IntroductionMost of the available database management systems for clinical gait laboratories lack the integration of all routinely acquired data sets in their device specific data format, a standardized graphical user interface, a fully relational database design, customizable interfaces and retrieval procedures. The purpose of this study was therefore to develop a user friendly relational database with all these abilities for several gait analysis systems.MethodologyWe decided to use IBM-compatible personal computers (PC) with MS-DOS 6.0 and with Microsoft Windows 3.1 as graphical user interface. MS Access 2.0 for Windows as a relational database management system (RDBMS) with an easy understandable programming language (Access Basic) was chosen for the development of the database and MS Excel for Windows for the graphical data output. System requirements are an IBM-compatible PC with 80486 processors or higher, a hard disk drive, 16 megabytes of random-access memory, 17-inch display and a graphics board for the 1024-by-768-pixel mode. A network connection to a central data server is recommended.ResultsThe 'two-file approach' was chosen for the database: one file contains the data (back-end) and may be placed on a server, the other file (front-end) contains the queries, forms and program modules and may be distributed on several workstations (with a network connection to the server). An adequate relational database structure with referential integrity and with a security system on database level was designed for the back-end: one table contains basic informations about the patients (e.g. ID, name, date of birth, sex, address, diagnosis etc.). Data concerning the examination date (e.g. corresponding text, weight, height etc.) are stored in a separate related table. Every patient can be assigned to one or more studies. Text files from several word processors concerning the results of the examination can be imported. Several tables exist for the temporal/spatial and the dynamic foot pressure distribution data, the time normalized kinematics/kinetics and EMG data. The raw EMG and dynamic foot pressure distribution data are stored in binary-large-object (BLOB) fields.We use a MotionAnalysis system (OrthoTrack software) for the measurement and calculation of 3-D-kinematic and -kinetic data and developed a program for the export and time-normalization (to the stride period of 100% with 1% intervals) of this data. Export programs for other systems could be developed by their vendors. The import of the temporal/spatial and time normalized kinematic/kinetic data and the calculation of the group ensemble averages (after visual control of the single trial plots) is performed by the database program itself.The database front-end contains one main form for the selection of one of the following functions:1) add, view, edit and delete basic data, examination date and group data. There are functions for searching and filtering with several criteria;2) view and print this data as continuous data sheets. Criteria can be specified to limit the displayed records;3) graphical data output in standard charts by automatic data transfer to MS Excel via DDE. Currently available are the following plots of the 3-D-kinematics and -kinetics (joint moments and powers) of the lower extremities or 3-D-kinematics of the trunk:a) several trials or the ensemble averages +/- 1 SD (as a grey band) of one sideb) right and left side and reference values +/- 1 SD as a grey bandc) data of different groups or examination dates (e.g. before and after therapy) and reference values +/- 1 SD as a grey band;4) automatic data retrieval for statistical assessment (e.g. the maximum knee flexion during swing phase of all patients belonging to the 'inhibitive casting' study before and after therapy). Currently available are values belonging to several events (e.g. initial contact, toe off) and maximum, minimum, ROM or mean values of several phases of the gait cycle;5) graphical output of the raw and processed EMG and dynamic foot pressure distribution data; and6) data import and calculation of group ensemble averages.DiscussionWe applied GaitBase over the period of one year during the routine work in our gait analysis laboratory. We found that GaitBase simplified some routine data management routines and provides us with a useful tool that can easily be customized to interface to different measurement devices and data analysis and presentation procedures. The relational database structure of GaitBase and the integration of time normalized kinematic, kinetic and EMG data simplifies their statistical evaluation. The two-file approach (front- and back-end) avoids problems with program updates and multiuser environments. The automatic data transfer to spreadsheet files for graphical output allows the transfer of selected records in a widespread data format. As the program uses only well documented comercially available software packages it can be easily customized by the user. The user is able to define queries on the whole data collection. Extensions for the storage of data concerning the energy consumption and import programs for other measurement systems are planned.