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Ulnar collateral ligament rupture of 1st MCP Joint (Skier’s Thumb)
Understanding injuries to the main stabilising ligament of the thumb, sometimes called gamekeeper’s thumb or skier’s thumb, and how they are treated.
What is a first Metacarpophalangeal Joint Ulnar Collateral Ligament Rupture (Skier's Thumb or Gamekeeper's Thumb)?
The ulnar collateral ligament (UCL) stabilises the thumb’s main knuckle joint (the 1st metacarpophalangeal joint, or MCPJ) against sideways force during pinch and grip. This ligament can be torn by a fall onto an outstretched thumb, classically while holding a ski pole, giving the injury its other name, skier’s thumb.
The ligament commonly tears off the bone, but can also be avulsed with a bone fragment of variable size. The older name, gamekeeper’s thumb, comes from a similar chronic injury once seen in gamekeepers from repeatedly wringing the necks of game birds.
1st MCPJ UCL Rupture (Skier's Thumb) at a glance
What is it?
A complete tear of the ulnar collateral ligament that stabilises the thumb's main knuckle joint
Common symptoms
Pain, swelling and bruising at the base of the thumb, with a weak or unstable pinch grip
Who it affects
People who sustain trauma to the thumb or fall onto an outstretched thumb, often during skiing or ball sports
Is it serious?
A complete tear usually needs surgical repair to avoid lasting instability and early arthritis
Treatment options
Splinting for partial tears, or surgical repair for complete tears
First step
An examination and imaging to determine how severe the tear is
Symptoms and how 1st MCPJ UCL Rupture (Skier's Thumb) presents
The main symptoms are pain, swelling and bruising at the base of the thumb, with tenderness on the palm side of the thumb’s main knuckle. Pinch grip is often weak and painful, and some people notice a feeling that the thumb is unstable or giving way.
Causes and risk factors for 1st MCP Joint Ulnar Collateral Ligament Rupture (Skier's Thumb)
- Football (AFL or soccer) injury
- A fall onto an outstretched thumb
- Skiing injuries, from a fall onto a ski pole
- Ball sports injuries
- Forceful sideways bending of the thumb
How is 1st MCP Joint Ulnar Collateral Ligament Rupture (Skier's Thumb) diagnosed?
Diagnosis involves examination, including gently stress testing the joint to check for sideways movement, along with an x-ray to check for an associated small bone fragment. Ultrasound, or occasionally MRI, is often performed prior to your appointment with a hand specialist to assess whether the ligament is fully or partially torn, and whether the torn end has become trapped out of place (a Stener lesion), which affects the chance of it healing without surgery.
The diagnosis also considers whether the ligament itself has ruptured, which generally involves the ligament pulling off its insertion to the bone, or whether the bone that the ligament inserts into has broken. The latter injury is technically a fracture, because the part that needs to heal is a broken bone. The mechanics of the thumb instability is the same, but the treatment and rehabilitation varies according to the specific nature of the injury.
Treatment options for 1st MCP Joint Ulnar Collateral Ligament Rupture (Skier's Thumb)
Partial tears without instability are routinely treated successfully with a thermoplastic splint under the guidance of a hand therapist to allow the ligament to heal in position. The duration of splinting and time to return to full activity varies according to the severity of the initial injury, and your response to treatment.
Complete tears, particularly those with a Stener lesion, generally need surgical repair, since the separated ligament ends are held apart in a way that prevents natural healing.
When to see a hand surgeon about 1st MCP Joint Ulnar Collateral Ligament Rupture (Skier's Thumb)
Any thumb injury with pain, swelling and difficulty pinching after a fall or sporting injury should be assessed, ideally promptly, since a complete tear is treated more successfully soon after the injury occurs.
What to expect at your 1st MCP Joint Ulnar Collateral Ligament Rupture (Skier's Thumb)
At your appointment, Dr Tomlinson will examine your thumb, including stress testing the joint, and arrange imaging as indicated. Together you will discuss whether splinting or surgery is the right treatment for your injury. If you have not already been seen by a hand therapist you will be provided with a referral to one.
Frequently Asked Questions
What is a UCL rupture of the thumb (Skier's Thumb)?
The ulnar collateral ligament (UCL) stabilises the thumb’s main knuckle joint (the 1st metacarpophalangeal joint, or MCPJ) against sideways force during pinch and grip. This ligament can be torn by a fall onto an outstretched thumb, classically while holding a ski pole, giving the injury its other name, skier’s thumb. The ligament commonly tears off the bone, but can also be avulsed with a bone fragment of variable size. The older name, gamekeeper’s thumb, comes from a similar chronic injury once seen in gamekeepers.
What causes it?
This injury is most often caused by a fall onto an outstretched thumb, such as during skiing (a fall onto a ski pole), football or other ball sports, or any forceful sideways bending of the thumb.
What can I do myself?
Any thumb injury with pain, swelling and difficulty pinching after a fall or sporting injury should be assessed, ideally promptly, since a complete tear is treated more successfully soon after the injury occurs.
What can a hand therapist do?
Partial tears without instability are routinely treated successfully with a thermoplastic splint under the guidance of a hand therapist, allowing the ligament to heal in position. The duration of splinting and time to return to full activity varies according to the severity of the initial injury and your response to treatment.
What can a hand surgeon do?
Dr Tomlinson will examine your thumb, including stress testing the joint, and arrange imaging as indicated. Complete tears, particularly those with a Stener lesion (where the torn ligament end becomes trapped out of place), generally need surgical repair, since the separated ligament ends are held apart in a way that prevents natural healing.
What can I expect from treatment?
At your appointment, Dr Tomlinson will examine your thumb and arrange imaging as indicated. Together you will discuss whether splinting or surgery is the right treatment for your injury. If you have not already been seen by a hand therapist, you will be provided with a referral to one.
What happens if it's left untreated?
A complete tear usually needs surgical repair to avoid lasting instability. Diagnosis and treatment soon after the injury gives the best chance of a good outcome, which is why any thumb injury with pain, swelling and difficulty pinching after a fall should be assessed promptly.
Related conditions and treatments
This ligament injury affects the thumb. For a similar but separate ligament injury at the wrist, see wrist ligament injury and instability. A broken bone at the base of the thumb can occur alongside this injury, see hand fractures.