The LCS Complete Cementless Knee by DePuy Synthes is a rotating platform knee replacement with a good clinical track record and good survival rates.

The cementless ATTUNE Cruciate Sacrificing (CS) Rotating Platform Knee by DePuy Synthes has been designed to provide better range of motion and address the unstable feeling some patients experience during everyday activities, such as stair descent and bending. It is expected that the cementless ATTUNE Rotating Platform Knee will have regulatory approval early 2016. Patient inclusion will start after regular approval has been obtained.

The objective of this study is to accurately assess and compare migration, clinical and radiological outcome and patient reported outcomes (PROMS) of two TKR prostheses: the Cementless ATTUNE Rotating Platform Cruciate Sacrificing Knee System and the LCS Complete Cementless Cruciate Sacrificing Knee System (rotating platform design), both by DePuy Synthes, Warsaw, Indiana, USA. In this single-blind, randomized non-inferiority trial, 32 patients with the ATTUNE Knee System and 32 patients with LCS Knee System will be included.

The study population will consist of patients with symptomatic osteoarthritis of the knee scheduled for TKR surgery at the Department of Orthopaedics, Spaarne Gasthuis, Hoofddorp, The Netherlands. Annually 300 TKA procedures are performed in this department, of which about 95% is Osteo Arthritis (OA). The investigator anticipates that inclusion can be accomplished within a 1 year period and that the total study duration is 3 years.

Main study parameters/endpoints are:

• Migration, measured by means of RSA.
• Patient Reported Outcome Measures by means of questionnaires.

Inclusion Criteria:

• Patient is diagnosed with osteoarthritis and requiring primary knee arthroplasty
• All consecutive patients ("usual care") are included to prevent selection bias in the migration analysis.
• Patient is capable of giving informed consent and expressing a willingness to comply with this study

Exclusion Criteria:

The patient has an a-priori risk for a posterior-stabilized total knee arthroplasty.

• Status after patellectomy
• In case flexion is less than 90 degrees
• The patient is unable or unwilling to sign the Informed Consent specific to this study
• The patient does not understand the Dutch or English language good enough to participate
• Patients indicated for revision arthroplasty
• Patient is diagnosed with rheumatoid arthritis
• When there are not enough markers visible in the baseline RSA photograph and it will not improve by placing the patient in another position, the patient will be excluded from the study (secondary exclusion criteria).