Isolated volar dislocation of distal radioulnar joint: rarely occurring, commonly missed

Abstract

IntroductionDistal radioulnar joint dislocations with associated fractures,such as Galeazzi fracture or distal radius fracture, are com-mon injuries. However, isolated dislocation of distal radio-ulnar joint without fracture is rare and is described in termsof the position of the ulna in relation to the radiocarpal joint[1]. Dorsal dislocation is more common than volar disloca-tion [2, 3]. Because of the paucity of this injury, emergencyphysician may easily miss this injury and the deformedwristmay present to the orthopedic surgeon later. Early diagnosis,reduction,andimmobilization restore forearm rotation inthemajority of cases. Failed closed reduction and unstableDRUJ, however, requires surgical stabilization.Case reportA 16-year-old male sustained an injury to his left wrist aftera fall on outstretched hand. He came to our A&E where anemergency physician attended him. His wrist was X-rayed,and considering no bony injuries, a differential of soft tissueinjury was made. A wrist splint was applied and he wasasked to consult an orthopedic surgeon. Two days later, hepresented to our out-patient department.On examination, there was moderate swelling of the wristand marked restriction of movement. Tenderness could beelicited over ulnar styloid and DRUJ region. Careful exam-ination of the previous X-ray was suggestive of minimallydisplaced ulnar styloid fracture in the anteroposterior viewand volar dislocation of DRUJ in the lateral view [Fig. 1].The dislocation was reduced under supraclavicular blockunder an image intensifier. Radioulnar transfixation with a1.8-mm K-wire was done, as the joint was unstable [Fig. 2].Limb was immobilized in an above elbow cast. The fractureof ulnar styloid was minimally displaced and just above thebase. It assumed itsposition after relocation ofulna so it wasnot fixed. The cast as well as the K-wire was removed after6 weeks [Fig. 3]. Gradual physiotherapy regained full func-tion and movements of wrist after 4 weeks. A 1-year follow-up reduced DRUJ, leading to pain-free wrist with full rangeof movements.DiscussionCotton and Brickley [4] were the first to describe this injurypattern in cadaver. Forced hypersupination of the forearmgenerally results in volar dislocation of the ulna. Other