The aim of the study is to identify the patients who may benefit from the unicompartmental knee prosthesis by reducing the application of the total knee arthroplasty used as a method of overtreatment with total knee prosthesis. In this regard, a comparative case study was organized between two clinical cases: S1 - female, aged 58, with a diagnosis of stage 2 gonarthrosis, left side, and S2 - female, aged 55, with a diagnosis of stage 2 gonarthrosis, left side. Methods of measurement (exploration, evaluation) used: anamnesis (interview method), somatoscopic examination, palpation (information on skin temperature, detection of painful spots on movement or traction) and evaluation (joints and muscles testing). Following the research, we confirmed the fact that the functional recovery is faster and the pain is less intense after the unicompartmental knee arthroplasty performed correctly, with a suitable prothesis. This is an efficient treatment for gonarthrosis, which involves maintaining the cortical projection of the knee, keeping the proprioceptors in the cruciate ligaments and the healthy meniscus.