Topology Optimization of Patient-Specific Custom-Fit Distal Tibia Plate: A Spiral Distal Tibia Bone Fracture

Abstract

Currently, bone fractures are commonly treated with bone fixation plates that present rigid designs and stiff biometals (e.g., Ti-6Al-4V) that increase the probability of stress shielding happening during bone remodeling by shielding the required stress stimuli for adequate healing. This can lead to medical implant loosening, bone resorption and possible bone refracture. In this paper, an initial custom-fit bone plate is designed to be treated based on the computer tomography imaging of a patient suffering from distal tibia spiral fracture. The initial bone plate was redesigned to reduce the risk of bone being stress shielded. Topology optimization were implemented to redesign the bone plates by minimizing the strain energy and reducing the total plate’s volume in three different cases (25%, 50% and 75%). A bone-plate construct was assembled and examined using finite element analysis considering load conditions of the patient’s gait and the tibia bone being loaded with 10% of the bodyweight. The bone stresses were evaluated in order to compare the topology optimized plates with the initial design. The findings show that with higher volume, load transfer reduction increases in the fractured area and reduces the risk of stress shielding. Topology optimization is a viable approach for building custom-fit distal tibia plates for spiral distal tibia fracture.

Keywords

• finite element analysis
• long bone fracture
• medical imaging
• metal bone plates
• stress shielding
• topology optimization