Medial joint space widening of the ankle in displaced Tillaux and Triplane fractures in children.

OBJECTIVES: Tillaux and Triplane fractures occur in children predominantly from external rotation mechanism. We hypothesized that in displaced fractures, the talus would shift laterally along with the distal fibula and the distal tibial epiphyseal fragment increasing the medial joint space.

DESIGN: Consecutive cases evaluated retrospectively.

SETTING: Level I and Level II centers.

PATIENTS: Twenty-two skeletally immature patients with 14 displaced Triplane fractures and eight displaced Tillaux fractures were evaluated for medial joint space widening.

INTERVENTION: Measurement of fracture displacement and medial joint space widening before and after intervention.

RESULTS: Thirteen Triplane and six Tillaux fractures (86%) showed medial space widening of 1 to 9 mm and equal to the amount of fracture displacement. Reduction of the fracture reduced the medial space to normal. There were no known complications.

CONCLUSIONS: Medial space widening of the ankle may be a sign of ankle fracture displacement. Anatomic reduction of the fracture reduces the medial space and may improve the results in Tillaux and Triplane fractures.