Effect of intraoperative Baumann's angle and cubitus varus deformity after humeral supracondylar fracture of children

【Objective】To explore the correlation between cubitus varus deformity after children humeral supracondylar fracture and Baumann's angle in the closed reduction and percutaneous pinning fixation for supracondylar fractures of the humerus in children. 【Methods】Sixty-eight children (male 39, female 28, mean age of 7.2 years) with displaced supracondylar fractures of the humerus had been treated with closed reduction and percutaneous pinning fixation.Under radiographic supervision, three -dimensional displacement of fractures was corrected by closed reduction. The percutaneous Kirschner wire pinning were applied only if the radiographs demonstrated that Baumann's angle on the injured elbow, which had been compared with the normal one. And Baumann's angle on the injured elbow had been examined during the long-term follow-up, also which had been compared with the normal side. 【Results】All of them had been followed up for 36.1 months (ranged from 11 to 49 months). There was one case with ulnar nerve palsy associated with the pinning. There were no Volkmann's contracture in this group. X-ray examinations had revealed an average 73.4 degrees of Baumann's angle on the injured elbow and 72.5 on uninjured side. An average 7.8 degrees of the carrying angle on the injured elbow and 9.4 on uninjured side were also demonstrated by radiography. Three patients developed slight cubitus varus deformity. The results grade according to Flynn criteria were excellent, good, mild and poor. The cases had been divided into four group basing on the Baumann's angle on the injured elbow during after operation, The cases with Baumann's angle on the injured elbow no more the 2 degree was belonged to group A (n=42); The cases with Baumann′s angle more the 2 degree and no more the 4 degree was belonged to group B (n=14); The cases with Baumann's angle more the 4 degree was belonged to group C (n=5). The results grade in the group A were excellent in 26 cases, good in 14, mild in 2 and poor in 0 out of 42 cases, The rate of excellent and good was 95.24%; The results grade in the group B was excellent in 8 cases, good in 4, mild in 1 and poor in 1 out of 14 cases, The rate of excellent and good was 85.71%; excellent in 0 cases, good in 1, mild in 2 and poor in 2 out of 5 cases in the group C according to Flynn criteria, The rate of excellent and good was 20.00%. The difference of the rate of excellent and good had not statistical significant between the group A and the group B (χ2=1.4359, P 0.05); The difference of the rate of excellent and good had statistical significant between the group A and the group C (χ2=22.7121, P 0.05); The difference of the rate of both excellent and good had statistical significant between the group B and the group C (χ2= 7.3634, P 0.05). 【Conclusions】The satisfactory results can be gained in children with displaced supracondylar fractures of the humerus by restoration of the normal Baunann angle and percutaneous pinning fixation.