Specific complications of the mobile-bearing total knee prosthesis

Total knee arthroplasty (TKA) is considered as a standard procedure for the treatment of the severe degenerative knee joint. The outcomes of TKA have improved over the last few decades because of a better understanding of design features and surgical techniques. Contemporary tibial component designs in TKA can be subdivided into two groups (fixed or mobile-bearing) on the basis of different fundamental principles. The mobile-bearing knee is designed with better biomechanical concepts than the fixed-bearing knee, in terms of providing congruity and mobility of tibial bearing. It is expected that the mobile-bearing knee could resolve the problems of component wear and component loosening as seen in fixed-bearing knees. However, the long-term durability of mobile-bearing knees has not been extensively proven to have better outcomes than that of fixed-bearing knees. There are some potential clinical complications of mobile-bearing knees that must be addressed. On the basis of our previous clinical experience and a retrieval analysis, this article summarizes five specific complications including (1) early or late dislocation of the mobile-bearing component, (2) failure or dislodging of the meniscal bearing, (3) hemarthrosis associated with a failure of the meniscal-bearing knee, (4) failure of the patellar component, and (5) higher prevalence of osteolysis. Before taking advantage of mobile bearing, we should consider these specific clinical complications, which were not found in the fixed-bearing TKA.