SOCIAL OUTREACH The reliability, validity and prognostic value of anatomic and functional classifications of fractures in traumatology focusing on upper limb Popularised summary This master's thesis explores the role of classification systems for collarbone (clavicle) and upper arm (humerus) fractures in enhancing diagnosis, optimising treatment, and improving prognosis prediction. Doctors use a variety of classification systems to classify a fractured clavicle or upper arm and determine the most suitable treatment. A classification system that is well-designed enables physicians to work with greater precision and offers insights into the healing process and recovery prospects. Unfortunately, not all systems are of the same level of reliability. Different physicians may classify the same fracture differently due to the complexity of certain classification systems. This can lead to misguiding diagnoses and treatment recommendations for the same fracture, causing inconsistencies. Despite the development of numerous classification systems over the years, it is still unclear which ones are genuinely beneficial in practice. This thesis focuses on identifying the most reliable classification systems for clavicle and upper arm fractures, their prognostic value, and the improvements required to enhance their efficacy. The study suggests a significant requirement for more standardised and user-friendly systems that can make the treatment process for patients with fractures more consistent and reliable. It is therefore crucial that doctors develop a unified approach to fracture classification through their training, ensuring consistent application with the ultimate goal of improving patient recovery outcomes. Societal importance Upper arm and collarbone fractures are common and can significantly affect patients' mobility and quality of life. Therefore, it is critical that these fractures receive treatment as effectively as possible. Only a good classification system can contribute to this, as inaccuracies in these systems can lead to suboptimal treatments and longer rehabilitation periods, potentially resulting in long-term limitations for the patient. This study offers valuable insights into the most reliable classifications and potential enhancements to existing systems. This could influence the quality of care, allowing patients to receive a correct diagnosis and appropriate treatment more quickly and to be better informed about their chances of recovery. A more reliable classification of fractures and targeted treatment can reduce the number of complications and procedures, potentially lowering healthcare costs. This research not only contributes to scientific advancement but also improves the quality of life for patients and the efficiency of healthcare.