Fixed or mobile-bearing total knee arthroplasty
1 Department of Orthopaedic Surgery, Mackay Memorial Hospital, No. 92, Sec. 2, Chung-San North Road, Taipei 104, Taiwan
2 Institute of Biomedical Engineering, National Yang Ming University, No. 155, Sec 2, Li-Nung Street, Taipei 112, Taiwan
3 School and Graduate Institute of Physical Therapy, College of Medicine, National Taiwan University, 3F, No. 17, Xuzhou Road, Taipei 100, Taiwan
Journal of Orthopaedic Surgery and Research 2007, 2:1 doi:10.1186/1749-799X-2-1Published: 5 January 2007
Fixed and mobile-bearing in total knee arthroplasty are still discussed controversially. In this article, biomechanical and clinical aspects in both fixed and mobile-bearing designs were reviewed. In biomechanical aspect, the mobile-bearing design has proved to provide less tibiofemoral contact stresses under tibiofemoral malalignment conditions. It also provides less wear rate in in-vitro simulator test. Patients with posterior stabilized mobile-bearing knees had more axial tibiofemoral rotation than patients with posterior stabilized fixed-bearing knees during gait as well as in a deep knee-bend activity. However, in clinical aspect, the mid-term or long-term survivorship of mobile-bearing knees has no superiority over that of fixed-bearing knees. The theoretical advantages for mobile-bearing design to provide a long-term durability have not been demonstrated by any outcome studies. Finally, the fixed-bearing design with all-polyethylene tibial component is suggested for relatively inactive, elder people. The mobile-bearing design is suggested for younger or higher-demand patients due to the potential for reduced polyethylene wear and more normal kinematics response after joint replacement. For younger surgeon, the fixed-bearing design is suggested due to less demand for surgical technique. For experienced surgeon, one familiar surgical protocol and instrumentation is suggested rather than implant design, either fixed-bearing or mobile-bearing.