A discussion on the causes of children distal humerus fractures leading to cubitus varus

ZHANG Tian-jiu; YU Song; YANG Xiao-hong

doi:10.3969/j.issn.2095-252X.2015.06.011

Abstract：Objective To explore the causes and mechanism of children distal humerus fractures leading to cubitus varus and to provide a clinical reference for surgical correction.Methods From January 2009 to February 2014, 65 children with cubitus varus were adopted, whose clinical data were retrospectively studied. There were 51 males and 14 females, whose average age was 7.5 years old ( range: 4-14 years ). All of the children had a clear history of distal humerus fractures, including 31 cases of supracondylar humeral fractures, 2 cases of humeral lateral condyle fractures, 3 cases of humeral medial condyle fractures, 3 cases of separation of the entire distal humeral epiphysis and 26 cases of unclear diagnosis. The anteroposterior ( AP ) and lateral X-ray iflms of the ipsilateral elbow were observed in all the patients, which were compared with the AP and lateral X-ray iflms of the contralateral elbow or normal elbow. The residual radiographic signs of fracture traces and the development of distal humeral epiphysis were observed. The cubitus varus angle was measured, and the size and shape of the humeral medial condyle and lateral condyle, the olecranon fossa and ulnohumeral joint morphology, changes of the trochlea of the humerus, anteversion of the humerus head and development of the epiphyseal plate were observed. A type of cubitus varus caused by malunion and the other type of cubitus varus caused by imbalance of distal humeral epiphysis growth were compared, and the causes and the mechanism of the formation of cubitus varus were analyzed.Results Cubitus varus was caused by fracture malunion in 58 cases ( 89.2% ), including 31 cases of supracondylar humeral fractures, 2 cases of humeral lateral condyle fractures and 2 cases of separation of the entire distal humeral epiphysis. Cubitus varus was caused by imbalance of distal humeral epiphysis growth in 7 cases, including 3 cases of humeral medial condyle fractures and 1 case of separation of the entire distal humeral epiphysis.Conclusions Clinically, most of the children with cubitus varus are caused by malunion of distal humerus fractures, but a few of them develop from imbalance of distal humeral epiphysis growth. For such cases of cubitus varus, the age and elbow growth potential should be considered in the correction operation, so as to correct moderately, improve the treatment outcomes and reduce the postoperative recurrence rate.