Mayo Clinic Solves Painful Puzzle Of UT Ligament Split Tear In Wrist

In the study of 272 consecutive patients (53.7 percent males, median age 33.7) with wrist pain who had undergone arthroscopy between 1998 and 2005, the Mayo Clinic team discovered that a positive "ulnar fovea sign" was highly effective in diagnosing either a complete ligament rupture or the newly described condition, a split tear of the ulnotriquetral (UT) ligament. The test involves pressing the ulnar fovea region of the patients' wrists (the side opposite the thumb) to determine tenderness. The researchers found a positive ulnar fovea test was 95 percent sensitive in revealing patients with a rupture or a UT split tear. The test's specificity was 86.5 percent.

Richard Berger, M.D., Ph.D., who led the study, says the UT split tear is a common but heretofore undefined injury, in which the wrist joint is stable but painful. "Typically, ligament injuries involve a rupture in which the ligament is completely severed," he explains. "The joint is unstable because the ligament is no longer holding the bones in their proper positions, and the crosswise rupture is easily visible through magnetic resonance imaging (MRI).

"The UT split tear is different, because the ligament is still attached to the bones on both ends, but is split open lengthwise," Dr. Berger continues. "The joint is stable, and the patient can have an MRI that would be interpreted as normal because there isn't a complete severing of the ligament. Even looking inside the joint with an arthroscope, the split tear isn't immediately obvious unless you know what to look for, and until now no one was looking for it because this type of injury hadn't been discovered. The diagnosis would have been called simple irritation or inflammation."

Dr. Berger says the split tear discovery came as "an epiphany," when he performed the ulnar fovea test on a patient while viewing the joint arthroscopically. "I saw that the source of the pain was exactly where I was pressing," he says. "When I cleared some of the blood vessel debris from the area, it became apparent that what had initially looked like a normal ligament was in fact split open lengthwise, so I was seeing the inside of the ligament."

As Dr. Berger performed the ulnar fovea test on subsequent patients and followed with arthroscopic examination, he noticed that a large majority of those with the positive ulnar fovea sign but stable joints had UT split tears.

"It's good news that this simple test is so effective at pinpointing the problem," he says. "What's even better is that we have a treatment that can restore full, pain-free function and improve quality of life for decades for these mostly younger patients."

Dr. Berger's treatment for a UT split tear uses arthroscopically guided surgery to suture the ligament and repair the split. After six weeks in a cast that immobilizes the wrist, the patient begins rehabilitation. Dr. Berger says the repair has been highly durable and has helped patients return to full strength at work or play within a few months after surgery.

"We've seen sheet metal workers and dairy farmers return to work," he says. "We've also had athletes restored: bowlers hurling a 16-pound ball, golfers, and even a major league baseball player. They seem good as new, and we haven't seen a risk of reinjury.

"The split tear of the UT ligament will help explain much of the wrist pain for which the cause previously had been unknown," Dr. Berger concludes. "It's especially gratifying to not only diagnose the reasons for the pain, but also to have such an effective treatment."

Other Mayo Clinic authors of the study include Shian Chao Tay, M.D., and Kazunari Tomita, M.D.