Stacked 1/3 Tubular Plates for Fixation of Pediatric Forearm Fractures: A Biomechanical Study

Abstract

Introduction. Among operatively treated pediatric forearm fractures, many different fixation constructs are described. The goal of this study is to define the biomechanical properties of a double stacked 1/3 tubular plate construct used by the senior author for some fractures and to review available literature regarding the use of stacked plates.

Methods. Biomechanical testing was performed by 4-point bending of 3 different plate constructs: 1/3 tubular plate, stacked 1/3 tubular plates, and 2.7 mm LC-DCP plate. Five test specimens were evaluated for each of the three plate constructs.  From stress-strain curves, flexural stiffness (N/mm), force to cause plastic deformation (N), and force to cause 10º bend (N) were calculated and compared using standard t-test statistics.

Results. Key outcome parameter means (± SD) for the three plate constructs (1/3 tubular plate, stacked 1/3 tubular plates, and 2.7 mm LC-DCP plate) are reported respectively as follows: flexural stiffness (55.4 ± 3.5 N/mm, 131.7 ± 3.5 N/mm, 113.3 ± 12.1 N/mm), force to cause plastic deformation (113.6 ± 11.0 N, 242.1 ± 13.0 N, 192.2 ± 17.9 N), and force to cause a 10º bend (140.0 ± 8.4 N, 299.4 ± 14.1 N, 265.5 ± 21.2 N).  Mean values of all three measures were significantly larger for the stacked 1/3 tubular plates than for the other plate constructs.

Conclusions. The stacked 1/3 tubular plate construct was biomechanically superior to the other plate constructs. Stacked plating significantly improves stiffness of the fracture fixation construct supporting use of this technique in selected trauma cases.