What is the management and detection of pseudoaneurysm (false aneurysm) following orthopedic surgery, particularly after intertrochanteric fracture fixation?

Management and Detection of Pseudoaneurysm Following Intertrochanteric Fracture Fixation

Immediate Diagnostic Approach

Obtain duplex ultrasound imaging immediately when pseudoaneurysm is suspected, as physical examination alone misses more than 60% of cases. 1, 2 The clinical presentation typically includes progressively enlarging painful thigh mass, unexplained anemia requiring transfusions, or new-onset groin/thigh pain weeks to months after surgery. 3, 4

Key Diagnostic Imaging

• Duplex ultrasound is the first-line diagnostic modality to confirm pseudoaneurysm and assess size, presence of thrombus, and arterial flow characteristics. 1, 2
• CT angiography provides definitive anatomic detail and is essential for surgical planning when endovascular or open repair is contemplated. 4
• Digital subtraction angiography serves both diagnostic and therapeutic purposes, allowing immediate coil embolization during the same procedure. 3, 5

Critical Pitfall

Do not rely on physical examination alone—clinical examination is unreliable and imaging should always be obtained when vascular injury is suspected, even with subtle symptoms. 2

Treatment Algorithm Based on Clinical Presentation

Symptomatic Pseudoaneurysms (ANY Size)

All symptomatic femoral artery pseudoaneurysms require repair regardless of size. 2 Symptomatic presentations include:

• Expanding or painful thigh mass 2
• Active bleeding or skin erosion 1, 2
• Compressive symptoms (venous thrombosis, neuropathy) 1
• Unexplained anemia requiring transfusions 2, 3

Size-Based Treatment for Asymptomatic Pseudoaneurysms

For asymptomatic pseudoaneurysms <2.0 cm: Conservative management with ultrasound re-evaluation at 1 month is reasonable, as 61% resolve spontaneously within 7-52 days. 1 However, if still present at 2-month follow-up, proceed to definitive treatment. 1

For pseudoaneurysms ≥2.0 cm: Definitive treatment is warranted due to higher rupture risk. 1, 2 Deep femoral artery pseudoaneurysms have particularly high rupture rates (33%) compared to other lower extremity pseudoaneurysms. 2

Definitive Treatment Options

First-Line: Endovascular Coil Embolization

Endovascular coil embolization is the preferred initial intervention for profunda femoris pseudoaneurysms, particularly in poor surgical candidates or when definitive orthopedic surgery is planned. 2, 3, 5 This approach achieves:

• 93% success rate for catheter-related femoral pseudoaneurysms 2
• Technical success rates of 67-100% across studies 1
• Immediate treatment during diagnostic angiography 3, 5

Alternative: Ultrasound-Guided Thrombin Injection

For accessible pseudoaneurysms, ultrasound-guided thrombin injection (100-3000 international units) achieves approximately 93% success rates. 1 However, this has limited applicability for deep profunda femoris pseudoaneurysms and carries a <2% risk of distal thromboembolism. 1

Surgical Repair Indications

Open surgical repair is necessary when: 2

• Endovascular treatment fails or is not feasible anatomically
• Infected pseudoaneurysm is present (absolute contraindication to endovascular stent grafts) 1
• Rupture into retroperitoneal space or expanding rupture into soft tissue occurs
• Definitive orthopedic reconstruction is required
• Pseudoaneurysms ≥2.0 cm persist or recur after minimally invasive treatments 1

The surgical approach typically involves ligation of the vessel proximal and distal to the pseudoaneurysm with resection. 6 No limb viability issues are expected given collateral circulation. 6

Emergency Management

Urgent surgical assessment and treatment are required for: 1

• Skin erosion or active hemorrhage (surgical emergency) 1
• Hemodynamic instability 4
• Rapidly expanding hematoma 4

Emergency evacuation of hematoma with intensive care monitoring may be necessary for massive bleeding. 4

Prevention Strategies During Surgery

To prevent this complication during intertrochanteric fracture fixation: 7

• Proper placement of retractors to avoid profunda femoris artery injury
• Use shorter drill bits or drill guards
• Ensure accurate screw length measurement
• Avoid over-penetration during drilling of distal locking holes
• Consider using shorter side-plate DHS when appropriate

Vessels Most Commonly Involved

The profunda femoris artery and its branches are involved in the vast majority of cases (approximately 80% based on the case series provided), followed by superficial femoral artery and superior gluteal artery. 3, 6, 4, 7, 5 The mechanism is typically iatrogenic injury from instrumentation (guide wires, drills, screws) or displaced bone fragments (particularly lesser trochanter). 7

Follow-Up Protocol

For conservatively managed small pseudoaneurysms, follow-up ultrasound at 1 month is mandatory, with definitive treatment if no resolution by 2 months. 1 For treated pseudoaneurysms, monitor for recurrence and ensure fracture healing proceeds appropriately. 4