The majority of these uncommon injuries are caused by a longitudinal blow to the tip of the finger. Typically, hyperextension of the finger causes dorsal, or, rarely, palmar dislocation. In both cases, disruptions of the collateral ligaments and the volar plate will be present. In palmar dislocations, there will be an additional terminal extensor tendon disinsertion.
Diagnosis is based on
the history of the trauma and mechanism of the injury
AP and lateral x-rays are necessary for diagnosis. Be careful to avoid superimposition of other fingers.
In the lateral view, the middle and distal phalanges should be collinear. Any axial malalignment is a clear indication of subluxation.