Design considerations for ceramic resurfaced femoral head: effect of  interface characteristics  on failure mechanisms.
Ceramic hip resurfacing may offer improved wear resistance compared to metallic components. The study is aimed at investigating the effects of stiffer ceramic components on the stress/strain-related failure mechanisms in the resurfaced femur, using three-dimensional finite element models of intact and resurfaced femurs with varying stem–bone interface conditions. Tensile stresses in the cement varied between 1 and 5 MPa. Postoperatively, 20–85% strain shielding was observed inside the resurfaced head. The variability in stem–bone interface condition strongly influenced the stresses and strains generated within the resurfaced femoral head. For full stem–bone contact, high tensile (151–158 MPa) stresses were generated at the cup–stem junction, indicating risk of fracture. Moreover, there was risk of femoral neck fracture due to elevated bone strains (0.60–0.80% strain) in the proximal femoral neck region. Stresses in the ceramic component are reduced if a frictionless gap condition exists at the stem–bone interface. High stresses, coupled with increased strain shielding in the ceramic resurfaced femur, appear to be major concerns regarding its use as an alternative material.
Pal
Bidyut
B
Department of Mechanical Engineering, Indian Institute of Technology, Kharagpur 721 302, West Bengal, India.
Gupta
Sanjay
S
New
Andrew M R
AM
D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation / Q000379:methods; D001696:Biomechanical Phenomena; D001698:Biomedical Engineering; D002516:Ceramics; D019245:Compressive Strength; D003198:Computer Simulation; D017076:Computer-Aided Design; D055119:Elastic Modulus; D019544:Equipment Failure Analysis; D020342:Finite Element Analysis; D006622:Hip Prosthesis; D006801:Humans; D008422:Materials Testing; D011474:Prosthesis Design; D011475:Prosthesis Failure; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength