[Experimental examinations in plate-prebending--a contribution to the biomechanics of compression osteosynthesis (author's transl)].

The rigid fixation of bone fragments by compression osteosynthesis with plate produces a high degree of resistance against bending forces, and over the surface friction against rotatory movements. In this way, a uniform distribution of pressure extending over the whole bone section is effected. But by virtue of the asymmetric positioning of the plate on bone-shaft, a torque effect is caused when strain is applied bringing about a distraction of the cortex on the side opposite the plate. Human femoral and tibial specimens would be osteomatized and then stabilized with AO plate adapted to conform to the surface of the bones, under a tension of 70 and 140 kp. With narrow plates having a inferior rigidity there is a greater distraction than is the cause with the wide plates. To compensate against the torque effect, the plates would be prebent. Two measuring methods would be investigate by which the correlation between prestraining and prebending could be determined. To achieve a constant distribution of pressure the narrow plates would have to be prebent to a greater degree than the wide ones, and the DC plates more than the standard plates.