Technique Spotlight : Tips and Tricks for Predicting Which Radial Shaft Fractures Will Be Unstable; Repair Options for the DRUJ/TFCC After Radial Fixation

Indications

Persistent distal radioulnar joint (DRUJ) instability or an irreducible DRUJ after anatomic fixation of a radial shaft fracture requires further evaluation and management. The following scenarios are typically encountered after radial shaft fixation:

• 1.

  Reduced and stable DRUJ

• 2.

  Reduced and DRUJ stable only in specific forearm positions (supination or pronation)

• 3.

  Reduced but unstable DRUJ with concomitant large ulnar styloid fracture

• 4.

  Reduced but unstable DRUJ and intact or small ulnar styloid fracture

• 5.

  Irreducible DRUJ

A reduced and stable DRUJ requires no further surgical management. In cases with an ulnar styloid fracture that involves the base or ulnar fovea with concomitant instability of the DRUJ, fixation of the ulnar styloid fracture is recommended to restore the anatomic insertion of the dorsal and palmar ligaments and stabilize the DRUJ. Techniques for fixation of ulnar styloid fractures are discussed in another chapter. An irreducible DRUJ is uncommon, with several case reports describing this clinical scenario. In these cases, an open reduction of the DRUJ should be performed to remove the interposed structures which most commonly includes the extensor carpi ulnaris (ECU) tendon, but also may include tendons of the extensor digitorum communis (EDC) and extensor digiti minimi (EDM), the dorsal joint capsule, and the fractured ulnar styloid. An unstable and reducible DRUJ in a patient with a small ulnar styloid fracture or an intact ulnar styloid should be treated with cast or splint immobilization. In these cases the DRUJ is typically stable and reduced in particular forearm rotations. For example, if the DRUJ is unstable in forearm pronation or neutral but stable in supination, then the patient is immobilized in supination to maintain a reduced position. A persistently or globally unstable DRUJ that cannot be held reduced with immobilization alone will typically be treated either with rigid immobilization in a position of stability with K-wire fixation of the radius to ulna or triangular fibrocartilage complex (TFCC) repair to bone depending on surgeon preference and perception of how high-grade the soft tissue disruption is. Many techniques have been described to perform a TFCC repair in this setting, including all-inside arthroscopic, arthroscopic-assisted open, or full open repair. Regardless of the technique, it is critical that the repair in the setting of DRUJ instability directly reattaches the TFCC to its insertion on the ulnar fovea. The open transosseous repair of the TFCC to the fovea described here allows for reproducible anatomic reattachment without the need for additional skills in wrist arthroscopy, which have not demonstrated superior outcomes.

Preoperative and Intraoperative Evaluation

The amount of DRUJ translation with loading differs from patient to patient, and thus evaluation of the contralateral wrist should be used for comparison. This examination should be performed prior to beginning the operation. While radiographic parameters are not diagnostic for DRUJ instability, the following findings should raise suspicion for a Galeazzi injury in the presence of an isolated radial shaft fracture and prompt further evaluation of the DRUJ after fixation of the radial shaft: radial shaft fractures within 7.5 cm of the lunate facet, 5 mm of radial shortening, widening of the DRUJ, concomitant ulnar styloid base fractures, and ulnar head dislocation. A preoperative lateral radiograph may show dorsal or ulnar dislocation of the ulnar head, with dorsal dislocation being most common. The direction of the dislocation can guide the surgeon on the potential direction of instability after radial shaft fixation. In full pronation, the dorsal superficial fibers, the dorsal joint capsule, and the deep palmar fibers tighten for stability and prevent dorsal dislocation of the ulna, while the reciprocal occurs in supination. As such, the deep palmar ligament is tested in pronation, and the deep dorsal ligament is tested in supination.