[Significance of rotation errors in supracondylar humeral fractures in the child].

To get information about the importance of malrotation for posttraumatic varus or valgus deformity a clinical, radiological and CT follow-up examination of 20 children who were treated for supracondylar fracture from 1983 to 1985 was done. Rotational-displacement was measured on computed tomographical images taken from the region where fracture had happened. On the ap follow-up X-ray from both, the fractured and the other side, and the X-ray which was made after reduction, the medial and lateral colonne were measured from a "special point" in the middle of the shaft of the humerus. The length of the colonnes and their difference were compared. 15 of the 20 patients showed internal malrotation, 1 patient external malrotation and 4 showed no rotational-displacement. In 15 of the 16 patients with malrotation, the rotational-displacement caused a change in the length of the colonnes. Just in one case malrotation caused a minimal deformity of the carrying angle without alteration of the length of the colonnes. 93% of the cases with internal malrotation showed varus deformity. In 3 cases we saw growth disturbance of the epiphyseal plate, but the induced alteration of the length of the colonnes were minimal compared with the changes caused by malrotation.