Wrist Dislocation



Wrist Dislocation


Brooks Ficke

Nileshkumar M. Chaudhari



INTRODUCTION



  • Definition



    • Dislocation of the radiocarpal joint, with or without



      • Radial styloid fracture


      • Dorsal or volar rim avulsion fractures


    • In the category of carpal instability nondissociative


    • This topic does not include articular shear fractures (“Barton” variants), perilunate dislocations, or instability related to distal radius malunion or rheumatoid arthritis.


  • Pathoanatomy



    • Proximal carpal row linked to distal radius by the volar (radioscaphocapitate [RSC], short radiolunate [SRL], long radiolunate[LRL]) and dorsal (dorsal radiocarpal [DRC]) extrinsic wrist ligaments


    • Radiocarpal dislocation requires either near-global ligament disruption or a fracture that disrupts the stability of the osseous insertion of the ligaments.



      • Volar ligaments are typically avulsed from their origin on the distal radius.



        • One report of avulsion distally from the carpal insertions1


      • If a radial styloid fracture is greater than one-third the width of the scaphoid fossa, the RSC and LRL origins usually remain attached to the fractured fragment.2


      • DRC and capsule may avulse small fragments from the dorsal distal radius.


    • Role of extrinsic wrist ligaments



      • Palmar structures provide majority of restraint against dorsal (61%) and volar (48%) translation of the carpus.3


      • SRL is the primary stabilizer against volar translation.4


      • RSC is primary stabilizer against ulnar translation,4,5 but alone is unable to prevent ulnar translation. RSC/LRL together can resist ulnar translation.6



    • Dorsal intercalated segment instability may predispose to dislocation.7,8,9


    • Associated injuries



      • Intercarpal ligament injury


      • Ulnar styloid fracture


      • Distal radioulnar joint (DRUJ) disruption


    • Secondary ulnar translation



      • Distal radius osteology (inclination, volar tilt) creates a tendency for ulnar and palmar translation, which is normally restrained by radiocarpal ligaments.6


      • Typically develops after wrist immobilization has been discontinued


      • Associated with radiocarpal arthritis and limited range of motion2


  • Mechanism of injury



    • Typically high-energy injuries


    • Axial load on hyperextended wrist, with aspects of shearing and rotation10,11



      • Additional pronation and torsion can lead to DRUJ disruption.2,12


      • The radial-based extrinsic ligaments (RSC, SRL, LRL), typically torn during radiocarpal dislocation, tighten with and resist pronation, suggesting that forceful pronation is a part of the injury mechanism.2


  • Epidemiology



    • Most frequent in young active men13


    • Direction of dislocation



      • Dorsal more common, volar quite rare (only 24 reported in literature)14



        • Ulnar extremely rare15,16


    • Pure ligamentous dislocation without any fractures is uncommon


    • Open injuries are rare, but have high (70%) incidence of neurovascular injury17


EVALUATION

May 7, 2019 | Posted by in ORTHOPEDIC | Comments Off on Wrist Dislocation
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