Scorpio® Cruciate Retaining (CR) Outcomes Study

Inclusion Criteria: 1. The subject is a male or non-pregnant female between the ages of 21-80. 2. The subject requires a primary cemented total knee replacement. 3. The subject has a diagnosis of osteoarthritis (OA), traumatic arthritis (TA), or avascular necrosis (AVN). 4. The subject has intact collateral ligaments. 5. The subject has signed the IRB approved, study specific Informed Patient Consent Form. 6. The subject is willing and able to comply with postoperative scheduled clinical and radiographic evaluations and rehabilitation. Exclusion Criteria: 1. Patient has inflammatory arthritis. 2. The subject is morbidly obese, \>60% over ideal body weight for frame and height. 3. The subject has a history of total or unicompartmental reconstruction of the affected joint. 4. Patient has had a high tibial osteotomy or femoral osteotomy. 5. The subject has a neuromuscular or neurosensory deficiency, which would limit the ability to assess the performance of the device. 6. The subject has a systemic or metabolic disorder leading to progressive bone deterioration. 7. The subject is immunologically suppressed, or receiving steroids in excess of normal physiological requirements. 8. The subject's bone stock is compromised by disease or infection which cannot provide adequate support and/or fixation to the prosthesis. 9. The subject has had a knee fusion to the affected joint. 10. The subject has an active or suspected latent infection in or about the knee joint. 11. The subject is a prisoner. 12. The subject is pregnant.