On the prevention and analysis of missing data in randomized clinical trials: the state of the art.

We summarize and elaborate on the recently published National Research Council report entitled "The Prevention and Treatment of Missing Data in Clinical Trials." We tailor our discussion to orthopaedic trials. In particular, we discuss the intent-to-treat principle, review study design and prevention ideas to minimize missing data, and present state-of-the-art sensitivity analysis methods for analyzing and reporting the results of studies with missing data.