A strain recording model: analysis of transverse osteotomy fixation in small bones.

Many current experimental testing procedures are cumbersome when applied to osteotomies of small bones and are complicated by the need for in-depth analyses of data derived from various specimens tested to failure. This strain recording model minimizes these factors. Various forms of internal fixation may be serially tested on the same specimen with this system because constructs are not tested to failure but rather within the elastic range of each specimen. Sophistication in the form of strain recorded as a function of time allows the comparison of various fixation techniques. Fixation techniques applied to a transverse osteotomy and subjected to controlled flexion loading in a single plane have been evaluated. The study demonstrates the superiority of tension bands (wires) placed through holes immediately subjacent to the tension cortex in comparison with wires that fix the components through holes in the neutral longitudinal axis. In addition, for any given time, the strain generated by a single-looped tension band (wire) is greater than that of a figure-of-eight tension band (wire). Both types of tension bands afford superior stability experimentally, compared to conventional crossed Kirschner wire fixation of transverse osteotomies.