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You are seeing a 17 year old boy who fell while skateboarding and sustained an axial loading force to his right thumb. He is exquisitely tender at the base of the thumb (carpometacarpal joint), and you note swelling as well. Which of the following injuries is least likely to be encountered based on this mechanism and exam?
November 14, 2021 at 6:13 pm
A) Gamekeeper’s thumb
An axial loading force on the thumb in flexion can produce base of the thumb metacarpal fractures such as the Bennett fracture, a partially intra-articular fracture on the ulnar side, or the Rolando fracture, a completely intra-articular, often comminuted / T or Y-shaped fracture at the base of the thumb. An axial loading or hyperextension force on the adducted thumb can rarely produce a trapezium fracture. All three of these present with findings at the base of the thumb, or the carpometacarpal (CMC) joint. Gamekeeper’s thumb (aka skier’s thumb) results from forced abduction/hyperextension of metacarpophalangeal (MCP) joint, injuring the ulnar collateral ligament +/- causing an avulsion fracture of the base of the proximal phalanx. These patients have tenderness on the ulnar side of MCP joint, rather than the CMC joint.