlled study is to evaluate whether the addition of an ultrasound-guided (USG) genicular nerve block (GNB) to a standard femoral nerve block (FNB) improves postoperative analgesia compared with FNB alone in patients undergoing primary unilateral total knee arthroplasty (TKA).

All patients will undergo surgery under combined spinal-epidural anesthesia. After administration of the spinal block and placement of the epidural catheter, participants will be randomly assigned to one of two groups.

Group F (Control): Participants will receive an ultrasound-guided femoral nerve block using 20 mL of 0.25% bupivacaine.

Group FG (Intervention): Participants will receive an ultrasound-guided femoral nerve block (20 mL of 0.25% bupivacaine) combined with a four-point ultrasound-guided genicular nerve block targeting the superomedial, superolateral, inferomedial, and inferolateral genicular nerve branches. Each branch will receive 5 mL of 0.25% bupivacaine.

Postoperative analgesia will be standardized in both groups using an epidural patient-controlled analgesia (PCA) device operating in bolus-only mode (5 mL bolus, 20-minute lockout interval) containing fentanyl (3 µg/mL) and bupivacaine (0.5 mg/mL).

The primary outcome measure will be the total volume of epidural analgesic solution consumed during the first 24 hours after surgery. Secondary outcome measures will include postoperative pain intensity assessed using the Visual Analog Scale (VAS) at predefined time points (0, 2, 8, 12, and 24 hours), time to first additional analgesic requirement, and the incidence of postoperative side effects such as nausea or dizziness.

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

Patients aged ≥18 years

Scheduled for elective total knee replacement surgery

American Society of Anesthesiologists (ASA) physical status I-III

Planned to receive femoral nerve block with or without genicular nerve block

Ability to provide written informed consent

Exclusion criteria

Refusal to participate

Contraindication to regional anesthesia

Coagulopathy or ongoing anticoagulant therapy incompatible with nerve block

Infection at the injection site

Known allergy to local anesthetics

Severe hepatic or renal insufficiency

Cognitive impairment preventing pain assessment

Chronic opioid use or opioid dependency

Treatment and study plan

ultrasound-guided femoral nerve block

Procedure

Administration of 20 ml of 0.25% bupivacaine to the femoral nerve under ultrasound guidance. This procedure was performed on patients in both Group F and Group FG

ltrasound-guided Genicular Nerve Block

Procedure

Administration of 5 ml of 0.25% bupivacaine to each of the four genicular nerve branches (superomedial, superolateral, inferomedial, and inferolateral) under ultrasound guidance. This procedure was performed only on patients in Group FG

Primary outcomes

  1. Title: 24-hour postoperative epidural analgesic consumption.Description: The total dose (in ml) of epidural analgesic consumed by the patient via the patient-controlled analgesia (PCA) device within the first 24 hours following total knee arthroplasty su

    Time frame: First 24 hours following the total knee arthroplasty (TKA) procedure

    Total volume (in ml) of the epidural analgesic solution (fentanyl and bupivacaine) consumed by the patient via the patient-controlled analgesia (PCA) device within the first 24 hours post-surgery.

  2. 24-hour postoperative epidural analgesic consumption.

    Time frame: First 24 hours following the total knee arthroplasty (TKA) procedure.

    Total volume (in ml) of epidural analgesic solution (fentanyl and bupivacaine) consumed by the patient via the patient-controlled analgesia (PCA) device within the first 24 hours post-surgery

Sponsors and collaborators

Lead sponsor

Ankara City Hospital Bilkent

Other

Registry information

Official study title

Addition Of Genicular Nerve Block To Femoral Nerve Block Improves Early Postoperative Analgesia After Total Knee Replacement: A Randomized Controlled Trial

Acronym: GNB-FNB

Important dates

Study start
2021
Primary completion
2021
Study completion
2022
First posted
Mar 18, 2026
Registry last updated
Mar 25, 2026

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

View the official ClinicalTrials.gov record (opens in a new tab)

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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