2007

Newly Defined Clinical Examination Identifies Common Cause of Ulnar-Sided Wrist Pain

Points to Remember

• Injuries to the ulnotriquetral (UT) ligament are common sources of ulnar-sided wrist pain, usually associated with high-torque swing sport rotation.
• Research by the Mayo Clinic orthopedic surgery team identifies a previously overlooked but frequent cause of ulnar-sided wrist pain — an axial "split tear" of the UT ligament.
• Split tears, rarely seen on MRI of the wrist, can be diagnosed with 95% sensitivity by a simple clinical exam finding described by Mayo Clinic orthopedists.
• Full, pain-free wrist function of the previously undiagnosed problem can be restored by arthroscopically guided repair of the split tear.

The Challenge

In the past, finding the source of debilitating wrist pain associated with high-torque "swing sports" such as golf and baseball has usually been difficult. In some cases, complete separation of the triangular fibrocartilage complex from the ulna or a crosswise rupture of the ulnotriquetral (UT) ligament (both causing joint instability) was found to be the cause of the pain. In these typical cases of UT ligament injury, the finding of an unstable wrist and typical MRI findings made the diagnosis apparent. But in many patients without typical findings, a definitive cause of pain was never identified, resulting in relatively poor clinical outcomes. The recent discovery and description of an axial "split tear" of the UT ligament by a Mayo Clinic orthopedic surgery team help explain the cause of many cases of ulnar-sided wrist pain that that were previously unknown or misdiagnosed.

The newly defined split tear of the UT ligament is a common source of ulnar-sided wrist pain in which the ligament remains attached to the bone on both ends and is split open lengthwise. The joint is stable, and the MRI is usually interpreted as normal, contributing to diagnostic difficulty.

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Ulnar Fovea Sign

The Mayo team is the first to devise a simple, quick manual examination to help identify the source of ulnar-sided wrist pain. Called the "ulnar fovea sign," it elicits exquisite pain in patients who have 2 kinds of ulnar-sided wrist injuries: foveal disruption of the distal radioulnar ligaments and UT ligament injuries.

Suturing the lengthwise tear has proved to be a durable repair, allowing patients a return to full function of the wrist, with no reports of reinjury.

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The split tear was discovered when the Mayo team performed the ulnar fovea test on a patient while the joint was viewed arthroscopically. This revealed that the source of the pain was elicited from the exact spot where the physician was applying pressure. On clearing blood vessel matter from the area, what had initially looked like a normal ligament was, in fact, split open lengthwise, and the physician was actually viewing the inside of the ligament. Repeated performance of the ulnar fovea test on subsequent patients, followed by arthroscopic examination, demonstrated that a large majority of those with a positive ulnar fovea sign and stable joints had UT split tears.

Table with traits of 2 types of UT ligament injuries.

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Restoring Full Function

The Mayo team devised a relatively easy arthroscopic surgical treatment that can restore full, painfree function and improve quality of life for decades for these patients, most of whom are less than 35 years old. Arthroscopically guided surgery repairs the split by suturing the ligament together. After 6 weeks in a cast to immobilize the wrist, the patient begins rehabilitation. Follow-up results show the repair has been highly durable and resistant to reinjury. Patients have returned to full strength at work and recreation within a few months after surgery — from sheet metal workers to dairy farmers to golfers and even a Major League Baseball player.