 Confidentiality All data will kept in a locked filing cabinet and office for 25 years, and only research staff will have access to it. The data will be analyzed using various computer programs, such as Gaitview 2002, Microsoft Office programs, and SPSS for statistical analysis. The data on these programs will only be available to research staff via a secure password. Names of patients will only be available to research staff, and numerical codes will be used in any presentations or publications of the data. The research team will collect and use only the information they need to judge the safety and usefulness of the study. This information will only be used for the purposes of this study. 