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Journal of Long-Term Effects of Medical Implants
SJR: 0.332 SNIP: 0.491 CiteScore™: 0.89

ISSN Print: 1050-6934
ISSN Online: 1940-4379

Journal of Long-Term Effects of Medical Implants

DOI: 10.1615/JLongTermEffMedImplants.2013008440
pages 275-283

A Study on Polyethylene Stresses in Mobile-Bearing and Fixed-Bearing Total Knee Arthroplasty (TKA) using Explicit Finite Element Analysis

Gunti Ranga Srinivas
Center for Product Design and Manufacturing, Indian Institute of Science, Bangalore, India
Anindya Deb
Center for Product Design and Manufacturing, Indian Institute of Science, Bangalore, India
Malhar N. Kumar
HOSMAT Hospital, Bangalore, India

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.