Surgery On Decline For ‘Skier’s Thumb’ Magnetic Resonance Imaging Lets Doctors Diagnose Torn Ligaments More Accurately

Radiologists think they can lend surgeons a helping hand by preventing unnecessary operations for a condition called “skier’s thumb.”

Computerized pictures could show which cases need surgery and which don’t, Dr. Charles P. Ho told a meeting of the Radiological Society of North America.

The injury happens when the skier’s hand is trapped on a pole that is stuck in the ground.

As the moving hand is jerked away from the pole, the thumb is caught behind the pole, then pulled down and to the rear of the hand, he said. This rips the ligament in the web space between the thumb and index finger, he said.

If the ligament is still attached to the bone, it can heal itself after the hand is put in a cast, Ho said. But if the ligament has torn free, surgeons may need to reattach it, he said.

Incomplete tears are easy to diagnose, said Dr. William Sterett, a partner in the Steadman-Hawkins Clinic of Vail, Colo. But diagnosing complete tears is more difficult, because the thumb may or may not heal properly, he said.

“If there appears to be instability, we will always operate,” said Dr. Matthew Troiano, a hand specialist at the University of Pittsburgh Medical Center. It’s possible for another tendon to slip into the space where the injured tendon should be, which makes proper healing impossible, he said.

In either complete or incomplete tears, the hand must remain in the cast for a month, and physical therapy is prescribed as a followup.

After knees, the thumb is the most commonly injured body part in skiing, Ho said. He estimated there are thousands of such injuries every year.

Doctors have to operate when they are in doubt because X-rays and physical examination can’t be counted upon to tell loose ligaments from the detached ones, Ho said.

However, Ho said the study indicates magnetic resonance imaging can be used to make a proper diagnosis. The equipment is more capable than X-rays when it comes to identifying ligaments from other internal structures.

The study looked at MRI results on 34 people, 25 of them injured skiing. The other nine were uninjured. All 25 injured people were operated on.

Radiologists were given images of the hands of all the patients, and told to find the people who needed the operation. The results were compared with the surgeons’ assessments. The agreement between the radiologists and surgeons was above 90 percent. “With MR screening, six of the patients could have been spared surgery,” Ho said.

Imaging also would have saved a lot of money, Ho said. Two images of the hand can be made in 20 minutes, so the bill for preventing unneeded surgery would have been $300, he said. Surgery and follow-up care can cost $10,000 or more, he said.

Exercise won’t prevent the injury, but up-to-date ski poles can reduce the chances, said Troiano. Older poles, and poles used by competitive skiers, have rings instead of straps, and the rings can make it harder to pull the hand out of danger, he said.

“When I ski, I don’t use the straps or anything.”

Keeping the thumb out of the pole strap is the safest way to hold the pole, said Sterett.

Troiano said a skier also can reduce the risk of injury by keeping the hand clenched when falling, so the thumb can’t be stretched out of joint.