Two hundred sixty-four patients with primary osteoarthritis, class I or II obesity (BMI 30–40 kg/m²), and varus deformity <15° were randomized to receive either a standard nonstemmed tibial component (n=134) or a long-stemmed tibial component (n=130) during total knee arthroplasty. The primary outcome of interest was aseptic tibial loosening. Secondary outcomes included Knee Society Scores (KSS), hip–knee–ankle (HKA) angle correction, radiographic findings (including radiolucent lines), and complication rates. Outcomes were assessed up to a mean of 6.1 years postoperatively. Overall, the results of the study revealed no significant difference in clinical or radiographic outcomes between the groups, and no aseptic loosening occurred in either group. The main finding suggests that long-stemmed tibiae do not confer additional benefit over standard components in this patient population.