Biomechanical analysis of diversified screw arrangement on 11 holes locking compression plate considering time-varying properties of callus

The 11 holes locking compression plate (LCP) is a type of fixator which is currently used in orthopedic surgeries for fixing fractures of long bones. 8 styles of screw positioning on this plate are possible so each orthopedist may use one of them during operations. The aim of the current study was the analysis of diversified screw arrangement on the mentioned LCP for fixation of medial transverse fracture of tibia considering time- varying properties of bone callus in 16-weeks curing duration. Stress shielding effects were also considered. Finite element method using Mimics 10.01, Solid works 2012 and Abaqus 6.11-1 software have been applied. Modeling of bone was done based on computer tomography (CT) scan of human right tibia and four types of forces have been loaded on intact bone and the same was loaded on fixated fractured ones in 8 treatments of fixation. Stresses in bone, plate and screws, also gap or callus strains and stiffnesses in 5 terms of curing duration in all of the treatments have been investigated and compared together using new defined parameters. Finally the preferred treatment was concluded. Results of this study may be used by orthopedists in applying such a fixator for fixation of tibia and other fractured long bones.