Comparative Biomechanical Analysis of Two Olecranon Osteotomy Fixation Techniques

To compare the biomechanical characteristics of olecranon osteotomy fixation using transcortical (TC) or intramedullary (IM) screws.

We sectioned synthetic polyurethane ulnas to simulate a Chevron osteotomy. Osteotomy fixations were performed using TC ( n  = 11) or IM screws ( n  = 11). After the fixation, we assembled the specimens on a positioning device in the testing machine to subject them to a preload of 10 N, followed by 100 loading cycles ranging from 10 to 500 N. At the end of the 100 cycles, we maintained the 500-N load and assessed the opening of the fracture focus (gap) in the osteotomy region. Then, we applied monotonic tensile loading until fixation failure and measured the maximum resistance force, system stiffness, and failure mode.

No group presented failure after the application of load cycles ranging from 10 to 500 N, with no difference in gap values ( p  = 0,9420). The maximum failure force in the IM group was 1.27 times greater than in the TC group ( p  = 0.0459). The stiffness of the 2 systems was similar ( p  = 0,670).

Both techniques were effective alternatives in terms of stability and rigidity. Fixation with IM screws resulted in better load-bearing capacity before failure, suggesting a potential advantage in mechanical strength. The results of the present study may help the interpretation of the clinical implications of the two techniques in investigations on fixation methods for olecranon osteotomy.