For orthopaedic care of patients to continue to improve, new approaches, both diagnostic and therapeutic, must be continually developed. To verify that a new approach actually provides improved outcomes, these innovations must be subjected to rigorous scientific study. However, because outcomes of clinical interventions only can be studied in human subjects, these studies must not only meet scientific criteria, they also must meet strict ethical criteria. The Declaration of Helsinki, a document prepared by the World Medical Association that originally was written in 1964, revised substantially in 1975, and most recently revised in 1996, provides guidelines for such studies. In addition to satisfying ethical requirements, clinical investigators also face various complex issues that must be dealt with in the performance of clinical research studies. One of the most difficult issues is the conflict between a physician's concern for the well-being of his or her patients and the need for protocol driven trials. No matter how enthusiastic surgeons may be about a new therapeutic approach, they must recognize that they are responsible to scientifically validate their innovative approach with a well controlled clinical trial using valid functional outcome measures.