Total hip replacement (THR) prosthetic migration measurement in standard digital x-rays


A method to measure cup migration of total hip replacements in standard radiographs. It has been developed cooperatively by members of the Department of Orthopaedics and Traumatology at the Medical University of Innsbruck and the Institute for Basic Sciences in Engineering / Unit Geometry and Surveying at the University of Innsbruck, Austria, since 1984.

It is possible to measure longitudinal/transversal migration of acetabular cup in digital serial radiographs (minimum of 4 x-rays per series). Full size AP pelvis radiographs are required.

Accuracy +/- 1mm.


An extension for measurement of femoral components was added in 1998.

It is possible to measure of longitudinal/transversal migration of femoral components in digital serial radiographs (minimum of 4 x-rays per series). Applicable to AP radiographs of pelvis or hip. The tip of stem must be visible.

Accuracy +/- 1.5mm.


A detailed description of the method was published in: Krismer M., Bauer R., Tschupik J.P., Mayrhofer P.: EBRA: A METHOD TO MEASURE MIGRATION OF ACETABULAR COMPONENTS - TECHNICAL NOTE, J.Biomechanics, Vol. 28, No. 10, pp. 1225-1236, Pergamon, 1995. 


  • total hip replacement THR
  • migration measurement
  • standard digital x-rays
  • no artificial landmarks
  • retrospective studies
  • acetabular component
  • femoral component
  • +/-1mm accuracy (cup)
  • +/-1.5mm accuracy (stem)
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