Nonlinear Three-Dimensional Finite Element Analysis of Newly Designed Cementless Total Hip Stems

• Published in: Artificial organs Vol. 23; no. 4; pp. 339 - 346
• Main Authors: Ando, Masao, Imura, Shinichi, Omori, Hironori, Okumura, Yasuhiro, Bo, Akihiko, Baba, Hisatoshi
• Format: Journal Article
• Language: English
• Published: Boston, USA Blackwell Science Inc 01.04.1999
• Subjects: Arthroplasty, Replacement, Hip; Cementation; Cementless total hip arthroplasty; Computer Simulation; Female; Femur - physiology; Finite Element Analysis; Fit and fill; Hip Prosthesis; Humans; Middle Aged; Osteoarthritis, Hip - physiopathology; Osteoarthritis, Hip - surgery; Prosthesis Design; Secondary osteoarthritis of hip; Stem design; Stress, Mechanical; Three-dimensional finite element analysis
• ISSN: 0160-564X; 1525-1594
• DOI: 10.1046/j.1525-1594.1999.06214.x

We designed 2 new types of proximally coated stems (the FMS and FMS‐anatomic) based on the endosteal geometry of femora with congenital dislocation or dysplastic hip. The FMS was symmetric while the FMS‐anatomic was asymmetric. We compared the proximal fit and fill to the femoral canal, contact stress, relative motion, and load transfer to the femur of 5 stems (FMS, FMS‐anatomic, Omnifit, Omniflex, and individual stem) using three‐dimensional computer simulation and finite element analysis. The FMS and FMS‐anatomic showed a significantly greater fit and fill than conventional stems. The dispersion of the contact stresses and reduction of relative motions in the proximal area were the best in the FMS‐anatomic compared to other stems with the exception of the individual stem. In addition, the FMS‐anatomic stem transferred most of the load to the proximal femur. Our results suggest that the FMS‐anatomic should provide better biomechanical stability at least in the early postoperative period.