[Essential flat foot in the child. Definition, diagnosis and therapeutic indications (author's transl)].

There exists considerable confusion in the definition and classification of essential flat foot in the child. In an attempt to put an end to this confusion, the authors define the radiological characteristics and course of the abnormality. The latter is defined radiologically on lateral films of the foot whilst weight bearing by study of the angle of the calcaneum over the horizontal (Angle C) and by the measurement of the angle of talo-calcaneal divergence (Angle T.C.D.). Three groups may be distinguished on this basis: Group I - of minimal gravity; Group II - which may correct itself spontaneously and is, in general, well tolerated; Group III - which alone requires surgical correction. Treatment is only surgical in severe forms and is based upon the "Horseman" operation, orthopaedic treatment by special soles being rarely indicated.