History
The gamekeeper's thumb injury may be caused by a valgus stress of any kind to the thumb. The most common history is a fall onto an outstretched arm with an abducted thumb. This commonly occurs in skiers with a ski pole in the hand, which prevents adduction of the thumb when the skier falls.
Other causes of gamekeeper's thumb include the following:
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Falling onto an outstretched arm with the thumb abducted
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Valgus-producing force on the thumb MCP joint
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Generalized ligamentous laxity
Physical Examination
The contralateral, unaffected thumb should be evaluated first for ROM and valgus stability in both extension and 30° of flexion. Then, evaluate the injured thumb for swelling and pain at the ulnar aspect of the MCP joint. Ecchymosis is frequently seen.
Malik et al suggested comparison with the uninjured contralateral thumb may be unreliable in many individuals and recommended that the lack of a definite end point on stress examination to indicate a complete rupture of the ulnar collateral ligament. [7] When the investigators assessed 200 thumbs of 100 unaffected individuals in extension and 30º of flexion, 34% of subjects showed a difference of 10º or more between the contralateral thumbs in extension; another 12% of subjects showed at least a 15º difference between thumbs. When the thumbs were examined in flexion, a difference of 10º or more was noted in 22% of the thumbs, and a 15 º difference was found in 3%. [7]
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Lateral radiograph displaying a gamekeeper's fracture.
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Anteroposterior radiograph displaying a gamekeeper's fracture.
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Radiographic stress test view of the thumb, showing an ulnar collateral ligament tear.
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Ulnar collateral ligament stress test in full extension.
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Ulnar collateral ligament stress test in a flexed position to isolate the proper portion of the ligament.
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Anterior view of a hand placed in a thumb spica splint.
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Lateral view of a hand placed in a thumb spica splint.
