Irreducible Volar DRUJ Dislocation with Distal Radius Fracture Dislocation

Abstract

Background  Volar dislocations of the distal radioulnar joint (DRUJ) are rare and often missed during initial evaluation. Chronic dislocations and disability can occur when DRUJ dislocations are unrecognized and not reduced. DRUJ dislocations often occur with other wrist injuries, which may complicate reduction. Closed reduction can fail to reduce DRUJ dislocations, in which case open reduction is necessary.

Case Description  This case describes a patient who had a volar dislocation of the DRUJ with an associated dorsal distal radius fracture dislocation. Initial attempts at closed reduction were unsuccessful which prompted surgical intervention. After open reduction and internal fixation of the distal radius fracture dislocation, closed reduction of the DRUJ remained unsuccessful. This prompted an open reduction of the DRUJ. Surgical exposure demonstrated that the extensor carpi ulnaris and the distal radius had prevented closed reduction of the DRUJ. Postoperatively, a splint was placed with the wrist in supination. The patient followed-up at the 2- and 4-month intervals with persistent subluxation. However, the patient also reported minimal pain and the ability to return to work and previous level of activity.

Literature Review  Current literature regarding irreducible volar DRUJ dislocations with distal radius fracture dislocations includes sparse case reports, which are reviewed in this report.

Clinical Relevance  This case illustrates successful treatment for an uncommon volar DRUJ dislocation associated with a dorsal distal radius fracture dislocation and can be utilized to help guide future treatment of similar complex cases.

Though first reports of dislocations of the distal radioulnar joint (DRUJ) trace back to 1777 in an article by Desault, ¹ they are still uncommon injuries that are often missed during initial evaluation in the emergency department. Subtle radiographic changes and nonspecific physical examination findings may delay the diagnosis. ² These dislocations can result in prolonged and substantial disability if not recognized and treated acutely. ³

While DRUJ dislocations most commonly result in dorsal displacement of the ulna from the sigmoid notch, volar displacement has been reported. ⁴ Typically, treatment for DRUJ dislocations is closed reduction under conscious sedation. ² Uncommonly, interposition of tendons or other soft tissue into the empty sigmoid notch results in failure of closed reduction. ³ These irreducible dislocations have been referred to as “complex DRUJ dislocations,” and often require dorsal surgical exposure to evaluate for interposed structures and reduce the dislocation. ²

Common injuries that occur concomitantly with DRUJ dislocations are Galeazzi fractures, Essex-Lopresti injuries, and ulnar styloid fractures. ⁵ In this patient, the DRUJ dislocation occurred with a fracture dislocation of the distal radius. The incidence of distal radius fracture dislocation with DRUJ dislocation is very low. ⁶ Therefore, the literature for such injuries is sparse and treatment is not well established.

The purpose of this report is to describe a case of an irreducible volar dislocation of the DRUJ associated with a distal radius fracture dislocation to improve the understanding of the pathoanatomy and guide the future treatment of this rare but potentially debilitating injury.

Case Report

A 27-year-old man sustained an isolated right upper-extremity injury in a motor vehicle accident. Radiographs demonstrated dorsal fracture dislocation of the radiocarpal joint and DRUJ dislocation with volar displacement of the distal ulna ( Fig. 1 ). Initial median nerve paresthesia resolved after closed reduction in finger traps.

Fig. 1.

Prereduction (A) anteroposterior and (B) lateral radiographs of right distal radius fracture dislocation.

Intraoperatively, an 8-cm longitudinal dorsal wrist incision was made in line with Lister's tubercle and the third metacarpal. Definitive fixation of the distal radius fracture was achieved with a dorsal 8-hole 2.7-mm T-plate (Smith and Nephew Inc, Memphis, Tennessee). Next, manual closed reduction of the DRUJ was attempted with volar to dorsal pressure on the distal ulna in both pronation and supination, but was unsuccessful. Consequently, ulnar dissection was performed using the same dorsal incision and the extensor digiti quinti (EDQ) was identified. The EDQ was retracted ulnarly and the dorsal DRUJ joint capsule was incised. We found the ulna to be volarly dislocated from the sigmoid notch ( Fig. 2 ). An elevator was used to reduce the ulna back into the sigmoid notch ( Fig. 3 ). The DRUJ capsule was then imbricated and repaired with nonabsorbable suture. The patient's wrist was immobilized in supination for 6 weeks ( Fig. 4 ).

Fig. 2.

Intraoperative image of right wrist, with asterisk (*) denoting empty sigmoid notch, and arrow denoting extensor digiti minimi tendon.

