Survivorship of the Press Fit Condylar (P.F.C.) Sigma Fixed Bearing Knee With a Cobalt Chrome Tibial Tray

Inclusion Criteria: * Subjects who have given voluntary written informed consent to participate in this study * Subjects for whom primary total knee replacement is indicated due to degenerative joint disease, including rheumatoid arthritis, osteoarthritis, avascular necrosis, and post traumatic arthritis, which is causing pain, deformity, or limitation of function uncontrolled by medical treatment. * Subjects who, in the opinion of the Investigator, are able to understand this study, co-operate with the investigational procedures and are willing to return to the hospital for all scheduled post-operative follow ups. * Male or Female subjects who are skeletally mature and for whom an appropriate size of device is available * The following subjects are not considered eligible and must not be recruited to the investigation Exclusion Criteria: * Subjects scheduled for revision total knee arthroplasty, or who have had previous surgery to their knee except menisectomy, arthroscopy or synovectomy. * Subjects aged over 80 Years * Subjects experiencing any condition that may, in the opinion of the investigator, interfere with the total knee replacements survival or outcome (e.g. Pagets disease, Charcots disease, severe osteoporosis etc). * Subjects who have evidence of active infections, which may spread, to other areas of the body (e.g. osteomyelitis, pyrogenic infection of the knee joint, overt infection etc) * Subjects who are currently participating in any other clinical investigation of a device or pharmaceutical. * Subjects having non-contained defects in the tibia or femur necessitating bone graft. * Subjects with psychosocial disorders that would limit rehabilitation * Subjects with a known history of poor compliance to medical treatment * Subjects who are known drug or alcohol abusers. * Other contraindications for the use of the P.F.C. ® S fixed bearing knee system as listed in the package insert. * Women who are pregnant * Subjects who are currently involved in any injury litigation claims