TKR With and Without the Use of Intra-operative Sensing

Inclusion Criteria: * Patients who meet the indications for use for primary TKR using IOS * Subject must be diagnosed with osteoarthritis * Subject is likely to be available for all study visits * Subject is able and willing to sign the informed consent and follow study procedures Exclusion Criteria: * Revision total knee arthroplasty * Patient is receiving treatment for any of the following conditions: 1. Avascular Necrosis 2. Inflammatory arthritis 3. Post-traumatic arthritis * Any knee surgery other than meniscectomy (can be arthroscopic or open) * Ligament insufficiencies, prior surgeries such as anterior cruciate ligament (ACL) or posterior cruciate ligament (PCL) reconstructions, posterolateral reconstructions, osteotomies, tibia plateau fractures * Ipsilateral foot/ankle and hip arthritis * Range of motion less than 90° * Subject has a mental condition that may interfere with the subject's ability to give an informed consent or willingness to fulfill the study requirements (i.e. severe mental retardation such that the Subject cannot understand the informed consent process, global dementia, prior strokes that interfere with the Subject's cognitive abilities, senile dementia, and Alzheimer's Disease) * Any subjects meeting any contraindication criteria as identified in the locally approved labeling for the device should be excluded from this study. * Patient out-of-state with medication prescription not registered in iStop database * Patients with severe contralateral osteoarthritis requiring subsequent knee replacement or with a flexion contracture greater than 10 degrees.