Triathlon PKR Study in Japan

Inclusion criteria

• Patient requires a primary unicompartmental knee replacement.
• Patient is between 20 years old to 80 years old.
• Patient is diagnosed as osteoarthritis, rheumatoid arthritis, traumatic arthritis or avascular necrosis.
• Patient can walk independently at least 10m.
• Patient has signed the Institutional Review Board (IRB) approved, study specific informed patient consent form.
• Patient is willing and able to comply with post-operative scheduled clinical and radiographic evaluations and rehabilitation.

Exclusion criteria

• Patient requires a revision.
• Patient is pregnant.
• Patient has lateral osteoarthritis.
• Patient has less than 10°of flexion contracture and greater than 90°of flexion.
• Patient's preoperative mechanical alignment is less than 10° of varus and 15° of valgus.
• Patient has had high tibial osteotomy, femoral osteotomy and/or joint fusion.
• Patient has a neuromuscular or neurosensory deficiency that would limit the ability to assess the performance of the device.
• Patient has a systemic or metabolic disorder leading to progressive bone deterioration.
• Patient is immunologically suppressed or receiving steroids (>30 days) in excess of normal physiological requirements.
• Patient has a deformity which will require the use of wedges or augments.
• Patient has an active or suspected latent infection in or about the knee joint.
• Patient who is inappropriate for participating in the study by the judgment of the investigator.