Optimum configuration of cannulated hip screws for the fixation of intracapsular hip fractures: a biomechanical study.

The radiographs of a sample of patients who had canulated hip screw fixation for intracapsular femoral neck fractures were reviewed in our region. There were six different types of configurations used in these fixations which are divided into two groups: (I) triangular configurations, consisting of two parallel screws with a third screw placed either superiorly, inferiorly, anteriorly or posteriorly; and (II) linear configurations with two or three screws in a vertical line. In our study, we tested the relative strength of each configuration in a laboratory setting using synthetic bone models. Statistical analysis, at 5% significance level, using two-way ANOVA and post-hoc test was carried out to test the differences of the results between the configurations.Our results clearly show that the triangular configurations had a higher peak load, higher ultimate load, less displacement and more energy absorption before failure than other configurations.