Physica KR Fluoroscopy Study

Inclusion Criteria: 1. Patientsoperated in The Royal Bournemouth Hospital NHS Foundation Trust and who has received a Physica KR implant 2. Patients achieving a ROM ≥ 100° at 6 week follow-up in the Physica KR clinical trial (K-06 Study protocol 30/10/2013 v 1.0); 3. Patients affected by primary or secondary OA before surgery; 4. Patients with an appropriate intial fixation and stability of the knee prosthesis; 5. Patients with undamaged and functional collateral and posterior cruciate ligaments (no ligamentous imbalance or pain); 6. Patients who understand the requirements of the study and are willing and able to comply with activities required for fluoroscopic examination; 7. Patients who have signed the Ethics Committee approved study-specific Informed Consent Form. Exclusion Criteria: 1. Patients with a ROM \< 100° at 6-week follow-up in Physica KR clinical trial (K-06- Study protocol 30/10/2013 v 1.0); 2. Patients affected by rheumatoid arthritis; 3. Patients with malalignment or axial malrotation of the knee prosthesis; 4. Patients who had or have planned a surgery on their uninvolved knee within a year; 5. Muscular insufficiency or absence of muscoligamentous supporting structures required for adequate soft tissue balance; 6. Patients who have significant neurological or musculoskeletal disorders or disease that may adversely affect gait and compromise functional recovery and evaluation; 7. Patients who have neuromuscular or neurosensory deficit which would limit the ability to assess the performance of the device; 8. Any psychiatric illness that would prevent comprehension of the details and nature of the study; 9. Participation in any experimental drug/device study within the 6 months prior to the preoperative visit, excluding the Physica KR clinical trial (K-06 Study protocol 30/10/2013 v 1.0); 10. Female patients who are pregnant, nursing, or planning a pregnancy.