Review Question - QID 2613

The most likely cause of persistent DRUJ incongruity after anatomic reduction and fixation of the radial shaft fracture of the answers above is interposition of the extensor carpi ulnaris (ECU) tendon. The tendon must be extricated from the joint to permit DRUJ reduction.

Gaeleazzi fracture-dislocations, such as that seen in Figure A, are typically stable once the radial shaft fracture is anatomically reduced. After fixation, the DRUJ is translated in pronation, supination, and in a neutral position to test for stability. A “clunk” during passive motion of the DRUJ is further evidence of gross instability. Gross laxity can be treated by splinting in supination or by pinning the DRUJ. However, ECU tendon interposition has been reported as a possible cause of a persistently irreducible DRUJ. Radiographic findings typically demonstrate a dorsally displaced ulnar head and a widened DRUJ. The interposed tendon must be removed from the joint, often through a separate dorsal approach to permit DRUJ reduction.

Bruckner et al. review the evaluation and management of complex dislocations of the DRUJ. The authors note that these injuries are associated with frequent irreducibility, recurrent subluxation, or soft reduction of the DRUJ secondary to interposed tissue. In their institutional series, four of the 11 cases of Galeazzi fractures were associated with complex DRUJ dislocations, most commonly due to displacement of the ECU tendon volar to the ulna, necessitating open reduction. They cautioned that unobtainable or unconvincing reductions should warrant surgical exploration.

Paley et al. reported two cases of an irreducible DRUJ after radial shaft fracture fixation. The authors describe an empty ECU tendon sulcus on the dorsum of the wrist in both cases. One case was noted and addressed intraoperatively. However, the second case was not identified and this patient went on to endure persistent subluxation and diastasis of the DRUJ, ultimately experiencing a poor result. The authors advocate a separate dorsal exposure to reduce the ECU.

Hanel and Scheid reported a case of entrapment of the ECU in the DRUJ in a skeletal immature 12 year old boy. They noted that intraoperative radiographic analysis was significant for a widened DRUJ and dorsally displaced ulnar head. These authors too advocated a separate dorsal exposure to approach and extricate the ECU tendon.

Incorrect answers
Answer 1: The fracture is anatomically reduced but the DRUJ is incongruent because of an interposed ECU tendon. Revision fixation will not address the DRUJ incongruity.
Answer 2: The type of fixation is not the issue. Revising the fixation to another construct will not address the ECU interposition.
Answer 4: Pronator quadratus interposition has not been described in the setting of irreducible DRUJ dislocations.
Answer 5: Flexor carpi ulnaris tendon interposition has also not been described in the setting of irreducible DRUJ dislocations.