Inclusion Criteria:  English fluency and literacy Able to provide informed consent Males or females, > 18 years of age and < 89 Indicated for unicompartmental knee arthroplasty based on a series of existing weight bearing knee plain radiographs Have equivocal weight bearing knee radiographs, in which the indication for UKA vs. TKA is not clear Meet the following criteria: no inflammatory arthritis, intact Anterior cruciate ligament, no fixed varus deformity > 10 degrees, no fixed valgus deformity > 5 degrees, knee range of motion > 90 degrees, no patellofemoral arthritis  Exclusion Criteria:  Males or females < 18 years of age and >89 Prisoners Patient who have existing radiographic evidence of tricompartmental OA Patients with inflammatory arthritis, anterior cruciate ligament deficiency, fixed varus deformity > 10 degrees, fixed valgus deformity > 5 degrees, knee range of motion < 90 degrees, patellofemoral arthritis