0
    247
    views

    Using Plain Radiographs to Measure Version in THA

    Optimum acetabular component positioning in total hip arthroplasty (THA) remains the holy grail for surgeons who perform total hip arthroplasty (THA). The Lewinnek safe zone was supposed to be it, but research has shown that even patients with a cup in the safe zone develop instability. [1]

    One of the issues, Thomas L. Bradbury, MD, believes, is that surgeons template in the coronal plane, which gives a good frontal representation of the body, but may not be adequate. Templating in the axial plane, he said, would give surgeons a better understanding of the version of the components.

    RELATED: Register for the 7th Annual ICJR South Hip & Knee Course

    That’s important because the ideal position of the cup and stem are interrelated, Dr. Bradbury said at the 6th Annual ICJR South Hip & Knee Course. Surgeons should be looking to achieve “the combination of femoral version, acetabular inclination, and acetabular version that allows maximal range of motion before impingement within the framework of the individual’s spino-pelvic kinematics.”

    He noted that the ideal combined version to prevent impingement is 37°, with the anterior pelvic plane in vertical and the inclination set at 40° to 42°. [2] In reality, version in the general population is highly variable. In a study of 300 trauma patients, CT scanograms of the uninjured femur showed a range of version from -17° to 48°. [3]

    Dr. Bradbury and his colleagues from Emory Orthopaedic and Spine Hospital in Atlanta, Georgia, have been investigating the use of plain radiographs – cross-table lateral and a modified Budin lateral of the femur – to measure combined version, as radiographs are easier to obtain routinely on patients than are CT scans. [4-6] This is an ongoing effort, with encouraging results so far: Dr. Bradbury and his colleagues have found the technique to be viable not only for evaluating version in patients with an unstable total hip, but also for evaluating patients undergoing primary THA. [7]

    During his presentation, Dr. Bradbury reviewed the steps for measuring combined version and used examples from his patient population to demonstrate how it is applied. Click the image above to watch Dr. Bradbury’s presentation and learn more about this technique.

    Disclosures

    Dr. Bradbury has no disclosures relevant to this presentation.

    References

    1. Abdel MP, von Roth P, Jennings MT, Hanssen AD, Pagnano MW. What safe zone? The vast majority of dislocated THAs are within the Lewinnek safe zone for acetabular component position. Clin Orthop Relat Res. 2016 Feb;474(2):386-91. doi: 10.1007/s11999-015-4432-5.
    2. Widmer KH. Zurfluh B. Compliant positioning of total hip components for optimal range of motion. J Orthop Res. 2004 Jul;22(4):815-21.
    3. Decker S. Suero EM, Hawi N, Müller CW, Kretteck C, Citak M. The physiological range of femoral antetorsion. Skeletal Radiol. 2013 Nov;42(11):1501-5. doi: 10.1007/s00256-013-1687-3. Epub 2013 Jul 16.
    4. Tiberi JV, Pulos N Kertzner M, Schmalzried TP. A more reliable method to assess acetabular component position. Clin Orthop Relat Res. 2012 Feb;470(2):471-6. doi: 10.1007/s11999-011-2006-8.
    5. Budin E. Chandler E. Measurement of femoral neck anteversion by a direct method. Radiology. 1957 Aug;69(2):209-13.
    6. Lee YK, Kim TY, Ha YC, Kang BJ, Koo KH. Radiological measurement of femoral stem version using a modified Budin method. Bone Joint J. 2013 Jul;95-B(7):877-80. doi: 10.1302/0301-620X.95B7.31195.
    7. Boissonneult AR, Hiranaka T, Robertson JR, Bradbury TL. A validated single-view radiographic alternative to computed tomography for the measurement of femoral anteversion: a method-comparison study. J. Arthroplasty. 2017 Mar;32(3):1018-1023. doi: 10.1016/j.arth.2016.09.016. Epub 2016 Sep 28.