CupAnteversionInclinationApp

In Total hip Arthroplasty the orientation, namely anteversion and inclination of the new acetabular component -cup- influences wear, range of movement (ROM), and the likelihood of dislocation after total hip replacement (THR). Evaluating objectively of the cup anteversion, and inclination in hip arthroplasty replacement surgery is of paramount importance. Radiographs are the most important diagnostic means in the follow-up for evaluation of a total hip arthroplasty. Measuring anteversion and inclination in everyday clinical setting is a cumbersome work for a medical doctor. Computation requires a calculator, which requires an additional effort during practice and slows down workflow.

The App is medical software aimed for orthopaedic surgeons, providing a tool that allow doctors to:

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

-By marking certain anatomical landmark and points in a simple standard AP pelvic radiograph, values for cup inclination and anteversion are being calculated. The app is based on Widmer’s method which is the proven that is the most accurate compared to others.

-Pelvic tilt expressed by the angle APP is incorporated in measurements and can be adjusted manually according to surgeons preference.

-Radiographic Inclination (RI) and Radiographic Anteversion (RA) values are adjusted by taking into account pelvic tilt (APP angle).

- RI or RA values are printed in red or green, according to measured value in cases these are in certain range (Lewinnek at al), indicating if the positioning of the cup is optimal (green) or not (red).

-The data are printed over to screen so each case can easily assessed.

-For more accurate results the source of central ray of the x-ray should be at position at 1150mm away from x ray table .

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

The app offers an easy way to quantify cup anteversion and inclination a quick and comfortable manner without the use of a goniometer or a ruler or to calculate elaborated formulas.

All information received from the software output must be clinically reviewed regarding its plausibility before patient treatment! The 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.

In a busy THA practice, the examiner to draw lines in X-rays, it is time consuming and cumbersome to calculate mathematics.This App is particular useful in clinical settings where you need a quick results without losing time. Please see tutorial videos at the developer’s web site www.orthopractis.com

Reference

1. Nomura T, Naito M, et al .An analysis of the best method for evaluating anteversion of the acetabular component after total hip replacement on plain radiographs. Bone Joint J. 2014 May;96-B(5):597-603.

2. Bachhal V, Jindal N, Saini G, Sament R, Kumar V, Chouhan D, Dhillon M. A new method of measuring acetabular cup antev-

ersion on simulated radiographs. Int Orthop. 2012;36:1813–1818.

3. Widmer KH A simplified method to determine acetabular cup anteversion from plain radiographs. J Arthroplasty. 2004 Apr;19(3):387-90.

5. Murray DW: The definition and measurement of acetabular orientation. J Bone Joint Surg Br 1993 75:228,

6. Lewinnek GE, Lewis JL, Tarr R, Compere CL, Zimmerman JR. Dislocations after total hip-replacement arthroplasties. J Bone Joint Surg Am. 1978;60:217–220

7. Schwarz TJ et al. Correction of Pelvic Tilt and Pelvic Rotation in Cup Measurement after THA - An Experimental Study. Rofo. 2017 Sep;189(9):864-873.