Popliteal artery aneurysm

Popliteal artery aneurysms are the most common peripheral arterial aneurysm and the second most common aneurysm after abdominal aortic aneurysms.

Overall these are uncommon. There is an increased incidence with age and a strong male preponderance (M:F ratio 10 to 30:1),

  • asymptomatic incidental finding
  • pulsatile mass
  • may present with complications (see below)

They are bilateral in 50 to 70% of cases. They can either be true or false aneurysms:

There is a strong association with abdominal aortic aneurysms; ~ 40% of patients with a popliteal artery aneurysm have a AAA, though only 10-15% of patients with AAA have popliteal artery aneurysms.

  • often the initial imaging modality of choice 4
  • useful for assessment of vessels distal to the aneurysm
  • poorer spatial resolution than CTA and DSA although newer techniques (e.g. contrast-enhanced equilibrium phase imaging) are showing promise 6

Angiography can directly show mural calcification and aneurysmal dilatation. In about 26% of cases, conventional angiography does not demonstrate aneurysmal dilatation due to thrombus formation within the aneurysmal sac 7. Instead, it appears as an acute bend in the course of the popliteal artery at the level of the knee joint. This secondary sign is called "dog leg" sign 5,7.

Symptomatic aneurysms are treated. Asymptomatic aneurysms >2 cm diameter also considered for elective treatment.  

  • endovascular insertion of covered stent: flexible soft device (such as Viabahn stent graft) has better outcome due to movement at the knee crease; 5 year patency rate for Viabahn stent graft is 70%; disadvantages include kinking or fracture of stent due to excessive movement
  • open surgical repair (usually aneurysmorrhaphy and bypass surgery): vein graft typically used; 5 year patency rate of vein graft is also 70%
  • distal thromboembolism (commonest: occurs in 18 to 31% of untreated cases)
  • rupture (rare)
  • pressure effects if large enough

The differential (mainly clinical due to transmitted pulsations of the popliteal artery) include:

Knee pathology

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

Share article

Article information

rID: 1909
System: Vascular
Section: Pathology
Tags: vascular, knee
Synonyms or Alternate Spellings:
  • Popliteal artery aneurysms
  • Popliteal arterial aneurysm
  • Popliteal arterial aneurysms

Support Radiopaedia and see fewer ads

Cases and figures

  • Drag
    Case 1: bilateral
    Drag here to reorder.
  • Drag
    Case 2
    Drag here to reorder.
  • Drag
    Case 2
    Drag here to reorder.
  • Drag
    T2*
    Case 3: giant aneurysm on MRI
    Drag here to reorder.
  • Drag
    Case 4
    Drag here to reorder.
  • Drag
    Case 5
    Drag here to reorder.
  • Drag
    Case 6
    Drag here to reorder.
  • Drag
    Case 7: bilateral
    Drag here to reorder.
  • Updating… Please wait.
    Loadinganimation

    Alert accept

    Error Unable to process the form. Check for errors and try again.

    Alert accept Thank you for updating your details.