Fig. 3.

Intraoperative image of right wrist, with asterisk (*) denoting reduced distal ulna in sigmoid notch after open reduction.

Fig. 4.

( A , B ) Intraoperative radiographs after dorsal plate fixation of right distal radius fracture, and open reduction of distal radial ulnar joint (DRUJ).

At his 4-month postoperative visit, slight DRUJ subluxation persisted; however, the patient returned to work and weight lifting and reported minimal pain ( Fig. 5 ). The patient's range of motion included 10 degrees of wrist flexion, 15 degrees of wrist extension, and 90 degrees of pronation and supination.

Fig. 5.

( A , B ) Four-month postoperative radiographs of right wrist with healed distal radius fracture and evidence of persistent dorsal distal radial ulnar joint (DRUJ) subluxation.

Discussion

DRUJ dislocations are rare and often go undiagnosed in the emergency department. A study by Rainey et al showed that over 50% of DRUJ dislocations reported in literature were initially missed during assessment. ⁷ This injury can result in chronic instability if not diagnosed and reduced acutely. ³ It is important to have a high clinical suspicion to identify the often subtle radiographic findings that are needed to diagnose DRUJ dislocations.

The range of motion of the DRUJ and the shallow nature of the sigmoid notch make this joint intrinsically unstable. ⁸ Most of this joint's stability is due to the surrounding soft tissue stabilizers, specifically the triangular fibrocartilage complex (TFCC). ⁸ Describing DRUJ dislocations as volar or dorsal implies the direction of displacement of the ulna in relation to the joint. The majority of DRUJ dislocations cause dorsal ulnar displacement. ⁴ However, this report illustrates a case of a volar DRUJ dislocation. Due to the rarity of such an injury, the specific mechanism for volar dislocations is unknown, though some literature suggests that hypersupination is the cause. ³

On physical examination, inspection of the wrist is unlikely to confirm an acute volar DRUJ dislocation due to overlying soft tissue edema. However, there may be a void dorsally where the distal ulna is not subcutaneously visible or palpable. Physical examination will also reveal an inability to pronate the wrist. Radiographic evaluation should include a precise posteroanterior view of the wrist, because misalignment during radiography can cause false negative results. ⁴ In a volar dislocation, there will be increased overlap between the radius and the ulna, likely due to the pronator quadratus pulling on the distal ulna. ⁴ However, slight supination or pronation during radiography can prevent this overlap. ⁴ When a well-aligned lateral radiograph is used, physicians should be able to visualize volar subluxation of the ulna on the radius.

Another unique aspect of this case is the concomitant dorsal fracture dislocation of the distal radius. Though there are sparse literary reports of distal radius injuries occurring with DRUJ dislocations, the authors are unaware of a previous report of dorsal displacement of a distal radius fracture with a concomitant volar DRUJ dislocation.

Current literature contains various case reports that address why closed reduction may be unsuccessful. ⁴ The most commonly reported cause of “complex DRUJ dislocations” is that the extensor carpi ulnaris (ECU) becomes wrapped around the radial border of the ulna, thus preventing an ulnar reduction into the sigmoid notch. ⁴ Other case reports have suggested that the EDQ tendon, flexor pollicis longus tendon, median nerve, or fragments of an injured TFCC are at fault for complex DRUJ dislocations. ⁴ Another suggested mechanism of irreducibility is the compressive pull of the pronator quadratus. ⁴ Identifying and addressing potential soft tissue interposition is of primary importance during an open reduction. This case was rare in that both the ECU tendon wrapping around the distal ulna, and the distal radius itself, blocked reduction.

It is not uncommon for wrist injuries to result in chronic subluxation of the DRUJ. ⁹ Current literature shows that such instability typically occurs as a result of two distinct scenarios: (1) distal radius fracture that causes deficiency of the sigmoid notch, or (2) injury to the TFCC. ⁹ Treatment in these circumstances may include osteotomy to address the sigmoid notch deficiency or reconstruction of the radioulnar ligaments. ¹⁰ Although our patient continued to have recurrent subluxation of the DRUJ, he was able to return to work and sports with minimal discomfort.

In conclusion, DRUJ dislocations are often challenging to identify. It is important for orthopaedic surgeons to have a high clinical suspicion for such injuries to prevent a missed diagnosis. If closed reduction is unsuccessful, it is important to recognize that soft tissue interposition or a bony impediment may be preventing reduction of the DRUJ. Distal radius fracture dislocations are typically managed surgically. In cases where both injuries occur, this report suggests that fixation of the radius and open reduction of the DRUJ may be necessary.