Safety and Efficacy of the Oxford Cementless Partial Knee System

Inclusion Criteria: * Patients with a preoperative Knee Society Assessment Score of \<70 * Patients undergoing primary partial knee arthroplasty as unilateral arthroplasty or bilateral arthroplasty, simultaneously or otherwise * Patients diagnosed with osteoarthritis or avascular necrosis limited to the medial compartment of the operative knee joint * Male or female patients who are at least 21 years of age at the time of surgery * Patients with full thickness cartilage loss, with or without bone loss in the medial compartment * Patients with functionally intact Anterior Cruciate Ligament (ACL) and Posterior Cruciate Ligament (PCL) * Patients who needs to obtain relief of pain and/or improved function in their knee * Patients with fixed flexion deformity \<15 degrees * Patients who are able to follow postoperative care instructions * Patients who are willing and able to return for scheduled follow-up evaluations * Patients in which natural alignment can be restored * Patients who have completed a valid, Institutional Review Board (IRB) approved Informed Consent Form * Patients with child-bearing potential who voluntarily agree to prevent pregnancy for 2 years following device implantation Exclusion Criteria: * Patients with a preoperative Knee Society Assessment Score of greater than or equal to 70 * Patients in which the device would be used to revise a failed prosthesis * Patients who are less than 21 years of age, at the time of surgery * Disease or damage to the latera…