Ulnar collateral ligament (UCL) injuries of the thumb can be a cause of pain, instability or weakness of the thumb. Most often people will remember an injury or event that caused the problem, but occasionally it will come on gradually with no identifiable injury. UCL injuries can usually be managed with hand therapy alone but some will need an opinion from a surgeon. It is important to get these injuries treated as they can cause pain and disability in the long-term if they are not managed well.


The UCL of the metacarpo-phalangeal joint of the thumb is located on the inside edge of the middle joint of the thumb. This is the joint at the base of the thumb where it attaches to the hand. It is the job of the UCL to prevent sideways movement of the thumb and it is especially important when you try to grasp an object or take pressure through the tip of the thumb in pinching. The ligament on the outside edge of this joint is called the radial collateral ligament (RCL) and is less commonly injured.

An injury may involve damage to the fibres of the ligament itself, or else the ligament may pull off a piece of bone where it attaches. This is called an avulsion fracture.

Ligament injuries are classically divided into three categories:

  • Grade 1 injury: the ligament is strained, but intact with relatively normal resistance to forces (“no laxity”)
  • Grade 2 injury: the ligament is partially torn with reduced resistance to forces (“increased laxity”)
  • Grade 3 injury: the ligament is completely ruptured.


A thumb UCL injury can result from a fall onto an outstretched hand that causes the thumb to bend away from the palm or from a blow to the inside of the thumb, for example from a ball.  A thumb UCL injury is common in sports such as skiing, snowboarding, basketball, football etc. Thumb UCL injuries are commonly known as Skier’s Thumb, this is because a ski pole can push the thumb outward if it is caught in the snow or in a fall. It is also sometimes called Gamekeeper’s Thumb.

Signs & Symptoms

Pain is a common symptom of a thumb UCL injury, however, some are completely pain free and you should still seek treatment if this is the case. Other common symptoms include:

  • Pain that worsens when moving your thumb
  • Bruising, swelling, and tenderness at the base of the thumb
  • Thumb feels loose and not secure
  • Weakness when gripping or squeezing with the thumb and index finger
  • A lump and swelling on the inside of the thumb

A hand therapist will be able complete a physical exam to assess the injury and stability of the thumb. They may then recommend medical imaging such as X-ray, Ultrasound or MRI for further assistance in diagnosing and grading the injury. Depending on the imaging, this may need to be ordered by your GP.


Partial tears can be treated conservatively by a hand therapist with the fabrication of a custom made thermoplastic splint.  Depending on the severity of the injury this may be required for 4-6 weeks full time. After this, the therapist will assist with exercises aimed at regaining movement and strength.

Complete tears are likely to require surgical reattachment.

Melbourne Hand Therapy Can Help You

Our therapists at Melbourne hand therapy are experts at managing this injury from the acute phase through to the rehabilitation phase. Our aim is to heal the injury as quickly as possible and work with you to ensure you can return to all normal functional activities including work, sports and recreation. We work closely with Melbourne’s best hand surgeons and can organise a timely referral if surgery is required.


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