Preoperative Optimisation prior to Hip and Knee Arthroplasty (PrOpE) Many patients scheduled for planned hip or knee replacement surgery have health conditions that may affect recovery, such as reduced physical fitness, nutritional problems, multiple medications, or increased stress and anxiety. These factors can increase the risk of complications and delay recovery after surgery. The PrOpE study examines whether a structured preparation programme before surgery, known as preoperative optimization or prehabilitation, can be safely implemented and may support recovery after hip or knee replacement. Aim of the study The main aim is to assess the feasibility of a comprehensive preoperative optimisation programme and to explore its potential effects on recovery and health outcomes. The results will help improve future care for patients undergoing major orthopaedic surgery. Who can participate? Adult patients scheduled for elective total hip or knee replacement surgery who are classified as ASA \>2, aged between 18 and 99 years old and without a severe cognitive impairment. Participation is voluntary. Study design A total of 180 participants will be included and randomly assigned to one of two groups: • Standard Care Group: Participants receive usual medical care before and after surgery. • Intervention Group: In addition to standard care, participants receive an individualised preparation programme over several weeks before surgery. This programme may include: * Personalised physical exercise * Nutritional assessment and advice * Support for stress, pain, and mental well-being * Review of regular medications Some elements may be delivered at home or via telemedicine, depending on individual needs. What information is collected? The study evaluates recovery after surgery, including complications, length of hospital stay, physical function, quality of life, and use of health care services. Questionnaires, physical tests, and blood samples are used to better understand health status before and after surgery. Risks and benefits The study involves low additional risk. All measures are adapted to individual abilities and supervised by trained professionals. The main burden is the additional time required for participation. Participants in the optimisation group may benefit from improved preparation for surgery. The study also contributes to improving care for future patients.