In orthopaedic surgery, clinical decisions must often be made with imperfect information from observational studies and limited resources. Decision analysis and cost-effectiveness analysis have emerged as evidence-based tools to assist in making choices in situations in which uncertainty exists. This review demonstrates how decision-analysis and cost-effectiveness-analysis tools can be used to expand on published observational studies within the context of a specific clinical scenario. Critical evaluation of clinical and economic data is of increasing importance in today's health-care delivery climate. The use of decision analysis and cost-effectiveness analysis as tools to augment observational studies can assist clinicians, patients, and policy makers in choosing techniques that will optimize benefits. A clear understanding of and the ability to use and apply these tools will allow surgeons to participate effectively in health-policy decisions to enhance the overall quality and efficiency of care that is delivered.