Peroneal artery injury after internal fixation of a calcaneal fracture is an uncommon clinical entity. A delayed pseudoaneurysm with an arteriovenous fistula after a peroneal artery injury is even rarer (1).

The tarsal sinus incision for the treatment of calcaneal fractures is an important cause of peroneal artery end injury, the failure of hemostasis and the ongoing bleeding may lead to the formation of a pseudoaneurysm and an arteriovenous fistula (2).

Herein, we report the case of a patient who developed a pseudoaneurysm of the peroneal artery complicated by an arteriovenous fistula after surgical treatment of a calcaneal fracture through a tarsal sinus incision. In this report, we also discuss the causes and therapeutic options of this rare entity.

Aneurysms are pathologically classified as real aneurysms, pseudoaneurysms, and dissecting aneurysms. Pseudoaneurysms are mostly caused by trauma, which can be iatrogenic or non-iatrogenic (4). When blood vessels are damaged, blood flows into the tissue spaces and forms a hematoma, which in turn develops a fibrous capsule wall and is formed into a pseudoaneurysm. Pseudoaneurysm accounts for approximately 1% of all aneurysms (5). Arteriovenous fistulas are abnormal rapid channels between arteries and veins, and can be caused by aneurysms, infections, and vascular injuries. Hence, arterial vessel injuries can lead to the formation of pseudoaneurysms and arteriovenous fistulas.

Several factors can lead to arterial injuries in orthopedic surgery, including direct puncture of the fracture block, intraoperative injury, puncture injury of the drainage tube, and improper placement of screws and other internal fixation devices. The peroneal artery is a branch of the posterior tibial artery that runs obliquely behind theupper part of the flexor hallucis longus muscle, descends between the posterior part of thefibula and the tibialis posterior muscle, and distally accompanies the sural nerve. The tarsal sinus approach is used for the management of calcaneal fractures. During the procedure, the surgical incision is extended from 1 cm below the tip of the lateral malleolus to the distal 4th metatarsal, which is not generally associated with damage to the peroneal artery. However, because the steel plate is placed at the distal end, the incision needs to be extended to the Achilles tendon, which increases the risk of peroneal artery injury. Additionally, during the operation, the surface of the calcaneus needs to be sharply separated using a surgical blade; however, it cannot be separated under direct vision, which increases the possibility of peroneal artery injury. Based on the above factors, the treatment of calcaneal fractures using a tarsal sinus incision is an important cause of peroneal artery end injury. The peroneal artery thins into an arteriole, especially at its terminal part; hence, the blood pressure at this part is not high. After injury, a thrombus forms in the blood vessel to stop bleeding through local compression (6, 7). On the first day after the operation, the patient had a massive hemorrhage from the surgical site, which was controlled using pressure bandaging. The surgical incision healed at a later time. However, the peroneal artery did not thrombose and continued to bleed, resulting in a pseudoaneurysm. This was likely caused by the patient's poor coagulation function and high blood pressure. Due to our failure to detect the pseudoaneurysm in a timely manner, it led to the formation of an arteriovenous fistula.

After an arterial wall injury, a pseudoaneurysm can develop within hours to months (6, 8). The clinical manifestations of delayed pseudoaneurysms are limb pain, swelling, and progressive anemia (6, 7, 9). Physical examination can reveal a local mass, tenderness, and pulsation under the skin. When an arteriovenous fistula is formed, local tremor can be palpated at the site, and a rough, persistent, vascular murmur can be heard on auscultation along with a positive Branham sign. Imaging examinations should be performed when a pseudoaneurysm is suspected (10, 11). DSA is the gold standard for the diagnosis of pseudoaneurysms, as it can clarify the relationship between an artery and an aneurysm, and also reveal the hemodynamic features of the pathologies, while providing the basis for making appropriate treatment plans. Currently, the commonly used treatment methods for arteriovenous fistulas are thrombin injection under ultrasound guidance, transcatheter coil embolization under DSA, catheter embolization and surgical treatment (12–14). The patient in this report was treated with transcatheter coil embolization under DSA, as it was considered that DSA is more minimally invasive. and it had satisfactory postoperative outcomes.

The findings of this case report and a brief literature review suggest that a delayed pseudoaneurysm of the peroneal artery complicated by an arteriovenous fistula after calcaneal fracture is a very rare surgical complication that can be caused by iatrogenic injury and other comorbidities such as hypertension and coagulopathies. Therefore, adequate preparations should be made preoperatively, while identifying and promptly managing the patient's comorbidities. Surgeons should also be familiar with the relevant anatomy of the foot and operate carefully to avoid damaging the peroneal artery. And we can look for less traumatic techniques, including closed reduction, external fixation, and percutaneous surgery (PS), in order to reduce complication rate (15). If a vascular injury occurs postoperatively, it should be examined and treated promptly. Using these measures, the incidence of iatrogenic pseudoaneurysms complicated by arteriovenous fistulas can be reduced, and additional injury to patients can be avoided.