How Long Does a Partial Knee Replacement Last?

If you are considering a partial knee replacement, one of the first questions you will ask is: how long will it last? The honest answer is that modern UKAs regularly last 15–20 years, and many patients never need further surgery. The key is matching the right patient to the right implant and managing the knee well after surgery.

Registry data from the UK, Australia and Scandinavia show 10-year survival rates of 92–95% for modern medial UKA implants. At 15 years, survival is 85–90%, and at 20 years it remains above 80% for well-selected patients. These figures are comparable to total knee replacement, with the added benefit that revision surgery — if it is ever needed — is usually straightforward because the bone and ligaments have been preserved.

Patient selection is the single biggest factor in longevity. The KOGS grading system used in our practice scores four criteria objectively: the pattern of arthritis, ligament integrity, correctability of deformity and bone quality. Patients who score well on KOGS have measurably lower revision rates because the untouched compartments of the knee are healthy enough to share the load for decades.

What you do after surgery matters almost as much as the surgery itself. High-impact activities — running, jumping sports, heavy repetitive lifting — can accelerate polyethylene wear. Low-impact activities — walking, cycling, swimming, golf, tennis — are not only safe but protective because they keep the supporting muscles strong and the joint well-lubricated. Most patients are back to full recreational activity by 3–4 months.

Weight management and general health also influence implant survival. Every extra kilogram increases joint reaction force by roughly four kilograms during walking. Maintaining a healthy body mass index, controlling blood sugar if you are diabetic, and avoiding smoking all reduce the risk of implant-related complications and extend the functional life of the replacement.

If arthritis does eventually develop in another compartment, the conversion to a total knee replacement is not an emergency. It is planned electively when symptoms warrant it, and the outcomes are similar to a primary total knee replacement because the bone stock and ligaments have been protected. For the right patient, UKA is not a temporary fix — it is a durable, long-term solution.