Femoral Triangle Block vs Adductor Canal Block on Early Quadriceps Function After Total Knee Arthroplasty

Official title

Postoperative Effects of Femoral Triangle Block Versus Adductor Canal Block on Early Quadriceps Function After Total Knee Arthroplasty Under a Multimodal Analgesia Protocol: A Randomized Double-Blind Controlled Trial

Overview

The goal of this clinical trial is to compare the effects of femoral triangle block (FTB) and adductor canal block (ACB) on early quadriceps function after total knee arthroplasty (TKA). The main question it aims to answer is whether FTB causes more early quadriceps functional impairment than ACB under a standardized multimodal analgesia protocol. Researchers will compare FTB and ACB using a composite binary functional outcome measured 6 hours after block completion. Quadriceps functional impairment is defined as the inability to perform a structured straight leg raise or quadriceps muscle strength \<50% of the preoperative baseline. Participants will be randomly assigned to receive ultrasound-guided FTB or ACB. All participants will also receive a popliteal plexus block and standardized multimodal analgesia.

Detailed description

This is a single-center, randomized, parallel-group clinical trial designed to compare the postoperative effects of femoral triangle block (FTB) and adductor canal block (ACB) on early quadriceps function after primary unilateral total knee arthroplasty (TKA). A total of 136 adult participants are planned for enrollment at Daiyukai General Hospital.

Participants will be randomly assigned to receive ultrasound-guided FTB or ultrasound-guided ACB as part of a standardized multimodal analgesia protocol. In all participants, a popliteal plexus block will also be performed to standardize posterior knee analgesia.

The primary outcome is quadriceps functional impairment at 6 hours after block completion, assessed using a composite binary functional outcome defined as the inability to perform a structured straight leg raise or normalized isometric quadriceps muscle strength \<50% of the preoperative baseline.

Secondary outcomes include quadriceps functional impairment at 24 hours after block completion using the same composite definition, postoperative pain intensity, rescue analgesic consumption, early mobilization and rehabilitation-related measures, active knee range of motion, time to achieve active knee flexion of at least 120 degrees, and ultrasound-assessed local anesthetic spread.

The study aims to determine whether FTB results in greater early motor impairment than ACB under a standardized multimodal analgesia protocol while maintaining clinically appropriate postoperative analgesia.

Interventions

• Procedure Femoral Triangle Block (FTB) Group
  Ultrasound-guided femoral triangle block performed as part of a standardized multimodal analgesia protocol for total knee arthroplasty. A total of 10 mL of 0.25% levobupivacaine is injected in the femoral triangle to achieve sensory blockade of the saphenous nerve, the nerve to vastus medialis, and surrounding structures. The injection is performed at the distal femoral triangle under ultrasound guidance, targeting the perineural space adjacent to the relevant nerve branches. In all participa
• Procedure Adductor Canal Block (ACB) Group
  Ultrasound-guided adductor canal block performed as part of a standardized multimodal analgesia protocol for total knee arthroplasty. A total of 10 mL of 0.25% levobupivacaine is administered in a divided manner within the proximal adductor canal, targeting both the saphenous nerve within the canal and the nerve to vastus medialis running adjacent to the canal. The injection is performed under ultrasound guidance to achieve selective sensory blockade while minimizing motor involvement. In all

Primary outcome measures

• Participants with quadriceps functional impairment at 6 hours after block completion [Time frame: 6 hours after block completion]

Secondary outcome measures (12)

• Participants with quadriceps functional impairment at 24 hours after block completion [Time frame: 24 hours after block completion]
• Participants able to perform a structured straight leg raise at 6 and 24 hours after block completion [Time frame: 6 and 24 hours after block completion]
• Normalized isometric quadriceps muscle strength at 6 and 24 hours after block completion [Time frame: 6 and 24 hours after block completion]
• Postoperative pain intensity at rest on the Numeric Rating Scale [Time frame: 1, 2, 3, 6, 12, 18, and 24 hours after surgery]
• Postoperative pain intensity during active knee movement on the Numeric Rating Scale [Time frame: 1, 2, 3, 6, 12, 18, and 24 hours after surgery]
• Participants requiring any rescue analgesic during the first 24 postoperative hours [Time frame: Within the first postoperative 24 hours]
• Number of rescue analgesic administrations during the first 48 postoperative hours [Time frame: Within the first postoperative 48 hours]
• Time to first mobilization [Time frame: Within 24 hours after block completion]
• Ability to stand during the first postoperative rehabilitation session [Time frame: Postoperative day 1]
• Walking distance during routine postoperative rehabilitation [Time frame: From postoperative days 1 to 7]
• Active knee flexion angle of the operated knee [Time frame: Postoperative days 1, 2, 3, and 7]
• Active knee extension deficit angle of the operated knee [Time frame: Postoperative days 1, 2, 3, and 7]

Eligibility criteria

Inclusion criteria

• Adult patients (≥ 20 years of age) are scheduled to undergo primary unilateral TKA.
• American Society of Anesthesiologists (ASA) physical status I-III.
• Ability to ambulate independently prior to surgery.
• Ability to understand the study procedures and provide written informed consent.
• Planned perioperative anesthesia management including regional anesthesia as part of standard clinical care.
• Ability to extend the knee below 30 degrees preoperatively (no knee extension contracture)

Exclusion criteria

• Known allergy or contraindication to local anesthetic agents used in this study.
• Pre-existing neurological or neuromuscular disorders affect lower limb strength or motor control.
• Severe cognitive impairment or psychiatric conditions interfere with study participation or assessment.
• History of revision knee arthroplasty on the operative side.
• Severe preoperative quadriceps weakness that precludes reliable baseline strength assessment.
• Any condition deemed by the investigator to make participation inappropriate.

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Double blind

Primary purpose

Treatment

Study locations

Japan · 1 center

• Department of Anesthesiology, Daiyukai General Hospital — Ichinomiya

Identifiers

NCT: NCT07524387 · DGH-2025-022

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