A Finite Element Analysis of Transtrochanteric Curved Varus Osteotomy Combined with Compression Hip Screw System

Background: Complications such as Nonunion, Metal failure and Periprosthetic fracture were found after the TCVO surgery accounting for the mechanical reasons mainly, moreover. There was no any research for simulating TCVO model by using the finite element analysis from the literature. Methods: A TCVO model with 25° fixed with compression hip screw system, which assigned an isotropic heterogeneous material property for the femur was estimated and simulated initial post-operative stage and bone-healing stage, in which the mechanical parameters were compared. Results: (1) The Max displacement in non-friction condition was 9.695 mm. And a strong decrease with the Max displacement of 3.456 mm in condition of bonding for the interfaces. (2) The concentration of von Mises stress on the interfaces were present at the area of lag tunnel with the Max values: 122.0MPa in shaft and 84.20MPa in head, comparing the bone-healing stage, the concentration of von Mises stress in the infero-medial area of contact of the shaft with the Max values: 80.95MPa. (3) The concentration of von Mises stress was both displaced in the junction of osteotomy for the CHS system with the Max von Mises stress values: 1765MPa and 334MPa in two conditions. Conclusions: It was conformed that there was higher instability and fracture risk in the initial post-operative period with more displacement and higher stress in the concentrated point, it was indicated that the load-constrained activities and strong fixation were benefit to decrease the complication and improve the success rate for clinical practice.