A retrospective study was conducted on 60 patients (53 females, seven males with a mean age of 68 years and 5 months) who underwent a total knee replacement using a mobile bearing. The diagnosis was primary osteoarthritis in 57 cases and rheumatoid arthritis in three cases. None of the patients underwent a bilateral procedure, thus 60 implants (33 all cementless, three all cemented, 24 with only the tibial component cemented) were considered. Three different groups were identified: Group 1: first 20 total knee arthroplasties with menisci. Group 2: first 20 total knee arthroplasties with rotating platform. Group 3: first 20 total knee arthroplasties with AP glide platform. Clinical and radiological results at the final follow up, although different in time among the three groups, have shown no revision due to mechanical or septic reasons, and no signs of impending failure.