Targeted Nerve Injection to the Knee (Nerve to Vastus Medialis): Comparing Two Adductor Canal Block Approaches

This randomized, double-blinded volunteer study compares two ways of performing the adductor canal (AC) nerve block at the mid-thigh to see which approach more reliably numbs the anteromedial knee. One approach is the traditional AC block placed near the saphenous nerve; the other separately targets the nerve to vastus medialis (NVM) in addition to the saphenous nerve. Healthy adult participants receive both blocks in one visit (one on each leg), with the order randomized. The primary outcome is change in quadriceps strength (a proxy for vastus medialis anesthesia) measured by load-cell dynamometry. Secondary outcomes include cutaneous sensory mapping (pinprick and cold) and the percentage of a standardized, marked knee-incision line covered by sensory block. The study uses ultrasound guidance and a standard dose of chloroprocaine, with routine monitoring to minimize risks.

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Key information

Conditions

Anesthesia, Local

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 4

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

Age ≥18 years
Able to provide written informed consent
Able and willing to comply with study procedures and ~6-hour visit
American Society of Anesthesiologists (ASA) Physical Status 1 or 2
Weight >70 kg

Exclusion criteria

BMI >35 kg/m²
Use of analgesics within 24 hours before the procedure
History of thigh trauma or surgery
Pregnant or planning pregnancy
Lower extremity deformities/tattoos interfering with block performance
Systemic neuromuscular disease
Contraindications to regional anesthesia (e.g., infection, allergy, challenging sonoanatomy)
Other health conditions that would affect safe participation

Treatment and study plan

Traditional adductor canal block

Procedure

Ultrasound-guided injection adjacent to the saphenous nerve; 20 mL of 2% chloroprocaine.

NVM (nerve to vastus medialis) targeted adductor canal block

Procedure

Ultrasound-guided injection; 10 mL 2% chloroprocaine at the NVM (confirmed by nerve stimulation), plus 10 mL at the saphenous nerve.

Chloroprocaine Injection

Drug

2% chloroprocaine

Primary outcomes

Quadriceps strength as measured by load cell dynamometer

Time frame: Day 1

Load cell dynamometers are highly accurate portable electronic devices used to measure isometric muscle strength.

Secondary outcomes

Percentage of hypothetical incision covered

Time frame: Day 1

An unblinded anesthesiologist will mark the mock total knee arthroplasty and the length of the hypothetical incision that has diminished sensation to pinprick will be determined.

Study contacts

Contact information is provided by the study sponsor or research team.

Ashley Burke

CONTACT

[email protected]

(919) 681-2849

Sponsors and collaborators

Lead sponsor

Duke University

Other

Registry information

Official study title

Study of Targeted Injection of Nerves to the Knee-A Volunteer Trial Evaluating Nerve to Vastus Medialis

Important dates

Study start: 2026
Primary completion: 2027
Study completion: 2027
First posted: Mar 3, 2026
Registry last updated: Mar 3, 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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