Teaching Case

A 21-year-old avid male handball player presents with exercise-related pain for an extended period of time in both lower legs with intermittent sensibility disturbances presenting as muscle weakness on the left and paraesthesia on the right. Clinical examination showed a significantly decreased ankle-arm index on both sides after provocative exercise.

A contrast-enhanced photon-counting computed tomography (PCCT) scan of the lower limb was conducted both at rest and during active plantar flexion of the foot. In the resting state, no significant arterial stenosis was found, and the anatomical positioning of the arteries appeared normal on both sides (Figures 1 and 3). However, during maximal plantar flexion, the P2 and P3 segments of the left popliteal artery experienced complete occlusion, and the left popliteal vein was compressed by the calf musculature. There was re-injection of contrast into the vessels at the distal P3 segment, just above the bifurcation (Figure 2). Additionally, limited stenosis was observed in the P3 segment of the right popliteal artery due to a similar compression phenomenon (Figure 4).

Background

Popliteal artery entrapment syndrome (PAES) is a rare cause of lower extremity exertional claudication resulting from the external compression of vascular structures within the popliteal fossa. This syndrome arises due to a developmental anomaly where the artery is malpositioned in relation to surrounding myofascial structures, leading to vascular obstruction. PAES predominantly affects young, athletic individuals who do not have typical atherosclerotic risk factors.

Clinical Perspective

Patients with PAES often present with symptoms of unilateral or bilateral intermittent claudication in the feet and calves, triggered by exercise and relieved by rest. This clinical presentation in a young, healthy individual should prompt consideration of PAES and further diagnostic evaluation. Early recognition and treatment are essential to prevent severe complications such as thromboembolism and potential limb loss.

Imaging Perspective

The initial diagnostic workup for PAES includes Ankle-Brachial Index (ABI) measurements and Doppler ultrasound with provocative manoeuvres. These tests help identify any abnormal vascular responses. If PAES is suspected, more definitive imaging modalities such as CT angiography (CTA) or MR angiography (MRA) are recommended. These imaging techniques, especially when combined with provocative manoeuvres like maximal plantar flexion against resistance, have high sensitivity and specificity for confirming the diagnosis. Dynamic imaging helps visualise the compression and occlusion of the popliteal artery and vein, as well as any resultant vascular changes.

Outcome

Once diagnosed, the management of PAES may involve catheter-directed thrombolysis to reduce the need for surgical thrombectomy or to manage distal emboli. However, the primary treatment is myotendinous decompression, which may include vascular repair if necessary. Surgical outcomes are generally favourable, particularly when the distal circulation is preserved, ensuring good long-term functionality of the affected limb [1].

Take Home Message

1. PAES should be considered in young, athletic patients presenting with exertional claudication, particularly in the absence of atherosclerotic risk factors.
2. Early and accurate diagnosis through ABI, Doppler ultrasound, CTA, or MRA with provocative manoeuvres is critical to prevent severe complications.
3. Myotendinous decompression, with or without vascular repair, is the definitive treatment, offering positive long-term outcomes when distal circulation is preserved.

All patient data have been completely anonymised throughout the entire manuscript and related files.