Summary A radiocarpal dislocation (RCD) is the total loss of contact between the carpus and the radius. Diagnosis is confirmed by orthogonal radiographs of the wrist. Treatment is usually internal fixation of the fractured bones, radiocarpal pinning and repair of the radiocarpal ligaments. Epidemiology Incidence 0.2% of injuries to the wrist annually Demographics male > females dorsal dislocation > volar dislocation Risk factors high-energy trauma Etiology Pathophysiology mechanism of injury high energy shear or rotational force to a hyperextended and pronated wrist often due to falls from height and motor vehicle accidents Associated conditions orthopaedic conditions open fractures distal radius fractures radial styloid avulsion fractures attachment of the radioscaphocapitate (RSC) ligament volar lunate facet fractures attachment of the short radiolunate ligament ulnar styloid fracture carpal bone fractures (scaphoid, lunate and trapezium) medial nerve injury > ulnar nerve injury irreducible DRUJ with soft tissue interposition intercarpal injury (scapholunate or lunotriquetral dissociation) Anatomy Osseous distal radius articular surface is biconcave and triangular with the radial styloid forming apex of triangle sigmoid notch forms the base and articulates with head of the ulna dorsal surface of distal radius is convex and serves as floor of the dorsal extensor compartments Ligamentous radiocarpal ligaments, capsule, and the scaphoid and lunate fossa of the distal radius provide stability to the radiocarpal joint short radiolunate ligament is the primary soft-tissue restraint against volar translation of the carpus short radiolunate ligament attaches to the volar lunate facet of the disal radius radioscaphocapitate ligament (RSC) provides restraint against ulnar translation of the carpus RSC ligament attaches to the radial styloid ulnolunate and ulnotriquitral ligaments originate on the volar side of the TFCC (which inserts into base of ulnar styloid) Classification Moneim Classification Type 1 Radiocarpal fracture-dislocation without associated intercarpal dissociation Type 2 Radiocarpal fracture-dislocation with an associated intercarpal dissociation Dumontier Classification Group 1 Radiocarpal fracture-dislocation that is purely ligamentous or involves only a small cortical avulsion fracture off the radius Group 2 Radiocarpal fracture-dislocation associated with a large radial styloid fracture fragment (involving at least one-third of the scaphoid fossa) Presentation History high energy trauma to the wrist Symptoms common symptoms pain and swelling of the wrist numbness and tingling Physical exam inspection radiocarpal deformity based on direction of dislocation (volar or dorsal) ecchymosis & swelling pale and cold hand motion document flexion-extension and pronation-supination crepitus should be noted neurovascular median nerve injuries > ulnar nerve injuries radial and ulnar artery injury is common due to the deformity causing arterial occulsion Imaging Radiographs recommended views PA view of the wrist radiolunate alignment normally two-thirds of the lunate articulates with distal radius in complete radiocarpal disruption, carpus translates ulnarly intercarpal widening evaluate for scapholunate or lunotriquetral dissociation break in the Gilula arcs the radiocarpal, proximal midcarpal, distal midcarpal arcs should be colinear lateral view of the wrist dorsal or volar radiocarpal wrist dislocation loss of colinearity of the lunate with the articular surface of the radius "tear-drop view" 10 degree proximal view on a lateral evaluate for lunate facet fracture CT indications to evaluate articular surface in cases of severe comminution and articular depression MRI indications to evaluate for the integrity of the scapholunate and lunotriquetral Differential Lunate Dislocation (Perilunate dissociation) Distal radius fracture Treatment Nonoperative closed reduction and cast immobilization indications not medically stable for surgery stable radiocarpal joint after closed reduction outcomes historically satisfactory outcomes for purely ligamentous injuries Operative open reduction, internal fixation, radiocarpal pinning and ligament repair indications irreducible radiocarpal dislocation unstable radiocarpal joint after reduction outcomes good outcomes can be achieved with concentric reduction of the radiocarpal joint, treatment of intercarpal injuries and sound repair of the osseousligamentous injuries Techniques Closed reduction and cast immobilization technique longitudinal axial traction of the digits casting for up to 6 weeks to allow ligamentous scarring Open reduction, internal fixation, radiocarpal pinning and ligament repair approach volar approach to distal radius dorsal approach to distal radius technique provisional radiocarpal joint reduction three-column fixation radial column (radial styloid) K-wire, compression screw, or plate fixation (dorsal, volar, or radial) of radial styloid soft tissue or possible suture anchor repair if ligamentous, comminuted, or fragment too small for fracture fixation intermediate column (lunate facet) screw or tension band wire loop fixation of lunate facet soft tissue or possible suture anchor repair if ligamentous, comminuted or too small for fracture fixation short radiolunate and radioscaphocapitate ligament repair ulnar column (controversial) indicated for DRUJ injury or persistent instability following after fixation of radial and intermediate column screw or tension band wiring of ulnar styloid fracture, or ligament repair DRUJ closed or open reduction, percutaneous pinning in mid-supination decompression of neurovascular structures addition of external fixation, radiolunar pin x 4-6 weeks for unstable injuries after fixation can use a dorsal spanning bridge plate instead for additional fixation Complications Acute carpal tunnel syndrome risk factors delay in treatment treatment carpal tunnel release Stiffness incidence 30-40% of total arc of wrist flexion/extension risk factors prolonged immobilization treatment manipulation under anesthesia hardware removal Post-traumatic arthritis risk factors non-anatomic reduction of articular surface Chronic radiocarpal instability Late intercarpal disruption risk factors occult injury to the intercarpal ligaments Prognosis With early treatment and appropriate management, good outcomes can be expected.