Using the Medial and Lateral Humeral Lines as an Adjunct to Intraoperative Elbow Arthrography to Guide Intraoperative Reduction and Fixation of Distal Humerus Physeal Separations Reduces the Incidence of Postoperative Cubitus Varus.

BACKGROUND: Distal humerus physeal separations are rare pediatric elbow fractures that are often misdiagnosed and difficult to treat. Adequate reduction is often technically challenging and up to 71% of children develop postoperative cubitus varus. We propose using the medial and lateral humeral lines as an adjunct to elbow arthrography in order to guide intraoperative fixation of distal humerus physeal separations to reduce the incidence of postoperative cubitus varus.

METHODS: From 2009 to 2014, all pediatric patients under the age of 3 diagnosed with a distal humerus physeal separation and treated surgically at our institution were included for analysis. Two senior pediatric orthopaedic surgeons separately reviewed the preoperative, intraoperative, and postoperative images of all patients and measured the position of the ulnar axis relative to the medial and lateral humeral lines. The medial and lateral humeral shafts were defined as parallel lines drawn along the medial and lateral humeral diaphysis. Adequate reduction was defined by reduction of the ulnar axis within the boundaries of the medial and lateral humeral lines. Patients were assessed at latest follow-up for cubitus varus and any other surgical complications.

RESULTS: Thirteen patients fulfilled the inclusion criteria and were on average 1.70 years old, ranging from 0.62 to 3 years old. Intraoperatively and immediately postoperatively, all 13 patients (100%) were noted to have adequate reduction of the ulnar axis within the boundaries medial and lateral humeral lines. None of the patients required intraoperative arthrography (0%). At the date of latest follow-up, 12 patients (92.3%) had no angular deformities compared with the contralateral limb and 1 patient (7.7%) had developed cubitus varus. No surgical complications were noted (0%).

CONCLUSION: Intraoperative reduction of the ulnar axis within the boundaries of the medial and lateral humeral lines is associated with a lower incidence of postoperative cubitus varus in the treatment of distal humerus physeal separations in children.

LEVEL OF EVIDENCE: Level IV.