WHICH PRIMARY TOTAL KNEE REPLACEMENT - A REVIEW OF CURRENTLY AVAILABLE TKR IN THE UNITED-KINGDOM

Comparative information on total knee replacements (TKRs) is not readi ly available. With the help of implant manufacturers and distributors, we have compiled a list of TKRs on the market in the UK and summarise d the information about these implants in a table. There are 37 differ ent TKRs, marketed by 14 companies; 54% have been introduced since 199 0. The number of different implants is increasing. At least eight desi gns have undergone major modifications, while many have had minor alte rations. Of the TKRs on the market, 60% are modular. Some 54% of TKRs have no published results in peer-reviewed journals; only one of the f our most widely used prostheses has published survival figures. New an d modified implants are introduced without clinical evidence of their superiority over other available designs. Published results in peer-re viewed journals are currently the best evidence available on the relia bility of an implant. When selecting an implant, surgeons should be aw are if the prosthesis has any such results, the length of the follow-u p, and the survival rates that are achieved. More detailed interpretat ion is difficult because of the different combinations used in modular implants and because of the frequent modification of existing designs . Properly conducted long-term clinical trials should be encouraged as they are the only means of evaluating new designs.