The Normal Humero-Capitellar Angle in Children ; Baumann Angle and Lateral Humero-Capitellar Angle

In children, the cause of angular deformity after the treatment of distal humeral fracture is mainly not dew to the growth problem but the alignment of initial reduction state. The alignment of reduction status can be measured by numerous methods for anatomical reduction. The Baumann angle and lateral humero-capitellar angle are the most useful radiologic measuring methods for the evaluation of the anatomical configuration of distal humerus. But the determination of the straight line along the capitellar growth plate has some difficulties because the curved rounded capitellar shape may overlap the distal humeral metaphysis. So, 4 types classfication suggested by Williamson et. is used for determination of the line eith easy.

The Baumann angle is a valuable measurement method of distal humerus alignment, but as we know, there is no normal range data in Korean children. We measured the normal Baumann angle and lateral humero-capitellar angle using 112 cases normal elbow X-ray films and analysed its significanses.

The results are as follows:

1) The mean baumann angle is 69.2° with 6.2° standard deviation.

2) The mean lateral humero-capitellar angle is 45.3° with 8.2° standard deviation.

3) The Baumann angle and lateral humero-capitellar angle have no differences between ages, sexes, sidedness and types.

4) The 4 types classification by the shape of the capitellar growth plate is a realtively objective and useful method for the measurement of Baumann angle.

5) The Baumann angle has negative value coefficiency with lateral humero-capitellar angle.