Many studies support the use of the unicompartmental knee arthroplasty (UKA). It's been shown to have a faster rehab time, give better function, and cost less than a total knee replacement.
Failure in a small number of cases does occur. There are several reasons why this can happen. Sometimes the arthritis continues to get worse. The bone around the implant wears away and the implant loosens.
n other patients the hip, knee, and ankle don't line up as well as they used to. Finally, overcorrecting a deformity at the time of surgery can cause too much load on the knee joint. The wear and tear on bone and ligaments can lead to failure of the implant.
It may still be possible to salvage your "new" knee. Sometimes surgery to revise the implant is the answer. In other cases, replacing the unicompartmental implant with a total knee replacement is the next step. Be sure and ask your doctor what are your options. Perhaps get a second opinion from another surgeon.