Unicompartmental knee arthroplasty
Unicompartmental knee arthroplasty (UKA) is a surgical procedure used to relieve arthritis in one of the knee compartments in which the damaged parts of the knee are replaced. UKA surgery may reduce post-operative pain and have a shorter recovery period than a total knee replacement procedure, particularly in people over 75 years of age.
Source: Wikipedia — Unicompartmental knee arthroplasty (CC BY-SA 4.0)