A retrospective analysis of plate contouring in the tibia using the conventional 4.5 (narrow) dynamic compression plate.

Plate contouring is an essential part of plate osteosynthesis. Its safety and technical ease is dependent on plate factors (material and design) and the complexity of the contouring. Our purpose was to determine the range of plate contouring; estimate the strain on the plate from the radius of curvature in the area of contouring; and determine whether shaped plates had a reduction in their load carrying capacity. A retrospective analysis of 500 radiographed tibias that had undergone osteosynthesis with the conventional dynamic compression plate was conducted to evaluate the radius of curvature and degree of bend in the plates, and to determine whether plates were bent at screw holes. Contouring of the plate to fit the bone was done by the surgeon at the time of application. Postoperative radiographs were evaluated. We found that (a) the shorter the length of plate contoured, the greater the strain; (b) plates were bent at screw holes, and these tended to be the areas of highest strain; (c) the range of plate strain was 0.6-16% (average 1.6%); and (d) plates were bent from 10 to 90 degrees (average 20 degrees).