Title : Behind the knee lies a threat: A case report of popliteal artery aneurysm
Abstract:
Background: A popliteal artery aneurysm is the most common type of peripheral artery aneurysm, that can lead to limb threatening ischaemia. Early recognition is essential; however, diagnosis may be delayed when presentations mimic more common conditions.
Case Presentation: A male patient in his seventies presented with unilateral left leg swelling following a fall, against a background of recurrent multifactorial falls. The initial clinical impression favoured traumatic soft tissue injury; however, subtle discolouration of the left toes raised concern for an underlying vascular pathology. Doppler ultrasonography, initially requested to exclude deep vein thrombosis, instead demonstrated left sided acute limb ischaemia, secondary to popliteal aneurysm with thrombus.
The patient had multiple cardiovascular comorbidities, including chronic kidney disease stage 4, previous repaired aortic dissection, hypertension, and prior transient ischaemic attack, placing him at high vascular risk.
Management and Outcome: Urgent vascular intervention was undertaken, including attempted femoral bypass and popliteal aneurysm decompression. Despite surgical management, due to the extent of irreversible ischaemia, an above knee amputation became necessary.
The postoperative care was further complicated by acute kidney injury superimposed on chronic kidney disease, requiring multidisciplinary management and rehabilitation input (amputation therapy team). This is essential in the management as major limb amputation affects not only physical function but also a patient's psychological wellbeing, social participation, and overall quality of life.
Discussion: This case highlights a diagnostic challenge in which a limb-threatening vascular emergency masqueraded as a common post-traumatic presentation. The presence of unilateral leg swelling may point towards a more common diagnoses such as deep vein thrombosis or soft tissue injury, while subtle signs of distal ischaemia can be overlooked. Delayed recognition of thrombosed popliteal artery aneurysms is associated with significantly worse limb salvage outcomes.
Conclusion: Popliteal artery aneurysm should remain an important differential diagnosis in patients presenting with unilateral leg swelling, particularly when accompanied by signs of distal ischaemia. This case reinforces the importance of early recognition and urgent vascular assessment in symptomatic popliteal artery aneurysms to minimise ischaemia and limb compromise.
