Why the Thompson Approach is Preferred in Monteggia Fracture

Background: Monteggia Fracture

1. Reducing and plating the ulna fracture
2. Addressing the radial head (and often the annular ligament/proximal radioulnar joint)

The Thompson Approach (Posterior Interosseous / Dorsal Approach to the Forearm)

Why It Is Preferred — Key Reasons

1. Excellent Exposure of the Radial Head and Proximal Radius

• The Thompson approach provides direct visualization of the radiocapitellar joint, allowing:
  • Confirmation and reduction of the dislocated radial head
  • Repair or reconstruction of the annular ligament
  • Access for radial head fixation or replacement if needed

2. Safe Interval / Nerve-Sparing

• The internervous plane lies between:
  • ECRB (supplied by the radial nerve, proximal to the split)
  • EDC (supplied by the posterior interosseous nerve — PIN)
• Critically, the posterior interosseous nerve (PIN) is identified and protected throughout
• The PIN wraps around the radial neck and is at high risk in Monteggia injuries (both from the original injury and from surgery)
• The Thompson approach allows the surgeon to directly visualize and retract the PIN, dramatically reducing iatrogenic nerve injury

3. Simultaneous Ulna Access

• Combined with a posterior/medial ulna incision (ulna is subcutaneous), the Thompson approach can be used through the same or an adjacent incision, allowing:
  • Ulna ORIF (open reduction internal fixation)
  • Radial head reduction — in a single operative field
• This avoids the need for two entirely separate approaches

4. Avoidance of the Anterior Approach Hazards

• The anterior (Henry) approach to the proximal forearm passes near the radial artery and requires pronation/supination maneuvers close to neurovascular structures
• The posterior Thompson approach avoids the anterior neurovascular bundle
• In Monteggia fractures, where there is already significant soft tissue disruption, the Thompson approach is safer

5. Access to Annular Ligament

• The annular ligament — which is often torn in Monteggia injuries — is best visualized and repaired posterolaterally, exactly where the Thompson approach operates

Comparison: Thompson vs. Henry (Anterior) Approach

Summary

• Provides direct access to the radial head and annular ligament
• Allows identification and protection of the PIN (the nerve most at risk)
• Can be combined with posterior ulna fixation in a single operative field
• Avoids the anterior neurovascular structures (radial artery, main radial nerve trunk)