A skier falls with the thumb forced into abduction and hyperextension. There is tenderness over the ulnar aspect of the metacarpophalangeal joint of the thumb, laxity greater than 30 degrees on radial deviation stress testing, and a palpable mass at the thenar eminence. What is the diagnosis?

• A Bennett fracture-dislocation
• B Stener lesion complicating gamekeeper's thumb ✓
• C Rupture of the radial collateral ligament
• D de Quervain tenosynovitis

Explanation

Forced thumb abduction ruptures the ulnar collateral ligament of the MCP joint (gamekeeper's or skier's thumb). When the torn ligament retracts and comes to lie superficial to the adductor aponeurosis, it forms a palpable lump called a Stener lesion; this blocks healing and requires surgical repair. Radial collateral ligament injury follows a varus force, the opposite mechanism, and Bennett fracture would show a fracture line at the thumb metacarpal base on X-ray.

Reference: Apley and Solomon's System of Orthopaedics and Trauma, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.