Optimization of the arrangement of ring-spice-rod fixators on the experimental data base during the treatment of tibia nonunion

Abstract

the problem of tibial bone non-unions after fractures is an actual and not finally solvedproblem. The use of ring spoke-rod devices is the leading method of treatment. Improvement of thistechnology is a generally accepted direction to improve the results of treatment. The aim of the work
 was to improve the results of the treatment of non-unions of the lower leg bones based on the im-provement of the fixation technology of ring retainers. In order to fulfill the task of the research, the
 problematic issues of fixation of non-unions of lower leg bones after fractures with spoke-rod ringdevices were studied; the formulated concept of solving the existing shortcomings of the method inthe experiment; clinical applications and analysis of the obtained results. The influence of the spatial
 fixation of the rod in the ring fixator of the spoke-rod type was determined experimentally. The sub-ject of the study was a Sawbones® synthetic bone with a fracture model, which was fixed with a ring
 fixator of the spoke-rod type by 2 models. In our «apparatus-bone» fixation experiment, all the mainparameters of both models (number of rings, spokes, angles of intersection of spokes and fractureplanes) were similar. The difference between the two models was only in the presence or absence of a
 stiffener for fixing the rod. 60 victims met the criteria for inclusion in the study. 31 patients were op-erated on with the use of ring devices with increased rigidity of rod fixation according to the proposed
 method; they formed the main group. 29 patients - the comparison group, the treatment was carriedout according to the generally accepted method using fixation of the rod without a rib of «stiffness».Clinical evaluation of the results was carried out using the anatomic-functional scale of the ModifiedFunctional Evaluation System by Karlstrom-Olerud. The obtained experimental data indicated an
 improvement in the stiffness parameters of the spoke-rod system when using rod fixation with a stiff-ening rib. The greatest effect was obtained during the bending test - the indicator increased from 0.91
 to 1.19 H/mm (by 23.53%). The results of clinical effectiveness obtained by us (good and excellent
 77.8%; unsatisfactory in 2.8%) can be compared with the data of most researchers. Anatomic-func-tional results in the main group with a high probability (95%) exceeded the results in the comparison
 group. Experimental data were confirmed by clinical results. The anatomic-functional results in the
 main group according to the values of the estimated anatomic-functional scale of the Modified Func-tional Evaluation System by Karlstrom-Olerud with a high probability (>95%) exceeded the results
 in the comparison group. Bearing in mind the severity of the lesion, we consider the obtained clinicalresults to be encouraging. Application of the proposed improvements and further investigation oftheir effectiveness should be recommended.