Spatial deformations of osteosynthesis systems. Message 2. Experimental results

Test procedure and a device for the spatial loading of full-scale bone specimens with fractures and fixation means and simultaneous measurement of mutual displacements arising in the fracture region due to the load are presented. The device allows us to apply longitudinal, transverse bending and rotational one-time and long-term cyclic loads to the specimen, simulating the action of loads when walking. The measurement of displacements was carried out by digitally photographing the fracture areas followed by computer image processing. The test results of the “tibia with simulated fracture - fixation plate” systems under spatial loading by three external forces are presented, which cause compression, bending and torsion. As a result of the tests, the values of mutual displacements and the angles of mutual rotation of parts of the fracture were measured. Comparison of test and calculation results using the relationships described in Message 1 shows the suitability of the method, which allows us to quickly and reliably assess the level of displacements in bone fractures under the spatial loading.