Fifty patients (100 knees) were randomized to receive both an anterior-stabilized (AS) implant and posterior-stabilized (PS) implant for use in a same-day bilateral total knee arthroplasty (TKA) procedure. The primary outcome of interest was anteroposterior (AP) stability, measured radiographically for static AP stability and with one-leg standing lateral fluoroscopic imaging for dynamic AP stability. Additional outcomes of interest included the Knee Society Score (pain, function, total) and the Western Ontario and McMaster University Osteoarthritis (WOMAC) index (pain, stiffness, function, total), femorotibial angle, flexion contracture, range of motion, polyethylene insert thickness, and femoral rollback. Results revealed significant differences in posterior displacement and static AP laxity between the AS-TKA and PS-TKA groups. Furthermore, femoral rollback was significantly inferior in the AS-TKA group compared to the PS-TKA group. No significant differences in KSS or WOMAC scores, tibial displacement (at 30, 60 and 90 degrees of knee flexion), femorotibial angle, flexion contracture, range of motion or polyethylene insert thickness were observed between the two groups.