Gamekeeper thumb is essentially synonymous with skier thumb, although the latter has a more acute injury connotation. It is an avulsion or rupture of the ulnar collateral ligament (UCL) of the thumb.
The repetitive breaking-of-necks of small game (rabbits and such) resulted in chronic injury to the ulnar collateral ligament of the metacarpophalangeal joint of the thumb with weakening and eventual tear. Gamekeeping and poaching have largely fallen by the wayside as a recreational activity. This injury is now seen more frequently in skiers, and in the 80s, break dancers.
Typically (in skiers) the stock and stock-strap forcibly abducting the thumb during a fall or particularly aggressive pole-plant results in acute pain. In gamekeepers, perhaps an unusually thick-necked rabbit was the cause?
The aim of imaging is to identify a fracture; determine if there is instability (joint space widening) and identify a Stener lesion. A classification into six types has been proposed by Hintermann et al in 1993 1 (see classification of gamekeeper thumb).
This is almost always the first examination and is often able to give the diagnosis. If a small avulsion fracture is present, then this will be seen at the ulnar corner of the base of the proximal phalanx.
If the tear is in the midsubstance, with no associated fracture then the ulnar side of the joint may appear widened. If the diagnosis is suspected stress views were once upon a time recommended, however concern now exists that performing these views can displace the torn undisplaced end of the ligament dorsal to adductor pollicis muscle thereby creating a Stener lesion 3.
Ultrasound is helpful in identifying not only the tear but also whether or not a Stener lesion is present. Clearly this requires a knowledge of local anatomy and use of a high frequency probe.
MRI is increasingly used to asses x-ray occult injuries to the ulnar collateral or to attempt to identify a Stener lesion. Findings include:
- discontinuity of the ligament +/- joint capsule
- bone marrow oedema and fracture
- Stener lesion 4
Treatment and prognosis
Treatment depends on classification, but essentially boils down to whether there is displacement or instability: if there is, surgical fixation is required.
Additionally the presence of a Stener lesion (interposition of the adductor pollicis muscle and adductor aponeurosis between torn end of the ulnar collateral ligament and the base of the proximal phalanx) is an indication for surgery 3.
History and etymology
It was first described in, you guessed it, Scottish gamekeepers by Campbell in 1955 2. Clearly gamekeepers who also ski are almost certain to incur this injury.
- fractures of the thumb
Wrist and hand fractures
- wrist and hand fractures (Amsterdam wrist rules)
- distal radial fracture (Frykman classification)
- distal ulna fractures
- fracture dislocations of the radius and ulna
- carpal fractures
- metacarpal fractures
- phalangeal fractures
- 1. Hintermann B, Holzach PJ, Schütz M et-al. Skier's thumb--the significance of bony injuries. Am J Sports Med. 21 (6): 800-4. - Pubmed citation
- 2. Campbell CS. Gamekeeper's thumb. J Bone Joint Surg Br. 1955;37-B (1): 148-9. J Bone Joint Surg Br (pdf) - Pubmed citation
- 3. O'callaghan BI, Kohut G, Hoogewoud HM. Gamekeeper thumb: identification of the Stener lesion with US. Radiology. 1994;192 (2): 477-80. Radiology (abstract) - Pubmed citation
- 4. Hinke DH, Erickson SJ, Chamoy L et-al. Ulnar collateral ligament of the thumb: MR findings in cadavers, volunteers, and patients with ligamentous injury (gamekeeper's thumb). AJR Am J Roentgenol. 1994;163 (6): 1431-4. AJR Am J Roentgenol (abstract) - Pubmed citation
- 5. Hergan K, Mittler C, Oser W. Pitfalls in sonography of the Gamekeeper's thumb. Eur Radiol. 1997;7 (1): 65-9. doi:10.1007/s003300050111 - Pubmed citation
- 6. Ebrahim FS, De Maeseneer M, Jager T et-al. US diagnosis of UCL tears of the thumb and Stener lesions: technique, pattern-based approach, and differential diagnosis. Radiographics. 2006;26 (4): 1007-20. doi:10.1148/rg.264055117 - Pubmed citation