Evaluation of Local Anesthetic Diffusion to the Sciatic Nerve During Adductor Canal Block (DiffuCAdd)

Evaluation of Local Anesthetic Diffusion to the Sciatic Nerve During Adductor Canal Block: an Observational Study

Adductor canal block is an effective analgesic technique for major knee surgery. However, the saphenous nerve block is not sufficient to explain this block's efficiency. It has been shown that adductor canal block can spread to the tibial and fibular nerves through the adductor hiatus. However, this diffusion's frequency has never been measured. The main objective of this study is to assess clinically the frequency of the spread of the adductor canal block to the fibular and tibial nerves.

Study Overview

• Status: Recruiting
• Conditions: Sciatic Nerve; Adductor Canal Syndrome

Detailed Description

Adductor canal block is an effective analgesic technique for major knee surgery. The PROSPECT group recommends this block in first intention for locoregional anesthesia in total knee arthroplasty. It has been shown to not be inferior to femoral nerve block in this indication.

The adductor canal block targets the saphenous nerve and, through its spread in the adductor canal, the posterior branch of obturator nerve and the vastus medialis nerve. However, these nerves can't fully explain this block's efficiency.

It has been shown that local anesthetic can spread in the adductor canal to the tibial and fibular nerves through the adductor hiatus. However, this spread is inconstant, and no study has evaluated the frequency of this spread yet.

The main objective of this study is to assess the diffusion's frequency of adductor canal block to fibular and tibial nerves through clinical sensorimotor testing.

• Study Type: Observational
• Enrollment (Estimated): 70

Contacts and Locations

• Study Contact: Name: Romuald Henry, MD; Phone Number: + 33 06 72 83 17 51; Email: romuald.henry@aphp.fr

Study Locations

• France
  • Boulogne-Billancourt, France, 92100
    • Recruiting
    • Department of Anesthésia, CHU Raymond Poincaré - APHP

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Non-Probability Sample

Study Population

The study population will be all the consecutive patients scheduled for elective knee surgery under general anesthesia in our center and receiving an adductor canal block.

Description

Inclusion Criteria:

• patients over 18 years old scheduled for elective knee surgery under general anesthesia
• in our center
• receiving an adductor canal block

Exclusion Criteria:

• patients cognitively impaired,
• patients suffering from peripheral neuropathy at the lower limb,
• patients receiving an IPACK block or surgical knee infiltration to complete the adductor canal block analgesia.
• patients who refused to take part in this study
• pregnant or breastfeeding patients
• patients under guardianship
• imprisoned patients,
• patients without any medical insurance

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Frequency of local anesthetic's spread to tibial and fibular nerve	The primary outcome is the frequency of local anesthetic's spread to tibial and fibular nerve during an adductor canal block, assessed by sensory and motor testing of these nerve territories. Sensorimotor testing will be performed at four hours with loco-regional anaesthesia.	at 4 hours

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Frequency of reduction of sensitivity to cold or touch or reduction in MRC score	Frequency of reduction of sensitivity to cold or touch or reduction in MRC score in fibular and tibial nerves territories assessed at one and four hours after the adductor canal block has been performed, as well as reduction of sensitivity to cold or touch in saphenous nerve territory assessed at one and four hours after nerve block.	at 1 hour and at 4 hours
Spread of the local anesthetic in the popliteal fossa	Qualitative assessment of local anaesthetic spread in the popliteal fossa on ultrasound recording (spread or no spread).	at baseline
Evaluation of the positive and negative predictive value	Evaluation of the positive and negative predictive value, sensitivity and specificity, and positive and negative likelihood ratio of ultrasound-visualised diffusion to the tibial and fibular nerves as a predictive test for clinical impairment of the sensitivity and motor function of these nerves at 1 hour or 4 hours	at baseline and 1 hour, 4 hours
Clinical alteration assessement	Clinical alteration of sensibility and motricity will be assessed before the adductor canal block is performed and then at H1 and H4. The ultrasound scan of the popliteal fossa will be performed at the same time as the local anaesthetic is administered.	at Baseline and at 1 hour and 4 hours

Collaborators and Investigators

• Sponsor: Assistance Publique - Hôpitaux de Paris
• Investigators: Principal Investigator: Romuald Henry, MD, CHU Raymond Poincaré - APHP

Study record dates

Study Major Dates

• Study Start (Actual): December 10, 2025
• Primary Completion (Estimated): December 1, 2027
• Study Completion (Estimated): December 1, 2027

Study Registration Dates

• First Submitted: November 18, 2025
• First Submitted That Met QC Criteria: December 10, 2025
• First Posted (Actual): December 24, 2025

Study Record Updates

• Last Update Posted (Actual): December 24, 2025
• Last Update Submitted That Met QC Criteria: December 10, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: Sciatic Nerve; Adductor Canal; Local anesthesia diffusion
• Other Study ID Numbers: APHP250730; 2025-A00945-44 (Registry Identifier: IDRCB)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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