UKA Manual Versus UKA MAKO Robotic

Eligibility Details: Inclusion Criteria: - All patients who receive a robotic arm assisted UKA using the RIO navigation system will be prospectively included. All patients who have received a medial fixed or mobile UKA performed by surgeons in the Joint Preservation, Resurfacing, and Replacement Service at Washington University will be retrospectively reviewed. Also, all TKAs from a pervious study (IRB 201308057) performed by surgeons in the Joint Preservation, Resurfacing, and Replacement Service at Washington University will be retrospectively reviewed as well. - Patient is willing and able to comply with postoperative follow-up requirements and self-evaluations - Patient is willing to sign an IRB approved informed consent - Patient is at least 18 years of age Exclusion Criteria: - • Patient has a BMI < 40 - Patient is skeletally immature - Patient has an active infection or suspected infection in or about the joint - Bone stock that is inadequate to support fixation of the prosthesis - Neuromuscular disorders, muscular atrophy or vascular deficiency in the affected limb rendering the procedure unjustified. - Patients with mental or neurological conditions which may be incapable of following instructions. - Blood supply limitations - Collateral ligament insufficiency. - Patients with prior HTOs or Unis. - Patients requiring bilateral knee arthroplasty.