Metacarpophalangeal ulnar ligament rupture

Background

• Also known as "Gamekeeper's thumb" or "Skier's thumb"
• Ulnar collateral ligament ruptures at insertion into proximal phalanx (due to radial deviation of MCP)
• If left untreated, it will causes decreased thumb adduction and inability to perform opposition.
• The mechanism of injury is usually a rapid deceleration while holding onto an object (such as a ski pole)

Clinical Features

• Swelling and localized tenderness over ulnar border of the thumb MCP joint
• Weakness of pinch

Differential Diagnosis

Hand and finger injuries

• Radiograph positive
  • Hand and finger fractures
  • Hand and finger dislocations
  • Triquetrolunate ligament instability
• Radiograph negative
  • Dupeytren contracture
  • Boutonniere deformity
  • Hand and finger tendon injuries
  • Ganglion cyst
  • De Quervain tenosynovitis
  • Intersection syndrome
  • Drummer's wrist
  • Extensor digitorum tenosynovitis
  • Vaughn Jackson syndrome
  • Snapping Extensor Carpi Ulnaris
  • Compressive neuropathy, "bracelet syndrome"
  • Scaphoid fracture
  • Osteoarthritis
  • Infiltrative tenosynovitis
  • Gout
  • Rheumatoid arthritis
  • Trigger finger
  • Mallet finger
    • Swan neck deformity
  • Jersey finger
  • Jammed finger
  • Subungual hematoma
  • Fingertip laceration
  • Metacarpophalangeal (MCP) ulnar ligament rupture (Gamekeeper's thumb)
  • Nail avulsion
  • High-pressure injection injury

Evaluation

• X-ray (perform before joint stressing)
  • There is a high association with avulsion fractures from insertion of UCL into proximal phalanx
  • Proximal phalanx volar subluxation and radial deviation suggests complete UCL rupture
• Apply radial stress to the thumb with MCP in partial flexion
• Compare relative laxity to other thumb.
• >35 degrees of joint laxity or 15 degrees of releative laxity compared to other thumb is diagnostic of a complete UCL rupture

Stener Lesion

This phenomenon occurs when there is a UCL tear that results in entrapment of the adductor pollicis aponeurosis within the UCL. Clinically characterized by extensive laxity on stress testing of the thumb MCP. Patients will require surgical repair

Management

All patients with suspected UCL injury should be referred for a hand surgeon within 1 week. Reevaluation will dictate operative managment

• Partial rupture
  • Immobilization in thumb spica for 4 weeks with thumb in neutral position
• Full rupture or Stener lesion
  • Operative repair

Disposition

• Outpatient treatment

See Also

• Hand and finger injuries

References

Authors

Ross Donaldson, Neil Young