A 54-Year-Old Man Who Developed a Femoral Pathologic Fracture from a Giant Popliteal Artery Pseudoaneurysm 7 Years After Ligation and Bypass of a Popliteal Artery Aneurysm: A Case Report and Literature Review

Abstract

BACKGROUND This case report describes a giant pseudoaneurysm that grew in size during the years following surgical treatment of a popliteal artery aneurysm, eventually causing a femoral fracture. Bone fractures secondary to vascular injuries are rarely described in the literature. CASE REPORT A 54-year-old man underwent surgical ligation and bypass for left popliteal artery aneurysm. Seven years later, he suffered a left distal femur pathologic fracture surrounded by a giant soft-tissue mass. The patient came to us with a diagnostic hypothesis of angiosarcoma from another hospital at imaging evaluation. After computed tomography angiography (CTA) and angio-magnetic resonance imaging (MRI), we made a diagnosis of femoral pathologic fracture caused by a giant pseudoaneurysm of a treated popliteal artery aneurysm refilled by an aberrant anterior tibial artery (IIA2, Kim classification). We performed excision of the mass and open reduction and internal fixation, with anatomic plate, of the fracture. Fracture healing and good functional outcome were observed at follow-up. CONCLUSIONS A possible complication of surgical treatment of popliteal artery aneurysms is refilling of the excluded aneurysm due to collateral blood flow or, such as in the present case, aberrant vessels. Therefore, the knowledge of anatomical variants of the vessels is important in surgery. Follow-up evaluation after surgery is advisable and a growing mass should be further investigated with an angio-CT scan. In case of a non-pulsating soft-tissue mass causing pathologic bone fracture, a biopsy is mandatory to exclude malignancy.

Figure 1.

Preoperative X-ray of the distal femur: pathologic fracture (AO 33A2.2). Cortical bone scalloping is evident. (A) Antero posterior view; (B) Lateral view.

Figure 2.

Preoperative clinical image. The giant soft-tissue mass (92 cm maximum circumference) is visible with the lower limb completely extra-rotated. Ulceration is visible on the antero-medial side of the thigh.

Figure 3.

Axial computed tomography (CT) scan showing the soft-tissue mass almost circumferentially surrounding the fractured bone and extending into the anterior, posterior, and medial compartments.

Figure 4.

(A) T1-weighted magnetic resonance imaging (MRI) on axial plane showing the mass with an isointense aspect to the muscle, visible at the ipsilateral limb with a hyperintense ring. (B) T2-weighted MRI image on axial plane showing greater structural inhomogeneity.

Figure 5.

(A) 3D volume-rendering CT scan of the left tight, showing: (1) Giant pseudoaneurysm (green color). (2) Great saphenous vein bypass graft (GSV bypass). (3) Popliteal artery aneurysm (PAA). (4) Anterior tibial artery (ATA). (B) Sagittal CT scan view showing: (1) Giant pseudoaneurysm. (2) Popliteal artery aneurysm (PAA). (3) Anterior tibial artery (ATA).

Figure 6.

Descriptive and schematic drawing of the refueling mechanism of popliteal aneurism by ATA. (Drawn by Dr. Melani and used with permission). (1) Anterior tibial artery arising above the joint line, taking a medial path anterior to the popliteal muscle (Type 2A-2 of Kim Classification). (2) Pseudoaneurysm. (3) Legated popliteal aneurysm. (4) Femoro-popliteal bypass. (5) Popliteal muscle. (6) Foot/ankle circulation. (7) Retrograde blood flow reperfusion of the ligated aneurysm trough the anterior tibial artery.

Figure 7.

Intraoperative image, showing the organized hematoma removed from the pseudoaneurysm (3.6 kg) on a Mayo table.

Figure 8.

Radiographic control at 1 year, demonstrating complete fracture healing and remodeling. (A) Antero posterior (AP) distal view; (B) AP proximal view; (C) Lateral view.