[Popliteal Artery Entrapment Syndrome: Three Unusual Cases with Different Courses to Diagnosis]

Popliteal artery entrapment syndrome (PAES) is a pathology characterised by anatomical anomalies of the relative position of the popliteal artery (PA) to the medial head of the gastrocnemius muscle (MHGM), resulting in mechanical compression causing damage to and occlusion of the artery.

From 2012 to 2018, we operated on 3 male patients aged 17 to 48 years, who presented with PAES in our department. The first and oldest patient had previously undergone femoro-popliteal bypass surgery in 2003 when aged 23, with the underlying diagnosis of "posttraumatic PAOD II b" followed by several reoperations. In 2012, during the preparation of the popliteal fossa for the interposition of the aneurysmatic bypass vein a strong tendinous strand of the MHGM was found intraoperatively to be constricting the vessels. This aberrant part of the MHGM was resected and the vein replaced. The second patient was referred to us in 2014 with the diagnosis "PAOD II b with thrombosed popliteal aneurysm" after having undergone intra-arterial lysis at age 33. Due to the remaining wall adherent thrombi and position of the aneurysm, interposition of the PA with a venous graft was planned. Intraoperatively a tendon was found proximal to the aneurysm, causing significant stenosis of the PA. This structure was resected and the interposition performed as planned. The third patient was a 17 year old adolescent, who presented with plantar and calf claudication in his right leg with paleness and pulselessness. Imaging showed occlusion of the popliteal artery in both legs. After initial intra-arterial lysis, HRMRI of the knee showed the atypical course of the PA undercrossing the MHGM from the medial side. Open surgical treatment was performed by myotomy, leading to refixation of the tendon of the MHGM in its physiological position. All patients received individual medical treatment for prophylaxis of rethrombosis. All three patients declined surgical treatment of the asymptomatic contralaterally diagnosed PAES.

Popliteal artery entrapment syndrome is rare and usually associated with athletic, largely young male patients with pronounced calf muscles. Delayed diagnosis of PAES leads to severe vascular defects, unnecessary reintervention and prolonged illness as is shown in our first case. Therefore, calf and foot claudication in young patients should always bring to mind the differential diagnosis of popliteal entrapment syndrome.