Mechanical Analysis after Proximal Femoral Reinforcement with Polymethylmethacrylate in Alternated Double Holes^*

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 techniquewith PMMAwere 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 femoralneck, except for a singlemodel in groupB,which presenteda longitudinal fracture. An average of 5.4mL of PMMAwere used to reinforce the groupswith filling. According to the analysis of variance (ANOVA) and the Tukey multiple comparison test, at the level of 5%,weobservedthat theCGpresented significant differences inrelation to groupsAandCin 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