A Clinical Trial Study of Knee System in Primary Total Knee Arthroplasty in China

Inclusion Criteria: 1. . The subject is ≥18years old 2. . The Subject must be of Chinese ethnic descent and be willing to return on three occasions for clinical evaluations. 3. . Subject is a suitable candidate for cemented primary TKA using the devices described in this CIP with either resurfaced or non-resurfaced patellae. 4. . Subject must meet all criteria specified in BOTH China Knee stem and P.F.C.® Sigma knee instructions for use (IFU) 5. . Before surgery, subject is willing and able to sign the informed consent form approved by the Institutional Review Board (IRB), Ethics Committee (EC) or Ethical Review Board (ERB). 6. . Subject, in the opinion of the Clinical Investigator, is able to understand this clinical investigation and co-operate with investigational procedures. 7. . Subject must be comfortable with speaking, reading, and understanding questions and providing responses in an available translated language for the patient reported outcomes (PROs) in the CIP. 8. . Subject is receiving a unilateral knee replacement or, if a contralateral knee replacement is anticipated, the surgery must occur within 6 months of the first study knee TKA. The second knee will not be enrolled in the study. Exclusion Criteria: 1. Subject does not provide written voluntary consent to participate in the clinical study. 2. The Subject is a woman who is pregnant or lactating. 3. Subject is anticipated to require a contralateral TKA between 6 months and 1 year. 4. Contralateral knee has already been enrolled in this study. 5. Previous partial knee replacement (unicompartmental, bicompartmental or patellofemoral joint replacement), patellectomy, high tibial osteotomy or primary TKA in affected knee. 6. Subject has a malignant disease, severe condition, alcohol or drug addiction and/or mental disorders that the investigator believes will interfere with the study participation. 7. Subjects with severe osteoporosis, metabolic bone disease, radioactive bone disease or tumor in bone surrounding knee joint that, in the opinion of the investigator, will negatively impact implant fixation and the outcome of the investigation 8. Subject has significant neurological or musculoskeletal disorders or disease that may adversely affect gait or weight bearing (e.g. muscular dystrophy, multiple sclerosis, cerebral infarction, hemiplegia, Charcot disease). 9. Subject is not comfortable with speaking, reading, and understanding questions and providing responses in an available translated language for the PROs in the CIP. 10. Subject has a medical condition with less than 2 years of life expectancy. 11. The Subject has comorbid condition(s) that could limit the Subject's ability to participate in the study, compliance with follow-up requirements or impact the scientific integrity of the study. 12. The Subject is currently participating in another investigational drug or device study. 13. Subject is a prisoner. 14. The Subject has a known allergy to any implant components (metal for example). 15. Hemoglobin \< 11 g/dL 16. Albumin \< 90% normal low limit 17. CRP \> 2 times normal upper limit 18. ESR \> 2 times normal upper limit 19. Subjects who have abnormal coagulation exam results and cannot be corrected by drugs or plasma replacement \-