Intraoperative stability testing of lateral-entry pin fixation of pediatric supracondylar humeral fractures

The aims of this study were (1) to ascertain prospectively whether rotational instability can be determined intraoperatively and (2) to quantify the incidence of rotational instability after lateral-entry wire fixation in type-3 supracondylar humeral fractures in children according to Wilkins modification of Gartland classification. (Fractures in Children. Vol 3. 4th ed. 1996:669-750). Twenty-one consecutive patients admitted with type-3 supracondylar fractures at the Children's Hospital at Westmead were surgically treated according to a predetermined protocol. After closed fracture reduction, 2 lateral-entry wires were inserted under radiographic control. Stability was then assessed by comparing lateral fluoroscopic images in internal and external rotation. If the fracture remained rotationally unstable, a third lateral-entry wire was inserted, and images were repeated. A medial wire was used only if instability was demonstrated after the insertion of 3 lateral wires. Rotational stability was achieved with 2 lateral-entry wires in 6 cases, 3 lateral-entry wires in 10 cases, and with an additional medial wire in 5 cases. Our results were compared with a control group of patients treated at our hospital before the introduction of this protocol. No patients required a reoperation after the introduction of our protocol as opposed to 6 patients in the control group. On analysis of radiographs, the protocol resulted in significantly less fracture position loss as evidenced by change in Baumann angle (P < 0.05) and lateral rotational percentage (P < 0.05). We conclude that supracondylar fractures that are rotationally stable intraoperatively after wire fixation are unlikely to displace postoperatively. Only a small proportion (26%) of these fractures were rotationally stable with 2 lateral-entry wires.