With regard, for instance, to congenital dislocations at the shoulder-joint, little or nothing was known save what was contained in the writings of Hippocrates, till R.M.Smith and Guerin discussed the lesion in their works.
Among congenital dislocations, those of the hips are most common--in fact, 90 per cent of all.

They are sometimes not recognizable until after the lapse of months and sometimes for years, but their causes--faulty developments of the joint, paralysis, etc .-- are supposed to have existed at birth.

One or both joints may be involved, and according to the amount of involvement the gait is peculiar.

As to the reduction of such a dislocation, the most that can be done is to diminish the deformity and functional disability by traction and palliative measures with apparatus.

The normal structure of the joint does not exist, and therefore the dislocation admits of no reduction.
Congenital dislocations of the shoulder are also seen, owing to faulty development of the glenoid fossa; and at the knee, the leg generally being in extreme hyperextension, the foot sometimes resting on the abdomen.