The Reduction Maneuver for Pediatric Extension Type 3 Supracondylar Humerus Fractures

Extension type supracondylar humerus fractures in children commonly displace in two directions: posteromedial and posterolateral. The traditional maneuver to reduce posteromedial displaced fractures utilizes pronation of the forearm, while the maneuver for posterolateral displaced fractures utilizes supination. Traditional teaching suggests that the periosteum is an aid to reduction. The purpose of this study is to take a second look at this periosteal hinge theory and reexamine the maneuver performed when reducing an extension type 3 supracondylar fracture. Sixty-nine consecutive displaced extension type 3 supracondylar fractures were studied. Intraoperative fluoroscopic radiographs were graded as posteromedial, posterolateral, or direct posterior displacement. All fractures were treated with closed reduction and percutaneous pinning. The best maneuver used to align the fracture during surgery was recorded in the operative note. The direction of displacement on radiographs was 32 (46.3%) posteromedial, 31 (45%) posterolateral, and six (8.7%) direct posterior. All of the 32 posteromedial displaced fractures were best aligned when pronation was utilized. All of the 31 posterolaterally displaced fractures were best aligned when supination was utilized. The six direct posteriorly displaced fractures obtained the best alignment in pronation. The current study reaffirms the classic teaching that the direction of displacement of the fracture indicates the site of the intact periosteum. The intact periosteal hinge can be used to obtain fracture reduction.