🩺 Anatomy
- Popliteal artery aneurysm is the most common peripheral arterial aneurysm of the lower limb.
- Typically occurs in elderly men and may be bilateral in up to 50% of cases.
- Associated with abdominal aortic aneurysm (AAA) in about half of patients - always screen for AAA.
- The popliteal artery lies deep in the fossa, passing between the heads of gastrocnemius - its fixed position against bone predisposes it to mural damage from atherosclerosis.
⚕️ Aetiology
- Atherosclerosis - the dominant cause in older adults.
- Other risk factors: hypertension, smoking, and male sex.
- Less commonly: connective tissue disorders such as Marfan or Ehlers–Danlos syndromes.
- Family history and systemic aneurysmal disease increase risk.
🧠 Clinical Presentation
- Pulsatile swelling in the popliteal fossa - often asymptomatic initially.
- Can cause pain due to local pressure or thrombosis.
- Embolic phenomena or acute limb ischaemia due to mural thrombus or occlusion.
- Compression symptoms: venous congestion, neuropathy, or distal oedema.
- Rarely, rupture - causes sudden severe pain and haemorrhage (uncommon but limb-threatening).
🔍 Investigations
- Duplex ultrasound (USS): first-line for diagnosis and screening both legs.
- CT or MR angiography: detailed assessment of anatomy, size, thrombus, and runoff vessels.
- Screen for associated AAA via abdominal ultrasound.
💊 Management
- All symptomatic aneurysms (pain, thrombosis, embolisation) require urgent repair to prevent limb loss.
- Asymptomatic aneurysms >2 cm are typically repaired electively to prevent thrombosis and embolic events.
- Marked angulation (>45°) or presence of thrombus also warrants repair due to embolic risk.
- Surgical options:
- Open repair: aneurysm exclusion with bypass (vein graft gold standard).
- Endovascular repair: covered stent graft - increasingly used in high-risk or elderly patients.
- Post-repair: antiplatelet therapy and duplex surveillance for graft/stent patency.
📚 References
🩸 Teaching tip:
A popliteal aneurysm is a peripheral pulse that can cost a limb.
Always check both legs and the abdomen - where there’s one aneurysm, there’s often another.
The key danger isn’t rupture, but embolisation and thrombosis. 🚨
