title: A study on polyethylene stresses in mobile-bearing and fixed-bearing total knee arthroplasty (TKA) using explicit finite element analysis.
abstract: Mobile-bearing total knee arthroplasty designs were thought to be associated with lesser stresses on the polyethylene (PE) insert as compared to fixed-bearing designs. The wear rate of the PE liner was felt to be less in the mobile-bearing knees due to the decrease in the stresses. However, a reevaluation of the biomechanics of the mobile-bearing design is necessary due to the recent clinical reports on the long-term outcome of mobile-bearing knees which have not demonstrated any significant benefit in terms of implant survival and polyethylene wear rate. In this explicit finite element analysis of mobile-bearing and fixed-bearing knee designs using LS-DYNA, no significant differences have been found in the maximal stresses in the superior (articulating) surface of the PE insert in mobile- and fixed-bearing designs. On the inferior surface of the PE insert, the peak stresses were nearly 30% higher in the mobile-bearing compared with the fixed-bearing design. Thus, contrary to earlier expectations, mobile-bearing designs may be associated with higher overall PE stresses and wear than the fixed-bearing designs. Further research is necessary to minimize the wear rate of the PE insert in mobile-bearing total knee arthroplasty.
authors.affiliation: Center for Product Design and Manufacturing, Indian Institute of Science, Bangalore, India.
authors.forename: Gunti Ranga
authors.initials: GR
authors.lastname: Srinivas
authors.affiliation: Center for Product Design and Manufacturing, Indian Institute of Science, Bangalore, India.
authors.forename: Anindya
authors.initials: A
authors.lastname: Deb
authors.affiliation: HOSMAT Hospital, Bangalore, India.
authors.forename: Malhar N
authors.initials: MN
authors.lastname: Kumar
mesh_terms: D019645:Arthroplasty, Replacement, Knee; D020342:Finite Element Analysis; D006801:Humans; D007595:Joint Prosthesis; D008954:Models, Biological; D020959:Polyethylene; D011474:Prosthesis Design; D013314:Stress, Mechanical
chemical_list: D020959:Polyethylene