To determine how the LCS mobile bearing knee system works within the Asian Population.

The objective of this clinical evaluation is to compile a profile of the performance of the LCS Mobile bearing total knee system in normal clinical practice within the Asian Population. Performance will be assessed using specific surgeon and patient based outcome scores.

Total subject enrolled 505; 6 subjects did not receive device. Total subjects received device 499.

Among those who received devices, 391 subjects unilateral and 108 bilateral, therefore, total 607 knees in the study

Inclusion Criteria:

• Administrative - the patient is able to understand the evaluation, is able to give consent and will comply with the postoperative follow up regime.
• Diagnosis - idiopathic osteoarthritis, rheumatoid arthritis, post traumatic arthritis or any other pathology that in the opinion of the clinical investigator requires a primary total knee arthroplasty.
• Implant suitability - patients who in the opinion of the Clinical Investigator are considered suitable for treatment with a mobile bearing knee system (the LCS Classic or Universal).
• Bilateral patients - simultaneous bilateral patients are included. Staged bilateral patients are included if the second procedure is performed within the one-year recruitment period. Staged bilateral patients where the second procedure is performed outside of the one-year recruitment period will only be included if the second procedure is performed within 6 months of the end of the one-year recruitment period.
• Age - the upper age limit is set at 75 years and expected to live through the 5 years study period.vi. Ethnic Origin - patients must be Asian in ethnic origin
• Unicondylar / High Tibial Osteotomy (HTO) conversion - patients that are being converted from a unicondylar / HTO procedure are included providing the reason for conversion is due to progression of the disease process affecting the other condyle. Patients that are converted and have evidence of infection / aseptic loosening / loss of bone stock are excluded.

Exclusion Criteria:

• Patients with a known history of poor compliance to medical treatment.
• Patients that require revision surgery
• Patients with gross ligamentous insufficiency.
• Patients with a severe valgus deformity (15 degrees or greater)
• Patients with a severe varus deformity (20 degrees or greater)
• Patients with a fixed flexion contracture (30 degrees or greater)
• Patients over the age of 75 years.