Genicular Nerve Versus Adductor Canal Block for Postoperative Analgesia

Genicular Nerve Versus Adductor Canal Block for Postoperative Analgesia in Patients Undergoing Total Knee Arthroplasty

Severe postoperative pain following total knee arthroplasty (TKA ) has been shown to negatively affect early mobilization, physical rehabilitation, time to discharge, and overall post-operative recovery.Therefore, reducing postoperative pain and early mobilization has become critical in reducing early mortality, preventing future chronic pain, and limiting the use of opioids The adductor canal block (ACB) has been found to be an excellent alternative to the FNB, providing adequate analgesia to the anterior knee compartment while enabling an improved postoperative range of motion by sparing motor branches to the quadriceps muscles . However, patients do not achieve adequate posterior knee analgesia as ACB pain relief is primarily limited to the anterior capsule of the knee.

Genicular nerve block (GNB) and radiofrequency ablation of genicular nerves (RFGN) were originally introduced by Choi et al. as a therapeutic alternative for chronic knee OA and were quickly adopted for use in patients undergoing TKA due to the significant pain reduction and functional improvement observed in these patients . GNBs target five main innervating branches of the knee, including the superomedial, inferomedial, superolateral, inferolateral genicular nerves, and the infrapatellar branch of the saphenous nerve.

Study Overview

• Status: Active, not recruiting
• Conditions: Postoperative Pain After Total Knee Arthroplasty
• Intervention / Treatment: Other: Spinal Anesthesia with Bupivacaine and Fentanyl; Other: Genicular nerve block with bupivacaine; Other: Adductor Canal Block (ACB) Only

Detailed Description

Chronic knee osteoarthritis (OA), an epidemic among aging populations, is a leading source of chronic pain in the United States and other developed countries . The rise in prevalence of knee OA is a direct result of factors including longer life expectancy and increased body mass index (BMI). It has been reported that at least 19% of American adults aged 45 years and older are affected . Severe postoperative pain following total knee arthroplasty (TKA ) has been shown to negatively affect early mobilization, physical rehabilitation, time to discharge, and overall post-op recovery

.Therefore, reducing postoperative pain and early mobilization has become critical in reducing early mortality, preventing future chronic pain, and limiting the use of opioids . Balancing pain control with patient ambulation often proves to be a challenge due to both the motor blocking effects of many proximal nerve blocks and the often inadequate analgesia associated with more superficial periarticular injections . Therefore, numerous modalities of analgesic treatment combining different methods of nerve blockade for effective postoperative analgesia and faster functional recovery have been discussed . However, the superior technique is yet to be

determined. Successful postoperative analgesia for TKA requires careful consideration of knee innervation, with an emphasis placed on branches of the femoral nerve innervating the anterior and medical aspects of the knee and branches of the sciatic nerve innervating the posterior aspects of the knee capsule . In the context of nerve blockade, femoral nerve block (FNB) has traditionally been a critical component in the multimodal management of pain in TKA patients due to the high analgesic efficacy and the minimal risks associated. However, FNB is associated with decreased quadriceps motor strength leading to limited physical therapy (PT) participation, delayed ambulation, and discharge . The adductor canal block (ACB) has been found to be an excellent alternative to the FNB, providing adequate analgesia to the anterior knee compartment while enabling an improved postoperative range of motion by sparing motor branches to the quadriceps muscles . However, patients do not achieve adequate posterior knee analgesia as ACB pain relief is primarily limited to the anterior capsule of the knee.

Genicular nerve block (GNB) and radiofrequency ablation of genicular nerves (RFGN) were originally introduced by Choi et al. as a therapeutic alternative for chronic knee OA and were quickly adopted for use in patients undergoing TKA due to the significant pain reduction and functional improvement observed in these patients . GNBs target five main innervating branches of the knee, including the superomedial, inferomedial, superolateral, inferolateral genicular nerves, and the infrapatellar branch of the saphenous nerve. Several bony landmarks surrounding these nerves aid in proper needle placement under fluoroscopic guidance . The GNB has a motor-sparing effect that is desirable for early ambulation postoperatively, better PT, and earlier discharge .

