OPTIMIZATION OF THE ORTHO-SUV FRAME ASSEMBLY FOR CORRECTION OF THE DISTAL FEMUR DEFORMITIES

The aim of the study was to investigate optimal assembly of the computer assisted Ortho-SUV Frame for correction of the distal femur deformities which will provide the maximal bone fragments mutual movements and have the minimal assembly sizes. For it 360 bench tests on 12 model was performed. The dependence of the Ortho-SUV Frame reduction capabilities (translation, angulation, torsion) and distance between supports, places of struts fixation and use of Z-shaped plates for struts fixation was investigated. It is found that in Ortho-SUV assembling to provide the necessary requirements 3/4 ring supports is reasonable. Distal support should be placed at the level VII, proximal at the distance 150–200 mm higher. For fixation of the strut 1 to the proximal support position 2 should be used, for the strut 3 – the place between position 5 and 6, for strut 5 – position 10; for fixation of the strut 2 to the distal support position 4 should be used, for fixation of the strut 4 – position 8, for strut 6 – position 12. Use of the Z-shaped plates in fixation of strut 1 and 5 increases the reduction capabilities on 11.4–25.5% in average. Use of modular transformation of the frame allows decreasing the bulkiness of the frame after deformity correction. Investigated assembly was applied in treatment of 14 patients. In all the cases the aim of Ortho-SUV frame use (deformity correction) was reached.