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 WIBERG’S OR CENTER EDGE  (CE) ANGLE

The CE angle is one of the most frequently applied anatomic measures for the evaluation and description of the geometry of the hip in everyday orthopedic care. Measurements of CE angle in X-rays are valuable because you can determine and monitor objectively the severity of dysplasia, and establish the need for surgery and follow up the treatment. The CE angle is one of the most frequently applied anatomic measures for the evaluation and description of the geometry of the hip in everyday orthopedic care. Measurements of CE angle in X-rays are valuable because you can determine and monitor objectively the severity of dysplasia, and establish the need for surgery and follow up the treatment.

Wiberg’s or center edge  (CE) angle is formed at the juncture of the Perkin line with line drawn from the center of the femoral head to the outer edge of the acetabular roof. Measured on the Anterior Posterior hip radiographs the center edge angle  is usually described as lateral center-edge angle (LCEA) or measured  on the false-profile radiograph of the hip is  described as the anterior center edge angle (ACEA). The center edge angle may distinguish between acetabular insufficiency, under coverage  or overcoverage of the femoral head by the acetabulum

Center-Edge Angle  app is medical software aimed for orthopaedic surgeons, providing tools that allow doctors to:

               -Securely import medical images directly from the camera or stored photos 

               -Offers a very convenient way to determine the most accurate possibly lines in order to measure the angles. By the aid of a circular transparent template, the points of interest are marked accurately. The automatically formed lines, drawn between points, measure automatically the angles of interest. The results are printed in degrees. By inputting the age, the measured angle is compared with values from normal reference database. In case the measured angle is beyond the normal range for that age, the hips are categorized as normal, borderline dysplastic, dysplastic or severe dysplastic (<5) or over coveraged, pincer type femuracetabular impingement (FAI) of the  hip .

               -Save the planned images, for later review or consultation.

               All information received from the software output must be clinically reviewed regarding its plausibility before patient treatment! AI App is indicated for assisting healthcare professionals. Clinical judgment and experience are required to properly use the software. The software is not for primary image interpretation.

               The app is a handy tool for an orthopaedic surgeon, radiologist, medical student or resident who wants objectively to monitor and determine the severity of dysplasia of the hip. The build-in comparison feature with the normal reference values according to patient age may help decide what could be considered normal or  dysplastic or  pincer (FAI). The app is not a simple goniometer, is an enhanced product which offers the ability to compare all the input data with medical reference database. The results are printed on the screen and the hips are categorized as normal or dysplastic or severe dysplastic or pincer (FAI) according to the angle measured. This feature  it is particular useful especially in clinical settings where you need a quick results without losing time in looking for reference data according to age variations in huge textbook. The circular template to determine the points of interest and to mark them accurately are very useful in clinical settings where finding a sharpened pencil, a protractor and manage to draw with ruler lines over the patients x-rays is definitely a cumbersome and tedious task. You can load from your photo library or capture a photo from x-rays of the patient in you mobile phone or tablet, the App simply guides you to do the rest.

Reference

 

1.Wiberg G. The anatomy and roentgenographic appearance of a nor mal hip joint. Acta Chir Scand. 1939;83:7-38

2.Philippon MJ, Wolff AB, Briggs KK, Zehms CT, Kuppersmith DA. Acetabular rim reduction for the treatment of femoroacetabular impingement correlates with preoperative and postoperative center- edge angle. Arthroscopy. 2010;26:757-761.

3.James D. Wylie, Ashley L. Kapron, Christopher L. Peters, Stephen K. Aoki, Travis G. Maak Relationship Between the Lateral Center-Edge Angle and 3-Dimensional Acetabular CoverageOrthop J Sports Med. 2017 Apr; 5(4): Published online 2017 Apr 12. 

How to measure the Centre  Edge Angle of the hip joint with the App.


The centre edge app offers a very convenient way to measure the most accurate possibly the angle of Wiberg or CE angle.  This Is a tutorial video how to measure the CE angle.  Once  you  load one image from your photo library or capture a photo from x-rays photos of the patients. Next you insert  the age of the patient
      The circular template appears on the screen in order to determine the points ofinterest. By moving the template with a finger over the screen the template isfollowing the movement and the centre point helps to locate easily and mark the points accurately. You can also zoom in and out with both fingers. 

         The app offers two ways to measure: the 2AE method  (two Acetabular lateral edge method-quicker method measures  both hips at once) and the EXT method (extended method-single hip, most accurate). By default the 2AE is highlighted.

[2AE method]: Aiming with the transparent circular template to the right lateral acetabular edge you mark first the right lateral acetabular edge (P1 Point), by pressing the 'point' button.  Next you aim to locate the left lateral Acetabular edge and by clicking the 'point' button you mark the left lateral acetabular edge (P2 Point). After that a horizontal line (P1,P2) appears. The transparent circular template appears and you aim to locate the center first of the left femoral head by moving the template over the femoral head, trying to fit to a best-fit circle to the contour of femoral head circumference. By clicking the 'point' button the center of the left femoral head is marked (C3 Point) by  repeating the same task you locate the center of the left hip (C4 Point). The left and then the right CE angle over the hips are measured and the values in degrees are printed on the screen. The hips also are categorised as normal(<25) or borderline dysplastic (21-24) or dysplastic (>20) or severe dysplastic (<5) or overcoveraged hip (>40)-pincer type femoroacetabular impingement FAI.

[EXT  method]: Ιn cases where you have leg-length inequality, unilateral luxation of femoral head or THR or obliquity you can choose another way of measure the CE angle. By pressing the option 'Ext.' you activate another method of marking the points. First you try to mark two points first right (K1 right) and then left (K2 left) through the ischial tuberosities, tear drops, or inferior border of the obturator foramina  depending on which was more symmetric and accessible. A horizontal line is drawn (K1,K2) and appears on screen. The transparent circular template appears and you aim to locate the center of the femoral head of selected hip by moving the template over the femoral head, trying to fit to a best-fit circle to the contour of femoral head circumference. By clicking the 'point' button the center of the femoral head is marked (C3). Once you found the lateral acetabular border of the selected ipsilateral hip by clicking the 'point' button you mark lateral acetabular border (P4). The single CE angle value is printed over the screen near the measured hip. Please see tutorial videos at developer’s site.

Points order of 2AE method: P1 ->lateral Acetabular edge left, P2->lateral Acetabular edge Right, C3 ->center of the  right femoral head, C4-> center of the left femoral head.

 All information received from the software output must be clinically reviewed regarding its plausibility before patient treatment! CE App is indicated for assisting healthcare professionals. Clinical judgment and experience are required to properly use the software. The software is not for primary image interpretation.