Clinical and Functional Outcomes of Unicondylar Knee Arthroplasty in Patients Aged 80 Years and Older: A Systematic Review

Abstract Background: The incidence of knee osteoarthritis (OA) increases with age. Unicondylar knee arthroplasty (UKA) has been proposed as a bone-preserving, faster-recovery alternative to total knee arthroplasty (TKA) for high-grade OA. However, the safety and effectiveness of UKA in patients aged ≥80 years remain controversial due to concerns about perioperative risks and implant survivorship. This systematic review evaluates UKA’s clinical, functional, and survivorship outcomes in octogenarians. Methods: PubMed, Embase, Scopus, and the Cochrane Library were systematically searched in accordance with PRISMA guidelines (PROSPERO: CRD420261290921). Eligible studies included patients aged ≥80 years undergoing UKA with reported clinical or functional outcomes, complications, or survivorship. Results: Eleven studies comprising 3266 patients (3,300 knees) aged ≥80 years were included. Mean age ranged from 82 to 84 years. Functional outcomes improved substantially: Knee Society Score increased from 32–46 to 81–91, Oxford Knee Score from 23.3 to 39.3, and Knee Injury and Osteoarthritis Outcome Score from 55.7 to 83.1. Pain scores and range of motion also improved significantly. Complication rates ranged from 4% to 22%, predominantly medical rather than orthopedic. Revision rates were low at 3% (1.8%–7%), and implant survival with durability exceeded the life expectancy of patients in most cases. Conclusions: UKA provides substantial pain relief, functional gains, and satisfactory survivorship in carefully selected octogenarians. It offers faster recovery and reduced perioperative morbidity, while the higher long-term revision risk appears less clinically significant in this age group. UKA should be considered a safe and effective option for elderly patients with isolated unicompartmental OA.