Skier's thumb is a tear of the ligament on the inner side of the thumb's knuckle joint, the ligament that anchors pinch. It happens when the thumb is wrenched outwards: a ski pole in a fall, bicycle handlebars, a ball, or a hand put out to break a fall. It is a common injury and it is often dismissed as a sprain. That matters, because a fully torn ligament often cannot heal on its own, and an unstable thumb loses the pinch strength it needs for keys, jars and tools. Seen early, the ligament can be repaired directly as a day procedure. Seen late, it can still be fixed, with a reconstruction rather than a repair.
What is skier's thumb?
The metacarpophalangeal or MCP joint is the knuckle of the thumb, between the long bone in the palm and the first bone of the thumb itself. On its inner side, facing the index finger, lies the ulnar collateral ligament.
A sudden force that bends the thumb outwards stretches the ligament beyond its limit. It can tear partly, leaving the joint sore but stable, or completely, usually from the bone at the thumb end, sometimes taking a flake of bone with it.
With a complete tear the torn end can flip back and come to lie on top of a flat tendon sheet that crosses the joint, which then sits between the ligament and the bone it needs to heal to. This is called a Stener lesion. The ligament cannot reach its attachment, so no amount of splinting will heal it, and it is the main reason a complete tear is treated surgically.
Skier's thumb describes the acute injury. Gamekeeper's thumb is the older name for the same ligament stretched gradually by repeated strain, now used for any longstanding instability of the joint.
Symptoms
Most people describe:
- Pain and swelling on the inner side of the thumb knuckle after a fall or a wrench
- Bruising spreading into the web between thumb and index finger over a day or two
- Weakness and pain on pinch: turning a key, opening a jar, holding a pen
- A feeling that the thumb gives way or wobbles when it is loaded
- Sometimes a small firm lump on the inner side of the joint, which can be the flipped ligament end
Causes and risk factors
Falls while skiing, with the pole levering the thumb outwards, gave the injury its name. We see it more often from cycling and motorbike falls, and from football, netball and basketball where a ball strikes the thumb. The chronic form is seen where work or sport loads the thumb repeatedly: shearing, manual trades and racquet sports.
How it is diagnosed
By examination, with an X-ray first. The X-ray shows whether a piece of bone has been pulled off with the ligament and whether it has moved, and it is taken before the joint is stressed.
We then test the ligament by gently pushing the thumb away from the hand with the joint straight and with it bent, and compare it with your other thumb. A partial tear is painful but the joint stops at a firm end point. A complete tear opens further, by 30 degrees or more, or 15 degrees more than the other side, with a soft end point.
Where the examination suggests a complete tear, an ultrasound shows whether the ligament end has flipped into a Stener position. We use ultrasound in preference to MRI for this, and reserve MRI for the uncertain case.
Non-surgical treatment
Partial tears, and complete tears where the ligament is still lying in place, can heal in a splint, and many do.
Splinting
A thumb spica splint, which holds the thumb knuckle still while leaving the tip free, is worn for four to six weeks. For the first two to three weeks it stays on apart from skin care. After that it comes off for gentle movement exercises and goes back on for everything else. Pinching and gripping against resistance wait until eight to twelve weeks from injury.
Hand therapy
Our hand therapists make the splint, protect the skin, start the joint moving at the right time and rebuild pinch strength with a graded programme. The splint is fitted the same week, on site.
When surgery is needed
We advise surgery where:
- The ligament is completely torn, with no firm end point on examination
- Ultrasound shows a Stener lesion
- A fragment of bone has come away and has rotated or moved
- The thumb remains unstable after splinting, or the instability is longstanding and causing weakness, pain or giving way
Early repair, within three weeks of the injury, gives the most predictable result. The injury should not sit under strapping for a month to see how it goes.
The operation
Ligament repair is done through a short incision on the inner side of the thumb knuckle. A sensory nerve branch to the back of the thumb runs directly across this area and is found and protected first. The flipped ligament end is retrieved and brought back to its bed, and it is reattached to the bone with a small suture anchor. In some cases the repair is reinforced with a strong suture tape across the joint, which lets the thumb move earlier. The skin is closed and a plaster thumb spica goes on.
