Popliteal artery entrapment syndrome

Dr Andrew Dixon et al.

Popliteal artery entrapment syndrome (PAES) refers to symptomatic compression or occlusion of the popliteal artery due to a developmentally abnormal relationship with the medial head of gastrocnemius (MHG) or less commonly with popliteus or fibrous bands. 

Epidemiology

The anatomic anomalies may be seen in up to 3% of the population and are often bilateral 2 (~2/3 of cases). Most individuals; however, are asymptomatic, and the true clinical syndrome is far less common. Individuals with well-developed muscles are more likely to be symptomatic, which probably explains why the syndrome is most often found in young sports persons (~60 % in those <30 years) with a male to female ratio of 15:1 3.

Clinical presentation

Symptoms are typically those of intermittent claudication. Physical examination can reveal signs of arterial compromise, particularly when the ankle is plantarflexed. Chronic repeated arterial compression can lead to acute thrombus formation and presentation with acute limb-threatening ischaemia in those with poorly developed collateral vessels.

Pathology

Arterial compression can result in chronic vascular microtrauma, local premature arteriosclerosis, and thrombus formation. This can result in distal ischaemia. Stenosis and turbulent flow may lead to post-stenotic ectasia or aneurysm formation.

Five anatomic types of entrapment are typically described 1:

  • type I: popliteal artery has an aberrant medial course around MHG (see case 1)
  • type II: artery is not displaced but the MHG inserts more lateral than usual ;  the artery passes medial and beneath the muscle
  • type III: an accessory slip of MHG slings around the artery
  • type IV: artery lies deep in popliteal fossa entrapped by popliteus or fibrous band
  • type V: both popliteal artery and vein are entrapped

Radiographic features

Ultrasound

May show arterial compression elicited by manoeuvres such as plantar flexion and dorsiflexion 5. Doppler may demonstrate an increase in peak velocity 8.

MRI

MRI is the best imaging modality to demonstrate the underlying anatomic type of entrapment, which helps guide surgical management 4. A medial slip of the medial head of the gastrocnemius may be seen, compressing the popliteal artery.

Angiography/DSA

Lower limb angiography usually demonstrates medial deviation/compression of the popliteal artery when the ankle is plantarflexed. Occlusion of the vessels with thrombus can be seen in the acute presentation. Usually, collateral vessels are present. Even slight irregularity of the vessel can indicate a degree of entrapment 2

Treatment and prognosis

Acute limb-threatening thrombosis requires urgent bypass surgery. Intermittent occlusion can usually be cured with the release of the popliteal artery alone or with saphenous vein bypass 2.     

Differential diagnosis

Imaging differential considerations include

See also 


Knee pathology

The knee is a complex synovial joint that can be affected by a range of pathologies:

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Article Information

rID: 9410
Section: Syndromes
Synonyms or Alternate Spellings:
  • PAES
  • Popliteal artery entrapment syndrome (PAES)
  • Drag
    Popliteal Artery ...
    Case 1: MRA
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    Popliteal Artery ...
    Case 1: axial PD
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    Unsubtracted angi...
    Case 2: angiogram during plantar flexion
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