THUMB LIGAMENT TEAR
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What is a Skiier's Thumb (thumb ligament tear)?
Our ligaments connect one bone to another. They keep our bones in alignment and they prevent our bones from wobbling all over the place. Whenever two bones meet up they form a joint, and its the ligaments that hold the joint together and prevent dislocations.
Our thumb ligaments are especially important because our thumbs are so mobile and so busy every day. The thumb, also known as the opposable thumb, distinguishes humans from monkeys... among other things. The thumb is the stable foundation that other fingers lean on to perform daily functions. The thumb is not just strong but also highly mobile and enables fine dexterity.
This means that the bones in our thumb (there are three) are under constant stress and are always getting pushed one way or another. But they always stay in the same alignment because our thumb's ligaments are very strong and sit on all sides of the bones to prevent instability.
However, if the thumb is bent too far to the side, a ligament can tear. The most common thumb ligament to tear is the Ulnar Collateral Ligament (UCL) of the thumb (it connects the 1st metacarpal bone with the proximal phalanx, see picture). This ligament prevents your thumb from being bent too far away from your hand.
A UCL tear got the nickname "Skiier's Thumb" because when someone falls while holding a ski pole, the pole can forcefully push your thumb away from the hand, causing this type of injury. The vast majority of people that tear their thumb ligament are not skiing, and are doing something much less exciting, like cleaning the attic.
Another nickname for this injury is a "Stener Lesion" which is less memorable than Skiiers thumb because Dr. Stener was a pretty boring guy (unless he got to talking about thumb ligaments).
How is a Skiier's Thumb (thumb ligament tear) diagnosed?
A Thumb Ligament Tear usually occurs after a fall, and people will report significant pain and swelling.
Doctors will examine the injured thumb and test the stability of the thumb at each of its joints (remember that ligaments live around joints, because they connect one bone to another). The collateral ligaments prevent the thumb from bending too far to the side (especially when the thumb is flexed forward). The thumb joint (called the MCP) is bent away from the hand by the doctor to determine if there is a healthy ligament keeping the bones aligned. Excessive bending suggests that the ligament is torn.
X-rays are ordered because thumb pain and swelling also occurs with a broken thumb (see talk) and ruling out a break is an important part of diagnosing a ligament injury.
Ligaments don't show up on x-ray and so this injury isnt usually seen on x-ray. On some occasions, when the ligament tears off of the bone, it actually pulls off a small piece of bone with it, and this can be seen on x-ray (a little chip of bone). Sometimes, the thumb bones don't line up correctly on x-ray, so even though you cant see a torn ligament, you know something is wrong.
In many cases, doctors are suspicious for the injury because the thumb is painful and swollen, and its a little bit unstable (it bends too far), and so they will order an MRI, which is a better test for looking at ligament injuries.
Diagnosis is made by examining the finger, by getting x-rays and some times after also getting an MRI.
How is a Skiier's Thumb (thumb ligament tear) treated?
Treatment depends on how badly the thumb ligament was injured.
If the ligament is only partially torn but still attached to thumb bone, it can be protected in a splint (or cast) for a few weeks while it has time to heal.
When the ligament completely tears, it gets caught up in another layer of soft tissue (called the adductor aponeurosis) and it cannot return to its insertion site without some help from your Hand Surgeon. Surgery involves untangling the ligament from this surrounding tissue and re-attaching it onto the thumb bone so it can stabilize the thumb's MCP joint.
What is the long term outcome?
This injury typically needs surgery to heal correctly and the results are usually good if treated soon after the injury.
Most surgeries are successful at returning stability to the thumb and preventing pain with daily activities.
The biggest problem with this injury occurs when its not diagnosed soon after the tear. Our ligaments only have a limited amount of time (a few weeks) to heal. After a few weeks, our body is done fixing itself and you get what you get. This means that any instability recognized months later need a more complex surgery for repair. You cannot simply re-attach the ligament, but need to use a graft (substitute for the real thing) or just fuse the MCP joint. These are more complicated procedures, with a higher rate of complications.
1) Tang P. Collateral ligament injuries of the thumb metacarpophalangeal joint. JAAOS 2011; 19: 287-96. full article. review.
2) McKeon KE et al. Ulnar collateral ligament injuries of the thumb: phalangeal translation during valgus stress in human cadavera. JBJS 2013; 95: 881-7. full article. phalangeal translation occurs in complete tear (proper + accessory), increased angulation occurs in partial (proper only).
3) Milner CS et al. Gamekeeper's thumb - a treatment-oriented magnetic resonance imaging classification. J Hand Surg 2015; 40: 90-5. full article. minimal displaced complete tear (<2 mm) heal nonop, >3 mm or stener lesion req. surgery.
4) Campbell CS. Gamekeeper's thumb. JBJS Br 1955; 37: 148-49. full article classic paper. describes in scottish people that used hand to break neck of injured rabbits after hunting.
5) Stener B. Displacement of the ruptured ulnar collateral ligament of the metacrapophalangeal joint of the thumb: a clinical and anatomical study. JBJS Br 1962; 44: 869-79. full article. classic paper.