• Study Type: Interventional
• Enrollment (Estimated): 42
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Egypt
  • Alsharqia
    • Zagazig, Alsharqia, Egypt, 4115
      • Faculty of Medicine - Zagazig University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Patient acceptance.
• Sex: both; male and female.
• Age: over 65 years old.
• American society of anesthesiologists (ASA): II .
• Body mass index (BMI) less than 35 kg/m2.
• Operation : elective unilateral TKA.
• Duration of surgery : 2-3 hours.

Exclusion Criteria:

• History of allergy to local anesthetics (lidocaine or bupivicaine).
• Coexisting hematologic disorders or malnourished patient.
• Pre-existing major organ dysfunction including hepatic or renal failure, and left ventricular ejection fraction <30%
• Peripheral neuropathy.
• Patients with a diagnosis of cognitive impairment or significant psychiatric illness.
• Skin infection at site of block.
• Contraindication to spinal anesthesia as coagulopathy and infection at site of injection.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: control group; Receive spinal anesthesia	Other: Spinal Anesthesia with Bupivacaine and Fentanyl; spinal anesthesia will be given (under complete aseptic conditions) at the level of L3/4 while the patient in the sitting position using a spinal needle 25 G x 3.5 inches with injection of hyperbaric bupivacaine 0.5% 3ml plus fentanyl 25 microgram .
Active Comparator: Genicular nerve block group; Receive Genicular Nerve Block	Other: Genicular nerve block with bupivacaine; For the superomedial genicular nerve, a linear transducer will be placed along the longitudinal plane of the femur to visualize vastus medialis, the distal femur, and the genicular artery. Using an in-plane technique, a 10-cm echogenic 21-gauge needle will be advanced in the cephalad to the caudad direction until the needle contacted femoral shaft, just cephalad to the genicular artery, and 5 ml of 0.25% bupivacaine will be injected to spread along the femoral periosteum. This same technique, using 5 ml of 0.25% bupivacaine, will be used in a mirror image on the lateral epicondyle to block the superolateral genicular nerve. To target the inferomedial genicular nerve, a linear transducer will be placed in the sagittal plane on the anterior medial tibia.
Active Comparator: Adductor canal block group; Receive Adductor canal block	Other: Adductor Canal Block (ACB) Only; The transducer will be placed anteromedially midway between inguinal crease and medial condyle to identify sartorius muscle. Probe will be positioned perpendicular to the femoral artery and using in-plane technique with needle directed from lateral to medial to deposit local anesthetic under sartorius and around the femoral artery. 15ml bupivacaine 0.25% will be injected

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
changes of pain assessment	visual analogue scale	time frame ( at PACU, 2 hours (h ) , 4 , 8 , 12 , 16 , 24 hours postoperatively )

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Modified Bromage scale	no motor nerveblock in the lower extremity = 0 point; the affected limb cannot lift the leg = 1 point; failure to bend the knee of the affected limb = 2 points; and failure to bend the ankle = 3points	at PACU, 3 hours and 6 hours postoperatively

Collaborators and Investigators

• Sponsor: Zagazig University
• Investigators: Principal Investigator: Soha Saad mohamed Hassouna, PHD, Faculty of Medicine - Zagazig University

Study record dates

Study Major Dates

• Study Start (Actual): October 1, 2023
• Primary Completion (Estimated): May 6, 2026
• Study Completion (Estimated): June 19, 2026

Study Registration Dates

• First Submitted: May 9, 2026
• First Submitted That Met QC Criteria: May 14, 2026
• First Posted (Actual): May 15, 2026

Study Record Updates

• Last Update Posted (Actual): May 15, 2026
• Last Update Submitted That Met QC Criteria: May 14, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: total knee arthroplasty; postoperative analgesia; Adductor canal block; genicular nerve block
• Additional Relevant MeSH Terms: Organic Chemicals; Heterocyclic Compounds, 1-Ring; Heterocyclic Compounds; Anilides; Amides; Aniline Compounds; Amines; Piperidines; Socioeconomic Factors; Population Characteristics; Anesthesia and Analgesia; Demography; Anesthesia, Conduction; Anesthesia; Family Characteristics; Marital Status; Bupivacaine; Fentanyl; Anesthesia, Spinal; Single Person
• Other Study ID Numbers: 10793-14/5-2023

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Planned after completion of the study and publications
• IPD Sharing Time Frame: Planned after completion of the study and publications
• IPD Sharing Access Criteria: Contact with principal investigator
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No