The increase of end-stage osteoarthritis (OA) in an increasingly younger population is directly correlated with the rising incidence of obesity. As a result, knee arthroplasty (KA), which is a definitive end-stage treatment option, is increasingly performed on working age people. Knowledge and understanding of the underlying factors that drive the ability for people to return to work is crucial. First and foremost, the investigators would have like to have a clear idea of the percentage of patients who return to work and at what time postoperatively. The investigators would also determine the different factors influencing employment in the patient population after undergoing a knee arthroplasty and register the evolution in the necessity of pain medication pre-and postoperatively. Ideally, the investigators can include a short questionnaire regarding return to sports to gather valuable information.