Finite Element Analysis on Dislocation Torque and Contact Stress of a Novel Acetabular Cup Liner Defect When Prosthetic Impingement Occurs

This article concerns the mechanical effects of variously directed a defect in an acetabular liner. Six defect liners with 2.5 mm wear depth were analyzed using the finite element method. The results thus obtained demonstrated that a liner defect with a position at the opposite hemisphere of acetabular cup to the femoral head that was attached to the part of the original area of the liner, the dislocation torque value was similar to the originally designed value. The liner defect at opposite side to the femoral head cause a dislocation torque that was similar to the designed value. In contrast, a liner defect causes a higher torque. The two sizes 24 and 36 mm of femoral heads had maximum stresses in the liner defect with a position at angle of elevation of 90°, with the lowest dislocation torques.