TALAR NECK FRACTURES - ANATOMIC CONSIDERATIONS FOR POSTERIOR SCREW APPLICATION

The bony window available for posterior screw placement in the talus a nd the morphology of the talar neck were studied in 50 dry tall, In ad dition, 12 cadaver specimens were used to study the posterolateral app roach. The bony window was bounded medially by the lateral tubercle of the posterior process of the talus, laterally by the fibular facet, s uperiorly by the trochlear articular surface, and inferiorly by the po sterior calcaneal facet. The average vertical thickness at 2-mm increm ents was recorded across the talar neck to define the bony mass availa ble for screw insertion. The smallest thickness of the talar neck was at a point 2 mm medial to the lateral border. The thickness progressiv ely increased in a medial direction. The superior talar neck surface w as found to have an average width of 18.4 +/- 1.6 mm. The angle formed between the superior and lateral surfaces of the talar neck averaged 29.3 degrees, which would account for the better delineation of the la teral border of the neck under fluoroscopy of the talus with the foot in pronation. The diameter of the screw in relation to the window heig ht should be considered.