Change of Carrying Angle in Fracture of the Lateral Humeral Condyle in Children: The New Radiologic Carrying Angle Measuring Method

Lee, Jung Yoon; Sohn, Sung Keun; Kim, Keyong Taek; Kim, Sung Soo; Park, Dong Man

Abstract

The lateral condyle fracture of humerus in children is the second most common fracture among the elbow fractures. In dealing with this fracture, we have frequently encountered the various complications due to physeal plate and intraarticular involvement. Change of the carrying angle is one of the common complications, but many authors reported different results about the change of carrying angle. Also, it is too difficult to measure the carrying angle during the early stage of the treatment because of cast immobilization, motion limitation of elbow, and wide variations of radiologic carrying angle according to elbow position changes. We performed this study to find the more stable and predictable new radiologic measuring method about the carrying angle, and then analysed the factors affecting the changes of canying angle of the 23 patients of the lateral condyle fractures of the humerus in children who were treated and followed up more than twelve months at the Department of Orhopaedic Surgery, Dong-A University Hospital from May 1990 to April 1993. The results were as follows. 1. Carrying angles by Beals method showed variable values according to the elbow positions, but A-angles by the new measuring method were relatively stable regardless of the elbow positons. 2. Increase of clinical carrying angle was 3 cases, decrease was 9 cases, and ranges of clinical carrying angle change were from -7 degress to 14 degrees. Increase of A-angle was 7 cases, decrease was 4 cases, and ranges of A-angle change were from -10 degrees to +10 degrees. 3. The change of canying angle showed no correlation with Jacob stage, follow up duration, metaphyseal height and interval between injury and treatment. But the incidence and the amount of carrying angle change were increased according to the increased age at injury(r=0.62, P<0.01). 4. There were statistical significant correlation(r=-0.65, p<0.01) and regression between the change of canying angle and A-angle : Y=-0.99X+0.56(Y:change of clinical canying angle,X; A-angle change), (r2=0.42, P<0.01).