CASE STUDY OF A DISTAL FEMUR TI6Al4V LOCKED COMPRESSION PLATE FAILURE SURFACE INVESTIGATION AND FINITE ELEMENT ANALYSIS

Abstract

In this study, the failure of locking compression plates (LCP) used in the treatment of bone fractures resulting from falls in orthopedic patients at Malatya Training and Research Hospital was investigated. The researchers examined the fracture surface of the failed Ti6Al4V LCP using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) images. The fracture pattern of the plate caused by the fall was replicated in a computer-aided design (CAD) model, obtained through three-dimensional (3D) scanning. Additionally, a CAD model of the femur bone was created using magnetic resonance (MR) images. The assembled images of the replicated fracture and the femur bone were used to simulate the application of locked and unlocked compression screws. Considering the weight-bearing load on a human femur, a linear load of 1200 N and 300 N iliopsoas 300 N abductor 600 N hip contact and 70 N tensor fascia latea walking loads had been applied using finite element analysis (FEA). The researchers analyzed the total deformations, von Mises stress, and principal stresses of the plate. When FEA was conducted with walking and body forces applied, it was observed that the walking forces resulted in a 20% higher von Mises stress and a 22.5% greater total deformation 15% low cycle fatigue compared to the body force. During the analysis with walking forces applied, it was noticed that the maximum von Mises stresses on the LCP and the point where fatigue initiation began coincided with the fracture site of the LCP in the patient’s body. However, this observation was in contrast to the analysis with body loads applied.