Re-dislocation following open reduction for developmental dysplasia of the hip.

We have reviewed 17 patients (18 hips) who required repeat open reduction for recurrent or persistent dislocation after a previous attempt at open reduction for developmental dysplasia of the hip (DDH). The mean follow-up was 5.5 (3-15) years. At the review, five patients were limping and had limited hip motion but no pain. Six hips were classified as Severin class III or more, and avascular necrosis was evident in 11. We suggest that technical failure is usually the cause for re-dislocation in unilateral cases, as we discovered at repeat open reduction in five of six patients with unilateral dislocation. The biological behaviour of bilateral dislocations may in some way be different since in nine of 11 patients with bilateral dislocations, no obvious cause could be attributed. The outcome is usually poor.