What is the incidence and cause of popliteal artery pseudoaneurysm?

Popliteal Artery Pseudoaneurysm: Incidence and Etiology

Incidence

Popliteal artery pseudoaneurysms are rare vascular lesions, with traumatic pseudoaneurysms occurring in approximately 3-4% of patients following blunt trauma. 1

• In civilian settings, a comprehensive literature review identified only 70 reported cases of popliteal artery pseudoaneurysms, underscoring their rarity 2
• Catheter-related femoral pseudoaneurysms occur after 0.1-0.2% of diagnostic angiograms and 3.5-5.5% of interventional procedures, though popliteal location is far less common than femoral 1
• The true incidence may be underestimated due to delayed presentation patterns, with diagnosis occurring weeks to years after the initial injury 2, 3

Causes

Trauma (Primary Etiology - 62.5% of Cases)

Penetrating and blunt trauma represent the main causative factors, accounting for 62.5% of all popliteal artery pseudoaneurysms. 2

Blunt Trauma

• Motor vehicle accidents, falls, and sports injuries causing deceleration or torsional forces on the popliteal artery 1
• Posterior knee dislocations with associated vascular injury 2, 3
• Delayed presentation is characteristic, with diagnosis occurring 15 days to 14 months post-injury (median 75 days) 4
• Critical pitfall: Patients often have palpable distal pulses and no obvious clinical signs of arterial injury at initial presentation, leading to missed diagnoses 3

Penetrating Trauma

• Gunshot wounds to the popliteal region 4
• Stab wounds and other penetrating injuries 2

Iatrogenic Causes (Increasing Proportion - 37.5% of Cases)

Iatrogenic trauma accounts for an increasing number of popliteal pseudoaneurysms, representing 37.5% of reported cases. 2

• Total knee arthroplasty and revision procedures are the most common iatrogenic cause, with injury occurring from posterior retractors, oscillating saws, or direct surgical trauma 5
• Arthroscopic knee procedures 2
• Catheter-based interventions involving popliteal artery access 1
• Orthopedic fixation procedures for tibial or femoral fractures 6

Other Causes

• Popliteal artery entrapment syndrome can lead to pseudoaneurysm formation through chronic compression and arterial wall damage 7
• Perigenicular neoplasia causing arterial erosion 3
• Previous vascular reconstructions with anastomotic disruption 1

Key Clinical Considerations

Diagnostic Challenges

• Delayed presentation over 2 years after blunt trauma is common, with patients presenting with painful pulsatile masses in the popliteal fossa and normal peripheral pulses 2
• Physical examination alone misses more than 60% of cases, making imaging mandatory when vascular injury is suspected 6
• Duplex ultrasound is the most rapid confirmatory test, with magnetic resonance angiography and CT angiography providing additional anatomic detail 2, 3

Associated Pathology

• Approximately 50% of popliteal aneurysms (including pseudoaneurysms) are bilateral, requiring contralateral screening 8, 9
• 50% are associated with abdominal aortic aneurysms, necessitating comprehensive vascular imaging 9

Complications Without Treatment

Untreated popliteal pseudoaneurysms carry high risks of rupture and thromboembolic episodes, leading to limb dysfunction and amputation. 2

• Deep femoral artery pseudoaneurysms have rupture rates of 33%, and similar risks apply to popliteal pseudoaneurysms 6
• Thromboembolism can destroy distal runoff vessels, with 19% of symptomatic cases requiring amputation despite surgical repair 8