This double-blinded randomized control study will use kinematic and kinetic measures to compare an anatomical congruent prosthetic knee design to a standard prosthetic knee design. The patients will be measured pre- and post-operative and compared to a healthy non-osteoarthritis control group.

Inclusion Criteria:

• Informed and written consent.
• Primary knee osteoarthritis in capable men and women.
• Indication for cruciate-retaining total knee arthroplasty.

Exclusion Criteria:

• Patients who do not speak and read Danish.
• Patients who are pregnant or at risk of becoming pregnant during the project.
• Patients with active cancer and/or radiation or chemotherapy.
• Patients who are alcoholics or have some form of abuse that impede information and follow-up.
• Patients with severe psychiatric disease that might complicate compliance with follow-up.
• Patients with surgically implants in the affected leg and/or pace maker.
• Patients with greater thigh circumference then 60 cm.
• Patients cannot perform the described exercises.
• Patients with knee instability due to multiligament injury.
• Patients with conditions that severely compromise their gait other than knee osteoarthritis in the affected knee.
• Patients with severe fracture sequelae or severe malalignment at knee level.
• Patients with osteosynthesised fractures using bone graft at knee level.
• Patients with need of an augmentation and/or stem-elongation.
• Patients with metabolic bone disease.
• Patients with rheumatoid arthritis.