To collect information about implant performance and patient clinical outcomes in patients undergoing primary total knee arthroplasty with the LinkSymphoKnee total knee replacement system with ultra-congruent tibial bearing surface.

The study will collect outcomes data on up to 600 patients from up to 3 sites using a legally marketed device according to its labeled intended use.

The study will collect:

1. KOOS-JR
2. Knee Society Score (KSS), 2011
3. PROMIS Global Health
4. PROMIS Physical Function
5. PROMIS Pain Interference
6. Surgery Satisfaction
7. Forgotten Joint Score
8. Radiographic findings
9. Revisions.

Radiographic evaluations will be done through postoperative year 2. Other outcomes will be evaluated up to postoperative year 5.

Inclusion Criteria:

• 18 years or older, and skeletally mature; and
• Undergoing a primary TKA for one or both knees using the cemented LinkSymphoKnee knee system as part of the surgeon's standard of care.
• Able to read and understand English (because patient-reported outcome questionnaires are not validated for all potential other languages).

Exclusion Criteria:

• 80 years of age or older,
• Women who are pregnant at the time of surgery,
• History of joint sepsis,
• Bone defect that requires grafting,
• Previous history of bone disease (e.g., severe osteoporosis or osteomalacia) which in the surgeon's opinion is severe enough to compromise device fixation,
• Systemic conditions affecting bone density (e.g., inflammatory arthritis or renal disease) which in the surgeon's opinion are severe enough to compromise device fixation,
• A poorly functioning contralateral total knee replacement or a contralateral revision regardless of function.

Patients seeking primary total knee arthroplasty from the participating surgeon investigators