This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Upper Limb Traumatology, Subject name: Orthopaedics
[{'content': 'Game keepers thumb is: \nSelect and explain. \nA. Thumb metacarpophalangeal joint ulnar collateral ligament rupture, B. Thumb metacarpophalangeal joint radial collateral ligament rupture, C. Thumb interphalangeal joint ulnar collateral ligament rupture, D. Thumb interphalangeal joint radial collateral ligament rupture', 'role': 'user'}, {'content': "Answer: A \nExplanation: GAME KEEPER'S/SKIER'S THUMB Injury to the thumb metacarpophalangeal joint ulnar collateral ligament- most common injury of 1st MCP joint. Pain, swelling and ecchymosis around the metacarpophalangeal joint. On clinical examination, a prominent lump can be palpated, which represents the ulnar collateral ligament being displaced by the adductor aponeurosis.", 'role': 'assistant'}]