The purpose of this study is to determine the surgical and clinical outcomes of patients receiving total knee replacement with the same implant using two different types of cutting guides during surgery:

1. Standard knee cutting guides;
2. MRI generated patient specific custom cutting guides.

Both types of cutting guides used in this study are registered with the U.S. Food and Drug Administration (FDA) and are routinely used for knee replacement surgery. However, it is unknown if one type of cutting guide has risks or benefits over the other.

Inclusion Criteria:

• Age 18 - 75
• Diagnosis of osteoarthritis of the knee and qualify for surgery, as indicated by one of the following:
• Painful and disabled knee joint resulting from osteoarthritis where one or more compartments are involved;
• Correction of varus or valgus.
• Willing to participate and return for follow-up study visits.

Exclusion Criteria:

• Infection
• Sepsis
• Osteomyelitis
• Uncooperative patient or patient with neurologic disorders who is incapable of following directions
• Osteoporosis
• Metabolic disorders which may impair bone formation
• Osteomalacia
• Distant foci of infections which may spread to the implant site
• Rapid joint destruction
• Marked bone loss or bone resorption apparent on roentgenogram
• Vascular insufficiency
• Muscular atrophy
• Neuromuscular disease
• Incomplete or deficient soft tissue surrounding the knee
• Previous osteotomy
• Diagnosis of rheumatoid arthritis
• Previous patella fracture or surgery
• Previous healed tibia or femur fractures
• Previous joint replacement surgery
• Cannot have an MRI
• Patients receiving single-stage bilateral total knee arthroplasty (TKA)