Lack of enrollment

The purpose of this study is to determine if there is a patient satisfaction preference of Fixed Bearing versus Mobile Bearing Unicompartmental Knee Arthroplasty (UKA) in patients who are at a minimum two years post operative. Patient reported outcomes and expectations will be analyzed along with all retrospective chart data in patient with a Fixed Bearing or a Mobile Bearing UKA in one or both knees.

Inclusion Criteria:

1. Must be able to read, understand and provide written informed consent on the Institutional Review Board (IRB) approved Informed Consent Form (ICF)
2. Ability to understand and provide written authorization for use and disclosure of personal health information.
3. Subject who are able and willing to comply with the study protocol and follow-up visit.
4. Must be 18 years or older to participate.
5. Subjects must have a clinically documented Osteoarthritis in a knee, single or multiple compartments,
6. Subjects must have undergone a FB UKA or MB UKA in one and or both knees. MB UKA or FB UKA patients revised to Total Knee Arthroplasty (TKA) are eligible to enroll.
7. Must be a minimum 2 year (24 months) post-surgery on the knee.
8. The UKA operation must have been performed by the Investigator.
9. Subjects must be able to return for the follow-up appointment, and have the mental capacity to cooperate with PRO's, questionnaires, physical exam and imaging studies.

Exclusion Criteria:

1. Subjects with Bicompartmental UKA (i.e. medical or lateral UKA combined with Patello Femoral Joint (PFJ) (UKA)
2. Women who are pregnant.

Patients that have undergone a Unicompartment Knee Replacement with a Fixed Bearing or Mobile Bearing prosthesis.