Type IV Popliteal Arterial Entrapment Associated With an Osteochondroma

Abstract

A 27-year-old man complaining of a several-month history of right lower extremity coolness was seen by his primary care physician. He works as a farmer and tends his fields on the farm and commonly squats for milking cows. Ten days before presentation, he developed pain in his right foot with walking along with progressively increased coolness in his right leg. On physical examination, he was found to have a cool right lower extremity and no palpable dorsalis pedis or posterior tibial arterial pulses. Doppler examination produced a faint monophasic posterior tibial signal. No sensory deficits were noted. Computed tomography showed occlusion of the anterior tibial artery along with occlusion of the peroneal and posterior tibial arteries. Increased velocities were noted on the duplex ultrasound examination with provocative maneuvers in the tibial vessels. The patient underwent angiography, which demonstrated the occlusion of the anterior tibial, posterior tibial, and peroneal arteries. Catheters were then delivered to the anterior tibial and posterior tibial to allow infusion of tissue plasminogen activator. With repeated angiography, the posterior tibial artery remained occluded, and the anterior tibial artery opened with flow into the dorsalis pedis. The posterior tibial artery remaining occluded in spite of increased dose of tissue plasminogen activator. Further imaging was performed to look for a potential cause of thrombosis. The patient underwent magnetic resonance angiography with active dorsiflexion and plantar flexion to evaluate for potential popliteal entrapment as the patient’s pulse would diminish with plantar flexion. Magnetic resonance angiography demonstrated a pedunculated osteochondroma arising from the right proximal medial tibia. This lesion had significant mass effect on the adjacent medial gastrocnemius and popliteus muscles. With the active maneuvers performed, there was no evidence of compression; however, with the patient’s history, it was suspected that certain activities would cause compartment compression secondary to the osteochondroma. With this pedunculated osteochondroma, the patient was referred to orthopedics for resection. The patient underwent operative exploration with resection of the osteochondroma and release of his popliteus muscle to open the popliteal compartment. Postoperative duplex ultrasound examination demonstrated return of normal ankle-brachial index.