What is the name of the test where a patient lies down with their knee at a 45-degree angle and plantar flexion produces conus?

Pedal Plantarflexion ABI Test

The test you are describing is the pedal plantarflexion ankle-brachial index (ABI) test, where the patient lies supine with the knee flexed at approximately 45 degrees and performs active plantar flexion to provoke arterial compression or occlusion. 1

Test Positioning and Technique

• The patient is positioned supine with the knee flexed at approximately 45 degrees 1
• Active plantar flexion is performed to provoke arterial compression or occlusion, causing compression of the popliteal artery by abnormal musculotendinous structures 1
• This maneuver produces symptoms or demonstrable vascular changes that can be detected through various imaging modalities 1

Primary Clinical Applications

Popliteal Artery Entrapment Syndrome (PAES)

• The pedal plantarflexion test is specifically designed to identify dynamic arterial deviation and/or occlusion during active plantar flexion in patients with suspected PAES 1
• Real-time ultrasound duplex Doppler during plantar flexion allows visualization of flow dynamics and vessel caliber changes, making it the paramount diagnostic tool for PAES 1
• MR angiography can evaluate vascular abnormalities and dynamic changes in the popliteal artery during plantar flexion, though patients may struggle to maintain steady forced plantar flexion throughout lengthy MR sequences 1
• CT angiography with dynamic imaging can obtain images of both lower extremities at rest and plantar flexion in a single examination requiring only one contrast bolus 2

Peripheral Arterial Disease (PAD)

• The pedal plantarflexion ABI test serves as a reasonable alternative to treadmill exercise testing when a treadmill is not available, as results correlate well with treadmill ABIs 1
• This test is performed in patients with exertional non-joint-related leg symptoms and normal or borderline resting ABI (>0.90 and ≤1.40) to evaluate for PAD 1

Diagnostic Confirmation

• Selective arteriography is regarded as the gold standard in identifying dynamic arterial deviation and/or occlusion during plantar flexion, in addition to identifying vascular occlusion/stenosis, aneurysm, and thrombosis 2
• However, ultrasound duplex Doppler is typically preferred as the initial confirmatory test because it does not require ionizing radiation 2