LinkSymphoKnee (LSK) Total Knee Replacement System Study - Ultra-congruent (UC)

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.

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.