What Should You Do If Vascular Injury Occurs During THA? Prevention, Recognition, and Emergency Management in Total Hip Arthroplasty

Total Hip Arthroplasty (THA) is widely recognized as one of the most successful procedures in orthopedic surgery. It has relieved pain and restored mobility for millions of patients worldwide. However, behind its excellent success rate lies a rare yet potentially catastrophic complication: vascular injury.

Although the reported incidence is only 0.2%–0.3%, once vascular damage occurs, the consequences may be devastating and even life-threatening. Injuries can range from acute external iliac vessel laceration to delayed pseudoaneurysm formation.

For orthopedic surgeons, the challenge is clear: how can we achieve ideal implant positioning while avoiding these hidden danger zones? This article summarizes the mechanisms, prevention strategies, acetabular quadrant safety principles, and emergency management of vascular injury during THA.

1. Vascular Injury in THA: Anatomy and Mechanisms

Major Vessels at Risk Around the Acetabulum

The acetabular region contains a dense vascular network, mainly derived from branches of the iliac vessels. The structures most commonly injured during THA include:

• External iliac artery and vein

• Obturator vessels

• Superior gluteal artery

• Inferior gluteal artery

• Internal pudendal vessels

Figure 1.Three-dimensional construction of pelvis and vessel structures using computed tomographic images.

Common Causes of Injury

1. Over-Reaming of the Acetabulum

Aggressive reaming may penetrate the medial wall and damage intrapelvic vessels.

2. Misplaced Acetabular Screws

Screws inserted outside safe zones may penetrate cortical bone and injure nearby vessels, especially when using cementless acetabular cups.

3. Improper Retractor Placement

Anterior retractors placed incorrectly may compress, tear, or puncture the external iliac vessels.

4. Bone Cement Complications

Extruded cement may cause:

• Thermal injury

• Vessel thrombosis

• Chronic abrasion of vessel walls

• Delayed pseudoaneurysm formation

Figure 2.Vessel injury examples.

2. The Key to Prevention: Master the Acetabular Quadrant System

What Is the Acetabular Quadrant System?

The Acetabular Quadrant System, originally described by Wasielewski, remains the gold standard for safe screw placement in THA.

Two perpendicular lines divide the acetabulum into four quadrants:

• Line A: From the anterior superior iliac spine (ASIS) to the acetabular center

• Line B: Perpendicular through the acetabular center

This creates four screw placement zones.

Figure 3.Demonstration of quadrant system used for placement of screws in total hip surgery.

1. Anterior-Superior Quadrant — Danger Zone

Structures at Risk

• External iliac artery

• External iliac vein

Clinical Advice

Avoid screw placement here. The external iliac vein is especially vulnerable because it lies more medially.

2. Anterior-Inferior Quadrant — Danger Zone

Structures at Risk

• Obturator vessels

Clinical Advice

Bone stock is often thin, and vascular penetration risk is high. This area should generally be avoided.

3. Posterior-Superior Quadrant — Safest Zone

Advantages

• Strong bone stock (often >25 mm)

• Good fixation support

Recommendation

This is usually the best and safest region for acetabular screw placement when proper screw length is selected.

4. Posterior-Inferior Quadrant — Relatively Safe Zone

Nearby Structures

• Inferior gluteal vessels

• Pudendal vessels

Recommendation

The central portion often provides acceptable bone quality and is generally considered safe with correct screw sizing.

Figure 4.Visualization of vessels surrounding the pelvis which are prone to injury from screw placement.

3. Special Situations That Require Extra Caution

High Hip Center Reconstruction

In superiorly positioned hip centers, bone stock distribution changes. Even so, posterior-superior and posterior-inferior zones are still usually safer than anterior zones.

Figure 5.Illustration of screw placement zones in the high hip center.

Crowe Type IV Developmental Dysplasia of the Hip (DDH)

In Crowe IV DDH, the acetabular center shifts anteroinferiorly.

Why This Matters

Traditional quadrant safety rules may no longer apply. Previously safe zones may become dangerously close to obturator vessels.

Best Practice

Use preoperative 3D CT angiography for precise planning.

Figure 6.Illustration of shifted quadrant system anteroinferiorly in Crowe type-IV developmental dysplasia.

Retractor and Cement Technique

Safe Retractor Placement

• Anterior retractor near the AIIS

• Inferior retractor along the anterior wall of the acetabulum

Bone Cement Control

Avoid intrapelvic extrusion and excessive volume.

4. How to Recognize and Manage Vascular Injury

Preoperative Risk Assessment

High-risk cases include:

• Revision THA

• Severe deformity

• Previous pelvic surgery

• DDH

• Intrapelvic hardware history

Recommended Imaging

• Doppler ultrasound

• CT angiography

• Vascular surgery standby when needed

Postoperative Monitoring: Beware the Delayed Killer

Vascular complications may present later and subtly.

Warning Signs

• Persistent hypotension

• Falling hemoglobin

• Swollen limb

• Neurologic deficit

• Groin pain

• Pulsatile mass

Diagnostic Tools

• Contrast CT

• Angiography

• Color Doppler ultrasound

Treatment Options

Depending on injury type:

• Open vascular repair

• Bypass grafting

• Endovascular stent placement

• Embolization

Figure 7.Photograph showing postoperative vessel injury.

5. Key Prevention Checklist for THA Surgeons

Before Surgery

• Review CT/X-ray carefully

• Identify deformity or revision risks

• Plan screw length and direction

During Surgery

• Respect quadrant safe zones

• Avoid aggressive medial reaming

• Control retractor placement

• Monitor blood loss continuously

After Surgery

• Watch vitals and hemoglobin

• Assess limb swelling and pulses

• Investigate suspicious symptoms early

Conclusion

Vascular injury during Total Hip Arthroplasty is rare, but its consequences can be catastrophic. Excellent THA surgeons do more than implant prostheses—they integrate anatomy knowledge, prevention strategy, and emergency readiness into every step of care.

From preoperative imaging planning, to safe-zone screw placement, to careful retractor and cement technique, every detail protects the patient’s life.

Remember: the best treatment for vascular injury is prevention.