BIOMECHANICS OF BONE BLOCK GRAFT MODELS OF DIFFERENT GEOMETRY

OBJECTIVE: To evaluate the mechanical behavior of different geometry bone block grafts in wooden models. METHODS: Constructs with rectangular (G1) and trapezoidal (G2) profile “grafts”, fixed with 3.5 mm 8-hole dynamic compression plates were submitted to non-destructive bending, with the load applied alternately on the same surface as that of the plate fixation (upper) and on the opposite surface (lower), and torsion tests. A 50 N maximum load for bending and a 5° maximum deformation for torsion were considered. Rigidity (N/mm) was recorded for the former and torque (N.m) was recorded for the latter. RESULTS: Rigidity was consistently higher in G2 than in G1, but not significantly so for all comparisons. The exception was for the load applied on the same surface of plate fixation, significantly higher in G1 than in G2. Torque was higher in G1, but not significantly so. CONCLUSION: The two different-profile “grafts” present a similar mechanical behavior and can be indistinctly used in clinical practice. Level of evidence V, specialist's opinion based on basic studies.