Longitudinal Split Tears of the Ulnotriquetral Ligament

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A tear of the ulnotriquetral (UT) ligament can be a troubling source of pain for the athlete, especially those participating in racquet and batting sports. The UT ligament originates from the TFCC and ulnar styloid and is typically injured when an axial load is applied to an extended wrist with forearm supination. The diagnosis is based on physical exam, specifically the ulnar fovea sign. The stability of the distal radioulnar joint (DRUJ) differentiates a longitudinal split tear of the UT ligament from a TFCC foveal tear. The utility of radiographic imaging is primarily to rule out other causes of ulnar-sided wrist pain. Once a UT ligament tear has been suspected by history and examination, the diagnosis can be confirmed arthroscopically, and one or two sutures are typically sufficient for repair. Arthroscopic repair leads to excellent results with return to full athletic participation.

Introduction

Wrist pain can be debilitating to an athlete because of apprehension and weakness. The frustration from missed participation is often exacerbated by an examination and radiographic workup that yield no specific diagnosis. A longitudinal split tear of the ulnotriquetral (UT) ligament should be considered in athletes with ulnar-sided wrist pain. Athletes especially at risk for a UT ligament tear are those with repetitive forearm supination or pronation and wrist extension, such as participants in racquet, club, and batting sports. A fall onto an extended wrist can also cause a UT ligament tear.

UT ligament split tears are related to triangular fibrocartilage complex (TFCC) tears by both anatomy and mechanism, but they represent a distinct entity that has characteristic history and physical examination findings. Fortunately, excellent results have been reported for young, active patients who have undergone repair.1 The goal of this article is to discuss the anatomy, diagnosis, and treatment algorithm for longitudinal split tears in the active patient.

Section snippets

Anatomy

Similar to other extrinsic wrist ligaments, the UT ligament is a nondiscrete thickening of the wrist capsule, which consists of longitudinally oriented collagen fibers.2, 3, 4, 5 The UT ligament is one of the primary stabilizers of the ulnar side of the wrist, the other 2 ulnocarpal ligaments being the ulnocapitate and the ulnolunate (UL) ligaments.2, 5 In healthy patients, the UT ligament measures 13.2 ± 3.6 mm in length.6 The UT ligament originates from the TFCC, specifically the palmar

Biomechanics and Injury

Biomechanics of the normal and injured UT ligament continue to be elucidated. Radiographic studies have shown the UT ligament to be longest with wrist extension and radial deviation, consistent with the extension phase of the dart-throwing motion.6, 7, 8 Using length as a surrogate for tension, the UT ligament is believed to be tensioned and at highest risk of injury with wrist radial deviation and extension.1, 6, 8 Additionally, a cadaveric model showed that the tension with the UT ligament

History and Examination

An injury to the UT ligament should be a part of the differential for patients presenting with ulnar-sided wrist pain.9 Athletes in particular may complain of pain with back-hand swings or follow-through or both, motions involving forearm supination and wrist extension. In the largest published series on UT ligament tears, 23 of 36 patients (64%) reported a discrete traumatic event and 4 (11%) reported repetitive trauma. Of these 27 patients, 26 (96%) described an injury mechanism involving

Imaging

Plain films of the wrist cannot be used to diagnose longitudinal split tears of the UT ligament, but they should be routinely obtained to rule out other pathology such as an ulnar styloid fracture or nonunion or ulnar positive variance resulting in ulnocarpal impaction syndrome. Additionally, magnetic resonance imaging (MRI) has not been found to aid in the diagnosis of UT ligament tears (Fig. 3). In a study of 60 wrists (including 20 controls) with noncontrast 3-Tesla MR imaging, 2 blinded

Operative Treatment

Using a standard wrist arthroscopy setup, a diagnostic arthroscopy of the radiocarpal and midcarpal joints is performed to identify any other sources for ulnar-sided wrist pain, such as lunate chondromalacia consistent with ulnocarpal impaction (Fig. 4A) or lunotriquetral ligament injury (Fig. 4B) with special attention given to the integrity of the TFCC.

Using a 4-5 working portal, the TFCC can be evaluated for the so-called trampoline sign where the surgeon depresses the center of the disk

Rehabilitation

Postoperatively, the wrist and the forearm should be immobilized with either a sugar-tong splint or posterior splint extending above the elbow with the forearm in neutral rotation. At the first postoperative visit, the patient is transitioned to a long-arm cast for an additional 4 weeks. At 6-week postoperative, a Munster-type orthosis is fabricated and the patient is instructed on home-based active range-of-motion exercises for the forearm and the wrist. Patients can then wean themselves out

Outcomes

There are no studies reporting the outcomes of nonoperative treatment of UT ligament tears, likely because of the need for arthroscopy to definitively diagnose the condition.1 In the largest series of UT ligament repairs in the literature, patient satisfaction was 89%. Additionally, 90% of the patients denied limitations on their activities.1 Grip strength and range of motion were not significantly changed postoperatively. The postoperative disabilities of the arm, shoulder, and hand score at

Conclusion

A longitudinal split tear of the UT ligament should be part of the differential diagnosis in patients with ulnar-sided wrist pain, especially in athletes who participate in racquet, club, or batting activities. The UT ligament is intimately connected to the TFCC and is at risk of tearing when the wrist is axially loaded with the wrist in extension and radial deviation and the forearm is in supination. The ulnar fovea sign is the most important physical examination finding, and a UT ligament

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