Gamekeeper Thumb Clinical Presentation

Updated: Apr 18, 2016
  • Author: Michael A Secko, IV, MD; Chief Editor: Trevor John Mills, MD, MPH  more...
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Presentation

History

Patients may complain of pain, swelling, and/or ecchymosis of the MCP joint after a fall or blow to the thumb, forcing it into a combination of hyperextension and radial (lateral) deviation. This commonly occurs while participating in sports but has been noted in patients who fall on outstretched hands and in motor vehicle accidents. The most common mechanism is a fall while holding onto a ski pole. This injury can also be seen in a football player forcibly abducting and hyperextending a thumb while holding back a rushing opponent.

Patients may also complain of weakness or worsening pain when pinching the thumb against the index finger when no acute injury is reported.

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Physical

The injured thumb should be evaluated for pain, point tenderness, ecchymosis, and/or swelling, specifically on the ulnar aspect of the MCP joint.

A palpable mass on the ulnar aspect of the MCP joint may be obvious and may represent the ruptured UCL that is abnormally displaced proximally and dorsally relative to the adductor aponeurosis.

Standard radiographs should be obtained before lateral stress examination, because stress testing may cause further displacement of an avulsion fracture that was originally minimally displaced.

Valgus (lateral) stress testing can determine the integrity of the UCL. Stability of the opposite thumb should be tested as well for comparison.

Stress examination is performed while stabilizing the thumb metacarpal with one hand to prevent rotation. The thumb should be placed in 30° flexion, and a lateral (radial) stress should be applied on the joint.

A displaced avulsion fracture is a contraindication to stress testing but a nondisplaced fracture is not.

Administration of local anesthetic may be necessary to facilitate optimal examination. This can be accomplished by either a local injection of 1% lidocaine into the MCP joint or by blocking the sensory branches of the radial and median nerves at the wrist.

Laxity (angulation) of more than 35° or laxity 15° more than the uninjured side suggests a complete rupture of the proper collateral ligament. Laxity (angulation) less than 35° or comparative laxity less than 15° probably denotes an incomplete rupture.

The accessory collateral ligament may remain intact, and gross instability may not be present. Therefore, examination in extension should be performed. Reports have demonstrated that laxity of the MCP joint in extension when stressed, consistently indicates tears of the proper and accessory collateral ligaments and is more commonly associated with a Stener lesion. Laxity of more than 35° or laxity of 15° more than the uninjured side may suggest rupture of the accessory collateral ligament.

If lateral (valgus) laxity of the MCP joint exists for both the flexed and extended positions, then complete rupture of the UCL should be suspected, and greater possibility of a Stener lesion exists.

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Causes

Fall onto outstretched hand causing a forced abduction and extension of the thumb

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