Electrophysiological studies of femoral nerve by conventional techniques is often suboptimal as it is a deep-seated nerve. HRUS guided femoral nerve stimulation may improve the yield.

A prospective study was conducted at a tertiary referral center enrolling healthy subjects of either sex, aged above 18 years. Anthropometric measurements (height, weight, waist circumference (WC) and hip circumference) were recorded. Body mass index (BMI) was calculated as per WHO and Asia pacific (Asian population), WC categories by WHO and IDF (South Asian population), waist to hip ratio (WHR) categories based on WHO guideline. All enrolled individuals underwent femoral nerve motor conduction study bilaterally by both conventional and HRUS-assisted methods. Data was analyzed using R studio software. The t-test was used for comparative analysis. This study has the approval of Institutional Ethics Committee and informed consent was taken from all the study subjects.

A total of 336 femoral nerves from 168 healthy subjects were studied. The mean age of the study population was 45.5 years. Increase in CMAP amplitude (mV) by HRUS-assisted technique was significantly higher when compared to conventional technique in all the age groups, either gender, in all the BMI categories by WHO criteria and in all other categories by Asia-Pacific criteria (except one), and in all the WC categories in either gender by WHO criteria except in females WC <88 cm (P<0.01).  The 5^th percentile of the CMAP amplitude was higher in HRUS-assisted technique than conventional methods.

HRUS assisted technique yielded higher CMAP amplitude of femoral nerve when compared to conventional technique. HRUS guided femoral conduction studies maybe a good option in clinical practice.