Investigation of human hip dislocation using 3-D finite human hip model

In Total Hip Arthroplasty (THA), the femoral head is removed and an implant is inserted in the femur. The implant works as a substitute for the femoral head. The purpose of this project is to run simulations to investigate if perforated stem is as strong as or stronger than non-perforated stem. The simulations were performed to investigate on whether lessening the depth of the cement in THA could compromise the success rate of the surgery. Next step, the best implant will be fabricated using a 3-D printer. Based on simulation analysis, implants with higher perforated depths had higher maximum deformations and shear stresses but lower maximum equivalent (von Mises) stresses recorded. For the first case, the relative percentage differences, in cement depth of 74 mm, of the non-perforated, 2 mm, 3 mm, and 4 mm perforated implants; in maximum total deformation were 16.63%, 16.90%, and 16.30%, respectively. Meanwhile, in maximum shear stress, the relative percentage differences were -6.01%, -8.39%, and -7.06%, respectively. In maximum equivalent (von Mises) stress, the relative percentage differences were -0.34%, -1.34%, and -1.42%, respectively. In the second case, the relative percentage differences, in cement depth of 104 mm, of the non-perforated, 2 mm, 3 mm, and 4 mm perforated implants in maximum total deformation were 6.96%, 4.17%, and 7.01%, respectively. In maximum shear stress, the relative percentage differences were 3.64%, 1.01%, and 2.47%. In maximum equivalent (von Mises) stress, the relative percentage differences were -0.34%, -1.34%, and -1.42%. For the third case, the relative percentage differences, in cement depth, of 134 mm of the non-perforated, 2 mm, 3 mm, and 4 mm perforated implants in maximum total deformation were 9.76%, 9.88%, and 10.09%, respectively. In maximum shear stress, the relative percentage differences were 3.61%, 0.98%, and 2.45%. In maximum equivalent (von Mises) stress, the relative percentage differences were -0.34%, -1.34%, and -1.42%. The percentage difference in maximum deformation and maximum shear stress were relatively high especially in maximum shear stress but the opposite was true in maximum equivalent (von Mises) stress. The maximum total deformation and shear stress therefore had influenced greatly on the selection of the best implant. The implant with perforated depths of 3 mm was selected as the best implant and was fabricated using a 3-D printer.