The protocol will define the clinical study for Ortho Development's Balanced Knee® System (BKS) for subsequent review and approval by an Institutional Review Board (IRB).This clinical study will compare the clinical outcomes of BKS to currently marketed devices.

The rationale is based on the potential effectiveness of the BKS to:

• Return patient to normal activities or increase mobility by restoring knee function.
• Provide stability to enhance rehabilitation without external support.
• Eliminate or reduce knee pain.
• Assess the clinical efficacy after total knee replacement.
• Determine implant survivorship and viability.
• Evaluate patient function and satisfaction.

Inclusion Criteria:

• Loss of joint configuration and joint function.
• Osteoarthritis of the knee joint.
• Rheumatoid arthritis of the knee joint.
• Post-traumatic arthritis of the knee joint.
• Moderate valgus, varus, or flexion deformities.

Exclusion Criteria:

• Any patient not experiencing a compromised quality of life by loss of joint function and/or joint configuration, or pain from arthritis disease.
• Any patient whose knee cannot be returned to normal function and normal stability through reconstructive procedures, including ligamentous balancing.
• Active infection in or near the knee joint, fever and/or local inflammation signs, and elevation of sedimentation rate unexplained by other diseases should not be treated unless preoperative infection is ruled out.
• Distant foci of infection, such as genitourinary, pulmonary, skin (chronic lesions or ulcerations), and other sites, which may result in hematogenous spread to the implant site.
• Rapid joint destruction or bone absorption apparent on roentgenograms.
• Neuromuscular disorders in which the potentially adverse effects on prosthesis function are not outweighed by the benefits gained by the patient from usage of the prosthesis.
• Mental disorders which would compromise essential patient post-operative care.
• A painless, stable arthrodesis in a functional position.
• Allergic reactions to implant materials, and/or tissue reactions to the products of corrosion or wear.
• Skeletal immaturity.
• Any patient who is unwilling or unable to comply with post-operative instructions or clinical study requirements.