Translunate fracture with associated perilunate injury: 3 case reports with introduction of the translunate arc concept.

We report 3 cases of translunate fractures with associated perilunate dislocations (or subluxation). We believe the translunate injury reflects a higher-velocity trauma and produces further destabilization of the carpus when compared with the established greater and lesser arc injuries. A modification to Johnson's perilunate injury classification system is proposed: the addition of a translunate arc injury subgroup, which would include all perilunate injuries with translunate fractures.