To evaluate the clinical significance of Baumann’s angle in the closed reduction and percutaneous pinning fixation for supracondylar fractures of the humerus in children.Methods There were 97 children (male 59,female 38,mean age of 6.8 years) with displaced supracondylar fracrtures of the humerus were treated in this hospital.Under fluoroscopy guidance,three-dimensional displacement of fractures was corrected by closed reduction.The percutaneous Kirschner wire pinning was applied only if the radiographs demonstrated that Baumann’s angle was less than 4 degree compared to that on the normal side.All of them were followed up for 34.5 months (range,12 to 48 months).Results There was one case with ulnar nerve palsy associated with the pinning.There were no Volkmann’s contracture in this group.X-ray examinations revealed an average 73.7 degrees of Baumann angle on the injured and 72.8 on uninjured side.An average 7.6 degrees of the carrying angle on the injured and 9.7 on uninjured side were also demonstrated by radiography.Five patients developed slight cubitus varus deformity.The result according to Flynn criteria were excellent in 85 patients (87.6%),good in 12 patients (12.4%).Conclusion The satisfactory results can be gained in children with displaced supracondylar fractures of the humerus by restoration of the normal Baumann angle and percutaneous pinning fixation.18 refs,2 figs. To evaluate the clinical significance of Baumann’s angle in the closed reduction and percutaneous pinning fixation for supracondylar fractures of the humerus in children. Methods There were 97 children (male 59, female 38, mean age of 6.8 years) with displaced supracondylar fracrtures of the humerus were treated in this hospital. Unders fluoroscopy guidance, three-dimensional displacement of fractures was corrected by closed reduction. The percutaneous Kirschner wire pinning was applied only if the radiographs demonstrated that Baumann’s angle was less than 4 degree compared to that on the normal side. All of them were up for 34.5 months (range, 12 to 48 months). Results There was one case with ulnar nerve palsy associated with the pinning. There were no no Volkmann’s contracture in this group. X-ray examinations revealed an average 73.7 degrees of Baumann angle on the injured and 72.8 on uninjured side. An average of 7.6 degrees of the carrying angle on the injured and 9.7 on uninjured side wer e also demonstrated by radiography.Five patients developed slight cubitus varus deformity.The result according to Flynn criteria were excellent in 85 patients (87.6%), good in 12 patients (12.4%). Conclusion The satisfactory results can be gained in children with displaced supracondylar fractures of the humerus by restoration of the normal Baumann angle and percutaneous pinning fixation.18 refs, 2 figs.