1. A simple test more sensitive than Ortolani's for the diagnosis of instability of the hip in the new-born is described. It takes only a few seconds to perform and can be quickly taught to doctors, nurses and midwives.
2. About one infant in sixty is born with instability of one or both hips. Over 60 per cent of these recover in the first week of life, and 88 per cent in the first two months. The remaining 12 per cent are true congenital dislocations and persist unless treated, giving an incidence of 1·55 per thousand.
3. Treatment with the type of splint described begun within the first week is simple and effective, and gives a hip clinically normal long before the child begins to walk.
4. The concept of a pre-dislocation phase should be abandoned.