Dorsal carpometacarpal dislocation of the fifth finger: discussion of diagnosis tend therapy on two cases

Dorsal dislocation of the fifth carpometacarpal joint after injury is rare. Only five cases are reported in the literature. We report on two cases of dorsal dislocation of the fifth carpometacarpal joint after injury and we g ive a review of relatet literature. There are two interesting aspects conce rning diagnostic and therapy of dorsal dislocation of the fifth carpometaca rpal joint. Anteriorposterior and lateral radiographs do not always provide adequate visualisation of th is joint so a dislocation may be misdiagnosed . A radiograph taken with the forearm pronated 45 degrees from the routine anteriorposterior position better shows the dislocation. The adequate thera py consists in closed reduction, Kirsch ner wire fixation and cast immobili sation. A reduction without following Kirschner wire fixation - even in tho se dislocations that were found to be stable after closed reduction - is no t recommended because of the risk of persisting pain after heavy manual wor k. In our two cases an instability of the fifth carpometacarpal joint exsis ted after closed reduction. After Kirschner wire fixation and cast immobili sation for 6 weeks both patients showed 3 months after operative therapy a full range of movement and a powerfull grip without any pain in the fifth c arpometacarpal joint.