Advantages of Mobile-bearing Total Knee Arthroplasty

Early historical failure of total knee arthroplasty (TKA) was frequently secondary to aseptic loosening, often associated with malalignment, instability, or use of excessively constrained prosthetic components. With the addition of better surgical instrumentation and operative techniques (ligamentous balancing, improved alignment, etc.) and the use of lowerconformity prosthetic devices, loosening rates have been minimized. However, the use of lower-conformity TKA designs resulted in a reduction of polyethylene contact area and premature polyethylene wear, and periprosthetic osteolysis became a predominant mode of TKA failure. The excellent 10–15-year outcomes of TKA has encouraged many surgeons to perform TKA on younger patients. Typically, these subjects have increased activity requirements and longevity expectations approaching three decades or more. To meet the demands of these younger patients, future TKA design must improve functional performance and reduce articular bearing surface wear, while maintaining the excellent long-term fixation typically obtained in properly aligned and balanced TKAs in use today. The purpose of this article is to review factors affecting polyethylene wear following TKA, particularly the design and technical problems of mobile-bearing TKA.