BACKGROUND: Literature regarding outcomes in patients over 80years old after total knee arthroplasty (TKA) is inconsistent. We aimed to compare implant survivorship and functional outcomes between elderly patients (??80years) and younger patients (?0.05), nor regarding maximum flexion (121°?±?12 and 117°?±?13, p?=?0.08). The implant survivorship was 100.0% after a mean 64.4-month follow-up (range 60-78), without revision requiring removal of the implant in any group. The survival rate without any reoperation was 97.6% (95% CI 93.0-100.0) in the elderly group and 95.9% (95% CI 92.5-99.5) in the younger group (p?=?0.64).CONCLUSION: At a minimum of 5-year follow-up, there was no revision surgery and a very low rate of complications requiring reoperations both in the group over 80years of age and in the younger population, with the use of a PS prosthesis. The functional results were slightly lower for elderly patients and correlate with the lower functional demands of this population. The indication for TKA, especially with a PS implant, may be encouraged in appropriately selected elderly patients.LEVEL OF EVIDENCE: III (retrospective cohort study).