Simple test helps diagnose ulnar-sided wrist pain caused by certain ligament injuries

A positive ulnar fovea sign may indicate a distal radioulnar ligament disruption or a ulnotriquetral ligament injury.

Split tears of the ulnotriquetral ligament, a common cause of severe wrist pain, can be reliably detected through a simple physical examination, according to a study by researchers at the Mayo Clinic in Rochester, Minn.

Richard A. Berger, MD, and colleagues investigated whether the presence of ulnar fovea tenderness, or the ulna fovea sign test, could detect foveal disruption of the distal radioulnar ligaments as well as ulnotriquetral (UT) ligament injuries, according to the study, published in the American edition of the Journal of Hand Surgery.

The test involves applying pressure to the ulnar fovea region of patients' wrists to detect tenderness. Specifically, the physician presses his or her thumb between the ulnar styloid process and flexor carpi ulnaris tendon, and between the volar surface of the ulnar head and pisiform, the authors reported.

"A positive ulnar fovea sign is designated when there is exquisite tenderness that the patient claims replicates their pain, with comparisons made with the contralateral side," they wrote.

To determine the sensitivity and specificity of the test, Berger and colleagues reviewed records for 272 consecutive patients who underwent wrist arthroscopy between 1998 and 2005. Patients averaged 33.7 years of age, and most were men (53.7%), according to a press release from the Mayo Clinic announcing the study findings.

Using arthroscopy, the surgeon identified 90 foveal disruptions and 68 UT ligament injuries. Of these 158 cases, 156 had a positive ulnar fovea sign preoperatively, according to the study.

The researchers found a positive ulnar fovea test was 95% sensitive and 86.5% specific for detecting a foveal disruption or a UT split tear, the press release said.

"Typically, ligament injuries involve a rupture in which the ligament is completely severed," Berger said in the release. "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 ... but is split open lengthwise," he said.

"The joint is stable, and the patient can have an MRI that would be interpreted as normal because there is not a complete severing of the ligament. Even looking inside the joint with an arthroscope, the split tear is not 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," Berger said in the release.

For more information:
Tay SC, Tomita K, Berger RA. The "ulnar fovea sign" for defining ulnar wrist pain: An analysis of sensitivity and specificity. J Hand Surg [Am]. 2007;32:438-444.