The number of working-age patients receiving total knee arthroplasty for end-stage knee osteoarthritis is rapidly rising. Working-age patients represent a relatively new group of patients, as they do not only expect pain relief and improved quality of life after surgery, but also want and need to participate in the workforce again. However, literature of total knee arthroplasty among working-age patients is scarce. The aim of this thesis was therefore to expand our knowledge of working-age patients receiving total knee arthroplasty, from their preoperative state to postoperative outcomes using a biopsychosocial approach, with a specific focus on work. It was found that working-age patients had positive outcomes after total knee arthroplasty...