Fluoroscopic Analysis of Total Knee Replacement With a Kinematic Retaining or a Posterior Stabilized Design

Inclusion Criteria: 1. Patients submitted to Total knee arthroplasty (TKA) with Physica KR or PS; 2. Patients with an appropriate initial fixation and stability of the knee prosthesis; 3. Patients achieving a minimum flexion of 100° or a Knee Society Score (KSS) ≥ 65 (fair/good postoperative outcome) at 6-month follow-up; 4. Patients affected by primary or secondary Osteoarthritis (OA) before surgery; 5. Patients who understand the requirements of the study and are willing and able to comply with activities required for fluoroscopic examination; 6. Patients who have signed the Ethics Committee approved study-specific Informed Consent Form. Exclusion Criteria: 1. Patients with misalignment or axial malrotation of the knee prosthesis; 2. Patients not able to achieve a minimum flexion of 100° or with a KSS Knee Score ≤ 65 points at 6-month follow-up; 3. Patients who had or have planned a surgery on their uninvolved knee within a year; 4. Muscular insufficiency or absence of muscololigamentous supporting structures required for adequate soft tissue balance; 5. Patients who have significant neurological or musculoskeletal disorders or disease that may adversely affect gait and compromise functional recovery and evaluation; 6. Patients who have neuromuscular or neurosensory deficit which would limit the ability to assess the performance of the device; 7. Any psychiatric illness that would prevent comprehension of the details and nature of the study; 8. Participation in any experimental drug/device study within the 6 months prior to the screening visit 9. Female patients who are pregnant, nursing, or planning a pregnancy due to x-rays exposition.