Abstract
Objective To evaluate, through a biomechanical assay, the maximum load, energy, and displacement
necessary for the occurrence of fractures in synthetic models of femurs after the
removal of cannulated screws and the performance of a reinforcement technique with
polymethylmethacrylate (PMMA) in different combined positions.
Methods In total, 25 synthetic bones were used, and they were divided into 4 groups: the
control group (CG), with 10 models without perforation, and the test groups (A, B
and C), with 5 models each. The test groups were fixed with cannulated screws using
the Asnis technique, and they had the synthesis removed, and two of the holes formed
by the reinforcement technique with PMMA were filled. The biomechanical analysis was
performed simulating a fall on the large trochanter using a servo-hydraulic machine.
Results All specimens of the CG and of groups A, B and C presented basal-cervical fracture
of the femoral neck, except for a single model in group B, which presented a longitudinal
fracture. An average of 5.4 mL of PMMA were used to reinforce the groups with filling.
According to the analysis of variance (ANOVA) and the Tukey multiple comparison test,
at the level of 5%, we observed that the CG presented significant differences in relation
to groups A and C in the following parameters: maximum load, energy up to the fracture,
and displacement.
Conclusion We observed that groups A and C, when compared to the CG, showed significant differences
in the observation of displacement, maximum load, and energy until the fracture.
Keywords hip fractures - femoral fractures - osteoporosis - polymethylmethacrylate