For a longstanding injury, where the ligament has scarred and shortened, a direct repair is not possible. The ligament is reconstructed using a spare tendon from the forearm, passed through small tunnels in the bone and tensioned to hold the joint. Where the joint has already become arthritic, fusing the thumb knuckle is the more reliable option.
Repair is a day surgery procedure using sedation with a local anaesthetic block, taking approximately 30 to 45 minutes. A reconstruction takes approximately 60 minutes and is usually done under a general anaesthetic.
Recovery, week by week
Indicative, for a ligament repair. After a reconstruction the splinting stages are a little longer.
Day of surgery. Thumb and hand numb for up to 24 hours from the block. Plaster thumb spica on. Keep the hand up and move the fingers.
Days 10 to 14. Review, and sutures removed. The plaster is replaced by a custom thermoplastic thumb spica fitted by your hand therapist. Gentle bending of the knuckle starts out of the splint.
Two to four weeks. Splint worn at all times except exercises and washing. Fingers used freely. Office work and writing are manageable with the splint on.
Four to six weeks. Splint weaned by day, worn at night and for protection. Driving usually resumes once the splint is off four to six weeks.
Six to eight weeks. Splint discarded. Pinch strengthening with the therapist. Light manual work resumes.
Ten to twelve weeks. Return to sport, cycling and heavy manual work, taped at first ten to twelve weeks. Strength and comfort keep improving for months.
Risks and complications
Thumb ligament repair is routine and safe. Problems are uncommon and include:
- Numbness or tingling on the back of the thumb from irritation of the sensory nerve branch that crosses the incision. Usually temporary, occasionally permanent.
- Stiffness of the thumb knuckle, the most common issue, which therapy minimises and which rarely affects function because the joint needs little movement.
- Persistent laxity or re-rupture, uncommon after a sound repair, more likely if the thumb is loaded too early.
- Infection, usually superficial, treated with antibiotics.
- Arthritis of the joint in later years, related to the joint damage at the time of injury.
When to be seen sooner
Contact us, or see your GP, if you have:
- A thumb that has been strapped for a sprain and still gives way or hurts to pinch after two to three weeks
- A lump on the inner side of the thumb knuckle after an injury
- An X-ray showing a fragment of bone at the knuckle
- Numbness, increasing pain or redness after surgery
If you have had surgery with us and have questions or concerns afterwards, phone the rooms during office hours on (08) 7127 0365.
Frequently asked questions
Is it not just a sprain?
It may be. A partial tear is a sprain, and it heals in a splint. The problem is that a complete tear feels the same in the first week, and if it has flipped out of position it will not heal at all. An examination and an X-ray tell the two apart, and the cost of being wrong is a permanently weak thumb.
What is a Stener lesion?
The torn end of the ligament has flipped back and is lying on top of a flat tendon sheet instead of against the bone. The sheet sits between the two, so the ligament can never reach its attachment and heal.
How long will I be out of sport?
About ten to twelve weeks after surgery for contact sport, skiing, cycling and racquet sports, taped for the first few weeks back.
When can I drive and go back to work?
Driving usually resumes when the splint comes off, at four to six weeks, once you can control the car safely, including in an emergency. Office work is manageable within a week or two, splinted. Light manual work at about six to eight weeks, and heavy manual work at ten to twelve weeks. We will give you a realistic estimate for your job and a certificate.
My injury was months ago. Is it too late?
No. A repair is no longer possible once the ligament has scarred and shortened, but a reconstruction with a tendon from the forearm restores stability reliably. If the joint has become arthritic in the meantime, a fusion is the alternative.
Do I need a referral?
Yes for a consultation with one of our surgeons: a referral from your GP, an emergency department or another specialist. No referral is needed for hand therapy, and a therapist who finds an unstable thumb will arrange for one of our surgeons to see you promptly.
Written and clinically reviewed by Dr Paul van Minnen, MD, PhD, EBOPRAS, FRACS (Plast)
Last reviewed 8 November 2026