Abstract
AIMS: Implant failure in allograft reconstruction is one of the most common problems after treating a large bone defect for a primary bone tumor. The study aimed to investigate the effect of bone cement augmentation with different configurations of dual locking plates used for femoral allograft fixation. METHODS: Four finite element (FE) models of the femur with a 1-mm bone gap were developed at the midshaft with different configurations of the 10-hole fixation dual locking plate (LP) with and without intramedullary bone cement augmentation. Model 1 was the dual LP at the lateral and medial aspect of the femur. Model 2 was Model 1 with bone cement augmentation. Model 3 was the dual LP at the anterior and lateral aspect of the femur. Finally, Model 4 was Model 3 with bone cement augmentation. All models were tested for stiffness under axial compression as well as torsional, lateral-medial, and anterior-posterior bending. In addition, the FE analyses were validated using biomechanical testing on a cadaveric femur. RESULTS: Model 2 had the greatest axial compression stiffness, followed by Models 1, 4, and 3. Bone cement augmentation in Models 2 and 4 had 3.5% and 2.4% greater axial stiffness than the non-augmentation Models 1 and 3, respectively. In the bone cement augmentation models, Model 2 had 11.9% greater axial compression stiffness than Model 4. CONCLUSION: The effect of bone cement augmentation increases construct stiffness less than the effect of the dual LP configuration. A dual lateral-medial LP with bone cement augmentation provides the strongest fixation of the femur in terms of axial compression and lateral bending stiffness.