With the heightened interest in protocols to prevent or treat complications of haemophilia related to recurrent haemarthroses, there is a need for sensitive joint-evaluation tools. The World Federation of Haemophilia (WFH) Physical Joint Examination instrument, which was developed for persons with haemophilia worldwide, is not sensitive enough to detect early structural or functional abnormalities. Therefore, we have expanded the WFH instrument to detect more subtle abnormalities of joint structure and function, and in addition, developed a new scale specifically tailored to the dynamic growth and gait development of children. We compared the original and three new instruments in 43 children with haemophilia. The three new scales all showed better correlation with the WFH pain instrument than did the original WFH physical examination instrument (P < 0.01 for each of the new instruments vs. P > 0.05 for the WFH instrument). In addition, results of the new child physical examination instrument best conformed to a normal distribution (P=0.35) and this instrument had better overall statistical performance. This instrument should be studied further in prospective, longitudinal clinical trials of young children.