This study compares and evaluates differences in patient-reported outcome, survivorship and radiological analysis between patients undergoing total knee arthroplasty with use of either Zimmer Biomet PERSONA Posterior Stabilized (PS) system and Smith&Nephew Journey II Bi-Cruciate Stabilized (BCS) system

The aim of this study is to assess patient-reported outcome, survivorship and radiological analysis in patients after total knee arthroplasty, who will undergo the surgery with the use of either Zimmer Biomet PERSONA Posterior Stabilized (PS) system and Smith&Nephew Journey II Bi-Cruciate Stabilized (BCS) system.

To this study 45 consecutive patients undergoing total knee arthroplasty will be recruited to each group. Study protocol is designed as a prospective, blinded, parallel-group, superiority trial, with balanced randomization [1:1]. All participants will be operated in single clinical orthopedic department, by single high-volume surgeon, who performed more than 3000 total knee arthroplasties in his professional career.

Before the surgery patients will fulfill the author's questionnaire concerning their age, height and body mass, level of activity, WOMAC and KOOS scales.

1-day posteoperatively patients will undergo standard computed tomography examination to assess components placement

Inclusion Criteria:

• Listed for a primary total knee replacement (TKR) at the Orthopaedic and Rehabilitation Department Medical University of Warsaw
• Indication for the TKR is primary osteoarthritis of the knee joint involving one or more compartments
• Aged 18 or over
• Patient willing to provide full informed consent to the trial

Exclusion Criteria:

• Listed for a single-stage bilateral TKR procedure
• Severe symptoms in the contralateral knee so as to require staged bilateral knee replacements within 6 months of the primary procedure
• Fixed flexion deformity of 15 degrees or greater who will require excessive resection of the distal femur
• Clinically assessed uncorrectable varus/valgus deformity of 15 degrees or greater
• Any co-morbidity which, in the opinion of the investigator, is severe enough to present an unacceptable risk to the patient's safety
• Inflammatory arthritis
• Previous septic arthritis in the affected knee joint
• Previous surgery to the collateral ligaments of the affected knee
• Patients on warfarin or novel oral anticoagulants (NOACs)
• Will not be resident in the catchment area for at least 6 months post-surgery
• Undertaking the surgery as a private patient
• Patients who, in the opinion of the clinical staff, do not have capacity to consent
• Patients who are pregnant
• Unable to understand written and spoken Polish

Participant will not be informed which type of prosthesis was used in their particular case.

Outcomes Assessor, who will be not present during surgery, will not be informed which type of prosthesis was used in particular patient.