Biomechanical evaluation of methods of internal fixation of the distal humerus.

The best results following fractures of the distal humerus are provided by anatomic reduction and rigid internal fixation. Plates of two designs placed in five different fixation configurations were used to determine the construct that would maximize rigidity of fixation of the distal humerus. Using a cadaver distal humerus osteotomy, with and then without cortical contact, motion of the distal fragment was measured with respect to the proximal fragment in axial and torsional loading, anterior to posterior and posterior to anterior bending, and lateral to medial and medial to lateral bending. With cortical contact, two plates when placed medial and lateral or at 90 degrees to each other provided equivalent rigidity. However, with a cortical gap, the combination of a specially designed anatomic lateral buttress "J" plate and a medial reconstruction plate gave the greatest rigidity (ANOVA, p < 0.05). Two-plate constructs do not require placement at 90 degrees to obtain sufficient rigidity, but do require placement on separate bony pillars and different surfaces.