Popliteal Artery Pseudoaneurysm: An Unusual Complication of Tibial Traction
Traction pins are an essential tool in the orthopedic surgeon’s armamentarium. Historically a definitive treatment for some fractures, they are mainly used as a temporizing measure today. Despite their frequent use and relative simplicity, traction pins can have complications, many of which can be subtle and easily overlooked.
Here we report on an unusual complication that was difficult to diagnose but caused significant morbidity before being diagnosed and treated. Pseudoaneurysms can cause a range of symptoms and usually present as a painful, tender, pulsatile mass, but in this instance the popliteal artery pseudoaneurysm presented as chronic, painful lower extremity swelling. With diagnosis and treatment, the patient’s symptoms resolved. We discuss the complications associated with traction-pin placement.
Traction-pin placement is a basic orthopedic skill learned in the early years of residency training. Skeletal traction historically was used as definitive treatment for long-bone fractures, and it is still in use in countries without access to modern medical care.1,2 In current orthopedic practice, proximal tibial and distal femoral traction pins are most commonly used to temporize femoral shaft and acetabular fractures, respectively, before definitive surgical intervention. Although traction-pin placement is common, there are complications that can cause morbidity ranging from skin irritation to death.
In this article, we report on a popliteal artery pseudoaneurysm, a unique complication related to pin placement. The patient provided written informed consent for print and electronic publication of this case report.
Case Report
A 22-year-old woman with no past medical history was driving a car at 35 miles per hour when she hit a telephone pole. She was wearing a seatbelt. She was taken by ambulance for a trauma evaluation. She sustained a right posterior hip dislocation with an associated Pipkin 2 femoral head fracture (Figures 1A, 1B), a right elbow skin avulsion, and a scalp abrasion.
The patient underwent closed hip reduction under sedation, and a proximal tibial traction pin was placed (Figures 2A, 2B). At our institution, proximal tibial traction pins are placed 2 cm distal and 2 cm posterior to the tibial tubercle without the use of fluoroscopy. The skin leg is prepared and draped in sterile fashion, and a local anesthetic is used to anesthetize the skin and periosteum on the medial and lateral aspects of the leg. A 1.5-cm incision is made laterally, and soft tissue is spread laterally down to the periosteum. Then the traction pin (always the largest nonthreaded pin available) is used to sound the anterior and posterior aspects of the tibia—the goal being to end at the anterior two-thirds/posterior one-third mark. After the pin is advanced through both cortices, the place where the pin will exit the skin is noted, and another incision is made. For this patient, no complications were noted at time of pin placement.
On postinjury day 1, she was taken to the operating room for open reduction and internal fixation of the femoral head fracture through a Smith-Petersen approach. At the same time, a traction pin was removed. Routine postoperative protocols were followed. The patient was started on enoxaparin, was seen by physical therapy on postoperative day 1, and was kept non-weight-bearing on the right lower extremity. Pain was well controlled, and the patient was discharged on postoperative day 3 (postinjury day 4).
Three weeks after surgery, she returned for a scheduled follow-up with complaints of paresthesia and decreased sensation in the right lateral cutaneous femoral nerve distribution and burning pain in the toes. A stiff right ankle was noted. A night splint, amitriptyline, and additional pain medications were ordered.
The patient returned for her scheduled 6-week follow-up reporting she had not taken the enoxaparin because her pharmacy “did not have any.” Her primary care physician had given her “another blood thinner,” which she had taken orally for 1 to 2 weeks. She had complaints of right calf pain, but her hip was pain-free. There was a large amount of calf swelling and tenderness along with mild equinus contracture of the ankle. She was sent to the emergency department (ED) for Doppler ultrasound evaluation for deep venous thrombosis (DVT).
Duplex Doppler imaging of the deep venous system of the lower extremities was performed with visualization from the common femoral veins to the popliteal veins bilaterally. There was normal compressibility, respiratory phasicity, and flow with no intraluminal thrombus. A radiograph of tibia and fibula showed soft-tissue swelling and lucencies from the traction pin but no other abnormalities.
Eight weeks after surgery, the patient returned to the ED because of continuing calf pain. Given that the ultrasound findings had been negative, magnetic resonance imaging (MRI) was ordered, and orthopedic follow-up scheduled. About 10 weeks after surgery, she returned to the ED, still with calf pain, and reported having been unable to go for her MRI because of financial reasons. Physical examination revealed increased calf swelling and a new ecchymosis tracking along the tibia. Repeat ultrasound, performed from the common femoral veins through the popliteal veins, showed a right posterior calf pseudoaneurysm (8.5×4.3×5.3 cm) arising from the popliteal artery about 5 cm below the popliteal fossa. In addition, a large hematoma was seen originating in the upper posterior calf and extending inferiorly (Figure 3).
Computed tomography angiogram confirmed the ultrasound diagnosis of a large (5.6×4.8-cm) right calf pseudoaneurysm arising possibly from a small muscular branch of the proximal tibioperoneal trunk, with a large surrounding hematoma in the posterior compartment of the proximal right calf (Figure 4). Vascular surgery was consulted, and coil embolization of the pseudoaneurysm was performed later that night in the interventional radiology suite.
