I really can’t comment on the longevity of our newest-generation partial knee (aka uni-knee arthroplasty, or UKA) implants.
Historically, total knee replacements (aka total knee arthroplasty, or TKA) have nearly a 90% survivorship at 10-15 yrs. Newer-generation TKAs we expect to surpass that, but none of them have been around long enough to say.
Historically, UKAs have had only an 80% survivorship at 8-10 yrs, most of the failures likely due to flaws in implantation. Newer-generation UKAs are still seeing similiar results, but may have a slight improvement to this.
Newest-generation UKAs (ie- robotic) are seeing an astounding success in the short-term (3 yrs), with the added new possibility of continued resurfacing of other parts of the knee if they wear out in the future. Historically, if the partial knee was doing OK, but your arthritis progressed to the other side of your knee, your only option was a conversion to a TKA. Now, we can reliably implant a new UKA or patellofemoral joint (PFJ) knee arthroplasty to the other portions of your knee to match your original one.
So, many robotic, minimally-invasive & UKA surgeons believe that robotic UKAs have solved 2 major issues for failure of traditional UKAs: 1) less-than-perfect implantation and 2) progression of arthritis. Unfortunately, this technology is too new to tell. The first one ever placed in a human being was done in 2006.
Regardless of the longevity of the implant, you will find that the surgical impact to your knee, and the speed of recovery, is an order of magnitude easier than that of a TKA. For this reason, many of my patients request a robotic UKA, even accepting the potential for future surgeries (which also exists for TKA).