A patient sustained bilateral sacroiliac dislocation in which the proximal part of the sacrum was displaced 10 cm anteriorly and 6 cm inferiorly into the pelvis. Stabilisation was initially obtained with an external fixator. Operation was carried out later: reduction was achieved by overhead skeletal traction using sublaminar wires; two screws were inserted through each sacroiliac joint and the two fragments of the sacrum were wired in place.