This is a long-term follow-up report of all-polyethylene tibial components in 60 years and younger, active patients. At the mean follow-up of 12.4 ± 2.7 (range, 10-18 years), no more patients were deceased or lost to follow-up, leaving 32 patients (44 knees) for final analysis. Good to excellent results were achieved in 96% of patients. The mean Western Ontario and McMaster Universities Osteoarthritis Index and Knee Society Score were 31 and 97, respectively. Sixty-two percent of patients were participating in sport activities such as running, gym exercises, and playing tennis or golf, with a mean UCLA score of 7.2. There were no cases of malalignment, aseptic loosening, excessive wear, or osteolysis. Seven patients (9 knees) had incomplete, nonprogressive demarcation at the zone 1 tibial interface. Kaplan-Meier survivorship at 10 years for revision due to mechanical reasons and for all failures was 97.7% and 95.5%, respectively.