Total Hip Arthroplasty: Effect of Head Size, Offset Gap, Offset Angle, Trunnion Length and Fixation on Trunnionosis of Hip Implant

Trunnionosis can be defined as the wear of the femoral head-neck contact. This phenomenon is increasingly recognized as a major factor in hip arthroplasty failure. The selection of a highly compatible head has become crucial to reduce the trunnionosis effects in orthopedic surgery. In this study, the biomechanical behavior and wear corrosion of the trunnion of hip implants with 28, 32, 36, 40, and 44 mm head sizes and ±3 mm head offset gap configurations have been investigated using finite element methods. The hip implant configurations were modeled in Autodesk Fusion 360, and the simulations of the static, modal, and dynamic finite element analyses were performed using ANSYS. The effects of different head sizes and offset gap configurations, offset angles, fixation models, and trunnion lengths on wear corrosion are analyzed based on stress, deformation, penetration, sliding distance, frequency vibrational effects, and moment reactions. The results show that the configuration with -3 mm offset, 28 mm head size, 132° offset angle, and type 3 fixation results in higher stability; the -3 mm offset, 28 mm head size, 127° offset angle, and type 2 fixation configuration leads to lower moment reaction.