13.1 Introduction

Radiocarpal fracture-dislocations are complex injuries characterized by dislocation of the radiocarpal joint (▶Fig. 13.1). It is important to differentiate these from a Barton or reverse Barton (dorsal) fracture (▶Fig. 13.2). Barton fracture involves a shear fracture of the articular surface of distal radius with the fractured fragment attached to the carpus. In addition, the displaced fragment forms a substantial part of the distal radius articular surface. In contrast, radiocarpal fracture-dislocation is a high-energy injury with disruption of the radiocarpal ligaments. It is typically associated with a small cortical rim and/or radial styloid fracture (▶Fig. 13.1). According to the Association for Osteosynthesis (AO) classification, partial articular distal radius fractures are classified as type B. B2.1 fractures involve the dorsal rim of the distal radius. In B2.2, fracture of the dorsal rim is associated with fracture of the radial styloid as well. In B2.3 fractures, the fracture of the dorsal rim is associated with a radial styloid fracture as well, with greater instability than in B2.2 fractures and radiocarpal dislocation.

Radiocarpal fracture-dislocations are rare injuries and their real prevalence is disputed, ranging from 0.2 to 20%. ^{1 , 2} This wide variation in prevalence is likely because of lack of strict definition and grouping radiocarpal dislocations with other injuries including a reverse Barton fracture. In addition, a very distal, severely displaced intra-articular distal radius fracture may resemble a radiocarpal dislocation (▶Fig. 13.3). Dislocation can be dorsal or volar; however, dorsal injuries are more common. ³ These are high-energy injuries primarily seen in younger males in early 30s. ^{3 , 4 , 5} Associated fractures and dislocations, open injuries, tendon ruptures, and neurovascular injuries have all been reported. ^{3 , 6 , 7} The exact mechanism of injury is unclear. It has been postulated to involve a rotational force that is consistent with the high incidence of associated distal radioulnar joint (DRUJ) injuries. ^{3 , 5}

Dumontier et al ³ proposed a classification system dividing these injuries into two groups. Type 1 radiocarpal dislocations are primarily ligamentous injuries. They have a small (less than one-third of width of scaphoid fossa) or absent radial styloid fragment. These dislocations are very rare and accounted for 7/27 cases described in this series. The authors suggested that in this group all volar radiocarpal ligaments are torn and posteriorly the ligamentous injury most often presented as a capsuloperiosteal avulsion. Ligamentous injuries make type 1 injuries globally unstable. Type 2 radiocarpal dislocations are associated with fractures of the radial styloid that involves more than one-third of the width of scaphoid fossa. This fracture usually includes all of the scaphoid fossa and may continue to the dorsal margin of distal radius. The volar radiocarpal ligaments are believed to be attached to the radial styloid fragment and posteriorly there is capsuloperiosteal avulsion. The authors recommended repair of the volar ligamentous structures for type 1 injuries and a dorsal approach with fixation of the radial styloid fragment for type 2 injuries.

A dorsal approach is also recommended for dorsal shear fractures (reverse Barton) and articular surface reconstruction (▶Fig. 13.2). Lozano-Calderón et al ⁸ described 20 patients with dorsal shear fractures associated with radiocarpal subluxation or dislocation. The authors found that these fractures involved dorsal shear fragments associated with: (1) central impaction; (2) impaction of majority of distal radius articular surface; (3) radiocarpal dislocations with rupture of the radiolunate ligaments or fracture of the volar portion of the lunate facet where radiolunate ligaments originate. The authors recommended dorsal approach to buttress the dorsal shear fractures and reconstruct the articular surface for associated central impaction. A combined volar approach was recommended for volar ligamentous repair or fixation of small volar avulsion fracture in radiocarpal dislocations with dorsal shear fractures.

13.2 Indications

Operative management is recommended because of the high energy and unstable nature of these injuries. A thorough history and physical examination should be performed to identify any associated neurovascular injuries. Since most of the radiocarpal dislocations are dorsal with a fracture of the radial styloid and fracture of dorsal cortical rim, a dorsal approach is preferred. Similarly, a dorsal approach is utilized for dorsal shear fractures (reverse Barton) and articular surface reconstruction. These fractures may be accompanied by avulsion of the ulnar styloid and/or disruption of the DRUJ. If there is gross instability after fixation of the radial fracture, it is recommended that the ulnar styloid and/or triangular fibrocartilage complex (TFCC) is reattached. If there is any sign of median nerve injury, it should be decompressed using an additional palmar approach. Every patient should also be assessed for associated carpal injuries.