Flexion–extension Cross Pinning of Supracondylar Humeral Fractures in Children: Does It Really Increase Stability and Prevent Ulnar Nerve Injury?

Introduction: Supracondylar fractures of the distal humerus are the most frequent elbow fractures in children, prone to serious complications when treated improperly. There is no consensus in the literature regarding proper configuration of wire pinning. The standard treatment protocol after reduction of a displaced supracondylar fracture in our hospital is insertion of two lateral Kirschner wires in full flexion and insertion of a medial wire in full extension in order to prevent injury of the ulnar nerve. The purpose of this study was to evaluate stability and incidence of ulnar nerve injury of this flexion-extension technique.

Method: From October 2001 to January 2016, we operated on 305 children using the flexion-extension cross-pinning technique. All patients had Gartland type 3 extension type fractures. We reviewed all patient files, including x-rays and neurological status, before and after surgery. Bauman angle was evaluated before and three weeks after surgery.

Results: One patient has ulnar nerve palsy postoperatively; on review of the intraoperative x-rays, the K-wire was inserted significantly below the medial epicondyle. The mean change of the Bauman angle was 2.1° three weeks after surgery and showed no statistical or clinical significance. There were no cubitus varus complications.

Conclusion: Flexion-extension cross-pinning provides excellent mechanical stability and, when done properly, prevents ulnar nerve palsy. Insertion of the medial wire must be done in extension through the medial epicondyle, using fluoroscopic verification of the wire position.