© Unit Geometry and CAD, University of Innsbruck, Austria

University of Innsbruck, Austria / Program by C. Brunhuber, November 2002

EBRA is a method for migration measurement of Total Hip Replacements in standard pelvic AP-radiographs. It has been developed cooperatively by members of the Department of Orthopedics and the Department of Mathematics and Geometry at the University ofInnsbruck, Austria, since 1984.

EBRA Release 2012 is the most recent software version for measurement in digital radiographs saved in JPG-, GIF- or BMP- fileformat. It is a standalone VisualBasic program running completely independent from the former used basic image analysis package OPTIMATE.

(1) Getting an overview over the radiographic series

Load all images of the series by using the command new Window in the File-Menue. Then display them simultaneously with the command Tile in the WINDOWS-Taskbar (right click). Try to find the clearest pelvic contoures which are visible in all radiographs of the series. Especially sacral foramina at the top of the picture may be cut off !

(2) Choosing the best pelvic reference lines

The basic line of the EBRA-reference-system may be either a line tangent to both foramina obturatoria or to the caudal contoures of the pelvic bone. Chosen once it must remain the same throughout the whole series (This is valid for all reference lines!). The second horizontal line may be tangent to the upper margin of the pubic ramus or to one of the teardrop-figures or - if the first line was chosen at the caudal contour of the pelvic bone - to one of the foramina obturatoria. The third (uppermost) horizontal line may be chosen tangent to one of the sacral foramina. Be careful to identify always the same foramen throughout the whole series!

(3) Making up the decision on the type of evaluation

If you are in doubt which type of evaluation will be suited for your type of hip socket use the corresponding help text Supported Types of Hip Sockets. The evaluation may be based on either the contour of the spherical head (if it is clearly visible) or on that of the cup. If the rim of the cup is circular ist may be used for calculation of inclination and anteversion of the cup. Once chosen and filled in the data form the type of evaluation must remain the same for the whole series.

(4) Filling in the data form

Do not forget to fill in the correct date of the radiogram! Either the true head-diameter or the true cup size must be known for evaluation. The input of the focus-film-distance is optional. Knowledge and input of the exact focus-film-distance will enhance accurcy.

(5) Enhancing the image

If you want to use one of the Sharpen-options in the Image Tools-Menue you should apply it to all images of the series!

File

Open > open new image file

New Window > open new EBRA for simultaneous display of several images

Patient's Data > input patient's data

Reload Landmarks > reload original landmarks from BIN-file if they have been destroyed

Write Data > save results to data file

Exit > terminates the program

Zoom

Zoom+ > zoom in (= enlargement)

Zoom- > zoom out

Zoom with Mouse > zoom in by mouse click

CenterMode    > mouse position at click will be centered in the zoomed image

Image Tools

adjust Colors > adjustment of brightness and contrast

reset Colors > restores the original grey levels

sharpen > filtering (maybe a little time consuming in large images)

sharpen more > Use always the same sharpen option for all images of the series!

sharpen strong

invert > turns black into white

hardcopy > prints the current image

Measurement Tools

Head > input points of head contour (min = 3 points)

Cup > input points of cup contour (min = 3 points)

Rim > input points of rim or contrast wire (min = 5 points or exactly

3 points including the first 2 on the main axis of the ellipse)

enable Ruler > Optional line determining the angle of cup inclination

enable Cross > Setting of a horizontal and a vertical tangent to the cup contour

(for prostheses of type 9)

Calibrate > Input of 2 points and their known distance

in oder to calculate magnification

calc Distance > Utility for length measurement between 2 points (in calibrated millimeters)

reset Grid > restores the default grid of pelvic reference lines

Menue ?

About > Information on program version

Help > loads this help file

Register > enables setting of License Name and Expiration Date after input of License Key

Use Tab-Key for cursor positioning!

Date > the date of the radiograph in the order year-month-day (yyyymmdd)

Study-ID > an alphanumeric string chracterizing the patient´s membership in a certain study

Evaluation Type > a number from 1 to 9 corresponding with the type of prostheses. The Type 7a

stands for the SL-Cup by PROTEK

Head Diameter > head size in mm

Cup Diameter > cup size in mm

Focus Dist > optional input of radiographic focus distance (in mm) if known

Datafile > name of patient´s datafile without extension .DAT (it will be appended automatically)

These are the types of hip sockets supported by the EBRA-DIGITAL measurement software. For more information click on the corresponding icon.