ABSTRACT
A large number of proximal humerus fractures are being treated with osteosynthesis. However, loss of reduction remains a serious problem and it can cause screw cutout at the humeral joint and reoperation.
According to the interfragmentary strain theory, one should be aware of the balance between a flexible fixation, which stimulates callus formation, and an unstable fixation, leading to implant failure. The main elements that are implicated in this case include physiological loading conditions, support screws configuration, implant material and bone quality. The objective of this research was to detect the influence of the above elements to formulate a positive scene to reduce the risk of failure in the fracture.
A factorial experimental design was used in combination with the use of the finite element method to give rise to data collection.
The results suggested that implant material is the element with the most significant influence and it contributes to stabilizing the fracture fixation, following by the support configuration. The practice of including a medial support with calcar screws on different bone tissue qualities offers a more favorable rigidity than those who do not use them. This affirmation is supported by the results of recently published reports. In addition, the medial support reduces the strain in the bone-plate join. Although these results showed a too moderate evaluation per the use of an isotropic model, they are effective to know the biomechanical elements and their influence to describe a behavior trend and create a basis for future studies. In addition, the computing time decreased considerably.
Keywords
Biomechanics; humeral proximal fracture; locking plate; medial support screws
