Clinical Outcome and OR Resource Use of Total Knee Arthroplasty Using Patient-Specific or Conventional Instrumentation (TKA PSI)

Inclusion Criteria:

• Painful, disabled knee joint resulting from osteoarthritis requiring primary TKA
• Informed Consent: Patient has signed a "Patient Informed Consent.
• Able and willing to undergo a preoperative MRI scan (for PSI cases) and full-leg, standing radiographs (all cases)
• Able and willing to follow instructions and complete follow-up
• Patient receiving Zimmer NexGen Solutions CR-Flex (including Gender Solutions)

Exclusion Criteria:

• Patient is skeletally immature
• Active Infection (including septic knee, distant infection, or osteomyelitis)
• Severe hip arthrosis
• Neurological disorders (including, but not limited to Parkinson's disease)
• Prior unicompartmental knee arthroplasty, TKA, knee fusion or patellectomy
• Hip or knee ankylosis
• Either rheumatoid or post-traumatic knee arthritis
• Scheduled for simultaneous bilateral TKA
• Indications of intra- and/or extra-articular deformations that would inhibit the use of PSI guides
• Any metal within 150 mm of the joint line for the operative-side knee
• Knee deformities greater than 15 degrees of fixed varus, valgus, or flexion contracture on initial physical examination
• An existing condition that would, in the opinion of the investigator, compromise participation or follow-up in this study
• A female who is pregnant or lactating
• Current involvement in any personal injury litigation, medical-legal or worker's compensation claims
• Arterial disease or stents that would exclude the use of a tourniquet