Total knee arthroplasty remains the gold standard in the management of disabling gonarthrosis. Improved functional results, increased availability of care and an ageing population have all contributed to the rise in total knee replacement surgery in Western countries. Surgical techniques have been steadily improving for several decades in terms of implant positioning and joint alignment. However, 10% of patients are dissatisfied with the clinical and functional results. The challenge is to understand why these patients remain dissatisfied despite these surgical advances. Our aim is to understand the functional impact of knee prosthesis through a quantified analysis of gait, the performance of certain tasks of daily living, and pre- and post-operative proprioceptive assessments. We will link these results with patient feedback to identify factors potentially responsible for poor postoperative outcomes.