Health Information

Ulnar Collateral Ligament Injury of the Thumb

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Ulnar Collateral Ligament Injury of the Thumb (by Clare Black)

Ulnar Collateral Ligament Injury of the Thumb


Mechanism of Injury

An ulnar collateral ligament injury of the thumb occurs when the thumb is forcibly stretched away from the hand causing a strain, partial or full thickness tear of the ligament or an avulsion fracture.

UCL injury.jpg

Photo source: Hand and Wrist Institute



  • Pain and swelling over the ulnar collateral ligament at the metacarpophalangeal joint of the thumb.
  • Instability or laxity on the ulnar side of the metacarpophalangeal joint of the thumb.
  • Weakness and difficulty gripping and pinching.




A physical assessment of the thumb is required to determine if there is any laxity of the thumb metacarpophalangeal joint in comparison to the uninjured thumb.


An x-ray is usually recommended to confirm if a fracture is present. An ultrasound or MRI may also be used to confirm the extent of the injury to the ulnar collateral ligament.

Ulnar collateral ligament avulsion fracture .jpg

Ulnar collateral ligament avulsion fracture 

Photo source: Orthobullets




A referral to a hand therapist should be made as soon as the injury is diagnosed, preferably within 7 days post-injury. If there is a large avulsion fracture, a referral to a hand surgeon is recommended as soon as possible.


Conservative Management

  • A custom-made thermoplastic thumb splint is commonly required for approximately 4-6 weeks, depending on injury severity.
  • Pain and oedema management.
  • Advice regarding activity modification.
  • Early mobilisation of the thumb interphalangeal joint and wrist.
  • As the ligament heals a graded exercise program to regain thumb metacarpophalangeal movement and strength will be prescribed.