A Single Time-Point Study to Evaluate the ConforMIS iTotal (PS) Knee Replacement System Versus Off-the-Shelf

This is a prospective, single-time point study that will be conducted in the US.To compare
outcomes of these two study groups, this study will include routine office questionnaires
such as the Knee Society Score (KSS) and the Knee Injury and Osteoarthritis Outcome Score
(KOOS).The functional testing used in this study consists of tests that physical therapists
use daily as objective methods to assess patients' functional status. The testing is designed
to closely mimic daily activities with which the subjects are familiar.

Inclusion Criteria:

- Implant must be a minimum of 6 months post-op and doing well in the opinion of site
staff

- Subject has had a knee replacement utilizing a fixed bearing PS (Posterior Stabilized)
implant design

- > 18 years of age

- Willingness to participate in the clinical study, to give informed consent, and to
perform all evaluations

Exclusion Criteria:

- Simultaneous or staged bilateral procedure

- BMI > 40

- Other physical disability that requires an aid for walking or disability affecting the
hips, spine, contralateral knee or other joint that limits function

- Participation in another clinical study which would confound results

- Inability to complete the protocol in the opinion of the clinical staff due to safety
or other reasons