In the Evans classification of intertrochanteric fractures, which pattern is considered inherently UNSTABLE and requires special consideration in implant selection?

• A Type I — undisplaced fracture along intertrochanteric line
• B Type III — comminuted fracture with posteromedial cortex disruption and subtrochanteric extension ✓
• C Type II — displaced two-part fracture with intact posteromedial cortex
• D Type IV — reverse oblique fracture with lateral cortex intact

Explanation

Evans classified intertrochanteric fractures by their stability. Types I and II (undisplaced and two-part stable) retain the posteromedial cortical buttress and can be fixed with a sliding hip screw (DHS). Type III, with posteromedial comminution and subtrochanteric extension, is the most unstable — the posteromedial buttress is lost, creating a tendency for medial collapse and varus displacement. This pattern mandates a cephalomedullary nail (e.g., PFNA, InterTAN) rather than a DHS to prevent cut-out. Type IV reverse oblique also requires a nail.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

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Written and medically reviewed by the StethoPrep medical team.