In elbow trauma, a Monteggia fracture-dislocation is defined as a fracture of the proximal ulna with dislocation of the radial head. The Bado classification Type I, which accounts for the majority of cases, involves:

• A Anterior dislocation of the radial head with apex anterior (angulation anterior) ulnar fracture ✓
• B Posterior dislocation of the radial head with apex posterior ulnar fracture
• C Lateral dislocation of the radial head with fracture of the radial shaft in addition
• D Anterior dislocation of the radial head without ulnar fracture (equivalent lesion)

Explanation

Bado Type I (60–70% of Monteggia injuries) consists of apex-anterior (forward) angulation of the proximal ulnar fracture with anterior dislocation of the radial head. The direction of radial head dislocation always matches the direction of the apex of the ulnar fracture. Type II (apex posterior/posterior radial head dislocation) is the adult-predominant variant and carries greater risk of posterior interosseous nerve injury. Type III is lateral dislocation (paediatric). A missed Monteggia fracture leads to chronic radial head dislocation and chronic PIN palsy.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.