Sun X, et al. - Authors compared the clinical outcomes of unicompartmental knee arthroplasty (UKA) revised to total knee arthroplasty (TKA) vs primary TKA. Findings suggested an association of the conversion of UKA to TKA with poorer clinical outcomes than primary TKA. Moreover, compared to performing primary TKA, conversion of UKA to TKA is more complicated. More augments, stems, and bone grafts and thicker polyethylene components were often required by revised UKA than primary TKA. Nonetheless, similar hospital stay, complications, and revision rate were seen in the patients who undergo conversion of UKA to TKA as patients who undergo primary TKA.