A Mayo Clinic orthopedic surgeon has discovered a common cause of debilitating wrist pain - a split tear of the UT ligament - that can be reliably detected through a simple physical examination and can be fully repaired through an arthroscopically guided surgical procedure.
The findings are published in the April issue of the American Journal of Hand Surgery.
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."