A medial Unicompartmental Knee Arthroplasty (UKA) is commonly performed in the presence of an isolated symptomatic medial femorotibial osteoarthritis in stable knees [1,2]. This is due to the advantages of a unicompartmental arthroplasty compared to a Total Knee Arthroplasty (TKA), i.e. preserved knee kinematics due to preservation of both cruciate ligaments, preservation of bone stock, faster recovery, and reduced mortality [1–7].