Uncemented Tritanium Compared With Cemented Metal-backed Tibia Components in Total Knee Replacement

Overview

The optimal method of total knee replacement component fixation to the bone remains a challenge. The use of bone cement is considered the gold standard and is the preferred technique for most surgeons. However, uncemented fixation methods have been developed in an attempt to tackle problems that can be seen when cement is used. The cement-bone interlock can deform and degrade over the years and can lead to aseptic loosening, especially in young and active patients. A loosened prosthesis results in an impaired functioning and painful knee in daily life for which a revision of the prosthesis may be necessary. To prevent aseptic loosening and subsequent revision surgery, new methods of uncemented fixation have been developed. One of these methods is to use a highly porous metal called Tritanium®. It can improve the biologic fixation by resembling the characteristics of trabecular bone. It is expected that this surface aids bone ingrowth and to have similar or even better results concerning early fixation properties and long-term durability compared with cemented fixation. Excellent results using this highly porous Tritanium have been seen in total hip surgery already. This single-blinded, randomized clinical trial will assess clinical and radiological outcomes including Roentgen Stereophotogrammetry (RSA) measurements of a newly approved uncemented Triathlon Tritanium CR total knee prosthesis compared with a standard cemented Triathlon metal-backed CR total knee prosthesis (both by Stryker Orthopaedics). Two arms of each 35 patients will be included. The primary outcome measure will be prosthetic migration after two years of the uncemented Triathlon Tritanium CR Total Knee and the cemented Triathlon CR Total Knee by means of RSA. It is hypothesized that the new uncemented Tritanium prosthesis will perform at least equally good in terms of migration and clinical parameters compared with the standard cemented Triathlon. The secondary outcome measure will be long-term (10-year) survival based on the two-year migration patterns combined with clinical factors and radiographic aspects. In order to identify other clinical parameters besides the fixation of the prosthesis components, clinical scores and radiographic aspects will be correlated with the RSA outcome. The 10-year results will be used to verify the predicted long-term survival results.