BIOMECHANICAL EVALUATION OF METHODS OF INTERNAL-FIXATION OF THE DISTAL HUMERUS

The best results following fractures of the distal humerus are provide d by anatomic reduction and rigid internal fixation. Plates of two des igns placed in five different fixation configurations were used to det ermine the construct that would maximize rigidity of fixation of the d istal 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 t o medial and medial to lateral bending. With cortical contact, two pla tes when placed medial and lateral or at 90 degrees to each other prov ided equivalent rigidity. However, with a cortical gap, the combinatio n of a specially designed anatomic lateral buttress ''J'' plate and a medial reconstruction plate gave the greatest rigidity (ANOVA, p < 0.0 5). Two-plate constructs do not require placement at 90 degrees to obt ain sufficient rigidity, but do require placement on separate bony pil lars and different surfaces.