Two hundred and sixteen patients with advanced osteoarthritis scheduled for primary total knee arthroplasty (TKA) were randomized to receive one of three TKA prosthetic designs from the same system: cruciate-retaining (CR; n=72), anterior-stabilized (AS; n=72), or posterior-stabilized (PS; n=72). The primary outcome of interest was the mean score of all five subscales of the Knee injury and Osteoarthritis Outcome Score (KOOS) measured at a two-year follow-up appointment. Secondary outcomes included individual KOOS subscales, Oxford Knee Score, EuroQol five-dimension health questionnaire, EuroQol visual analogue scale, range of motion, and patient satisfaction. Outcomes were assessed up to two years postoperatively. Overall, patients reported similar levels of pain, function, satisfaction, and general health in all three prosthetic design groups. However, the PS group demonstrated statistically better range of motion, particularly in maximal flexion.