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Gamekeepers Thumb

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Other Names

  • Ulnar Collateral Ligament (Thumb) Injury
  • Skier's Thumb
  • Ulnar Collateral Ligament of the Thumb Injury
  • UCL Injury
  • Thumb Collateral Ligament Injury




  • 10 fold more common than injuries to the RCL of thumb (need citation)
  • Represents 86% of all athletic thumb injuries (need citation)


  • General
    • Characterized by avulsion or rupture of the UCL of the thumb
    • UCL: Protects medial side of MCPJ of thumb
  • Chronic
    • Historically, injury was seen in 'gamekeepers' from repetitive breaking of rabbit necks
    • This was a more insidious, degenerative condition
  • Acute
    • Now more commonly seen in skiers, sports
    • Typically an acute injury
    • Stock-strap forcibly abducting thumb during a fall or plant maneuver with exaggerated extension abduction


  • General
    • Radial directed force causing hyperabduction of the Thumb MCPJ

Associated Conditions


Risk Factors

  • Male > Female [1]
  • Sports
    • Alpine Skiing
    • Football
    • Soccer

Differential Diagnosis

Clinical Features

Illustration of how to perform the UCL stress test.[2]
  • History
    • Primarily a clinical diagnosis
    • Patients will report pain at the 1st MCPJ
    • Typically worse with abduction or extension
    • Swelling, ecchymosis may be present acutely
    • Fall on outstretched hand with abducted thumb
  • Physical Exam: Physical Examination Hand
    • Minimal swelling, bruising
    • No deformity
    • Tenderness at site of UCL injury, typically on the phalanx
    • If palpable mass, consider stener lesion
  • Special Tests
    • UCL Stress Test (Thumb): Valgus stress causes pain, laxity (> 15-20° typically considered pathologic)
    • Complete tears will lack an endpoint
    • Important to compare to unaffected thumb


Thumb US showing loss of continuity of the UCL, widening of the joint space under controlled stress[3]


  • Standard Radiographs Hand
    • May be normal
    • Evaluate for avulsion injury
    • May see joint space widening
  • Consider stress views
    • Controversial, not widely used


  • Can be helpful to evaluate tear
  • May identify stener lesion
  • Can dynamically stress the UCL


  • Indications
    • Not always required
    • Aid in diagnosis if equivocal history and exam
    • Can help if other soft tissue injuries suspected
  • Diagnostic accuracy (need citation)
    • Sensitivity 100%
    • Specificity 100%


Hintermann Classification

  • Type I: Fracture which is non-displaced, stable in flexion
  • Type II: Displaced fracture
  • Type III: No fracture, joint is stable in flexion
  • Type IV: No fracture, unstable
  • Type V: Fracture present, involving the volar plate, stable in flexion
  • Type VI: Fracture present, involving the volar plate, unstable

UCL/RCL Instability Grading

  • Grade 1
    • Sprain with no joint instability
    • Tear: Incomplete tear
  • Grade 2
    • Asymmetric joint laxity but endpoint present
    • Tear: incomplete tear
  • Grade 3
    • Joint instability without endpoint
    • 30-35 degrees of joint space opening or 10-15 degrees more than contralateral thumb
    • Tear: complete tear



  • Return to play
    • In grade I/II, there is an excellent return to play rate (need citation)
    • Approaches 100% following anatomic repair (need citation)


  • Indications
    • Generally driven by an absence of displacement or instability
    • Most type instability grade I, II
    • Most Hinterman Type I, III, V lesions
  • Immobilization
  • Eventually begin rehabilitation


  • Indications
    • Hinterman: Type II, IV, VI lesions
    • Valgus laxity >15-20°
    • Stener Lesion
  • Technique
    • Reconstruction with tendon graft
    • Adductor advancement
    • MCP fusion or adductor advancement

Rehab and Return to Play


  • Needs to be updated

Return to Play/ Work

  • Needs to be updated


  • Stener Lesion
  • Stiffness
  • Persistent instability
  • Superficial radial neuropraxia

See Also



  1. Chuter GS, Muwanga CL, Irwin LR. Ulnar collateral ligament injuries of the thumb: 10 years of surgical experience. Injury. 2009 Jun;40(6):652-6
  2. Leggit JC et al. Acute finger injuries: Part II. Fractures, dislocations, and thumb injuries. Am Fam Physician. 2006;73(5):827-834
  3. https://radiopaedia.org/cases/gamekeeper-thumb-4?lang=us
Created by:
John Kiel on 18 June 2019 23:14:29
Last edited:
16 October 2022 00:20:15