Archives of Orthopaedic and Trauma Surgery

, Volume 138, Issue 8, pp 1045–1052 | Cite as

Assessment of pelvic tilt in anteroposterior radiographs by means of tilt ratios

  • T. Schwarz
  • A. Benditz
  • H.-R. Springorum
  • J. Matussek
  • G. Heers
  • M. Weber
  • T. Renkawitz
  • J. Grifka
  • B. Craiovan
Orthopaedic Surgery



In anteposterior (AP) radiographs, cup position in total hip arthroplasty and acetabular anatomy in hip-preserving surgery are highly influenced by pelvic tilt. The sagittal rotation of the anterior pelvic plane is an important measurement of pelvic tilt during hip surgery. Thus, correct evaluation of cup position and acetabular parameters requires the assessment of pelvic tilt in AP radiographs.


Changes in pelvic tilt inversely change the height of the lesser pelvis and the obturator foramen in AP radiographs. Tilt ratios were calculated by means of these two parameters in simulated radiographs for ten male and ten female pelvises in defined tilt positions. A tilt formula obtained by exponential regression analysis was evaluated by two blinded investigators by means of 14 simulated AP radiographs of the pelvis with pelvic tilts ranging from + 15° to − 15°.


No differences were found between male and female tilt ratios for each 5° step of simulated pelvic tilt. Pelvic tilt and tilt ratios correlated exponentially. Using the tilt formula, the two blinded investigators were able to assess pelvic tilt with high conformity, a mean relative error of + 0.4° (SD ± 4.6°), and a mean absolute error of 3.9° (SD ± 2.3°). Neutral pelvic tilt is indicated by a tilt ratio of 0.5 when the height of the lesser pelvis is twice the height of the obturator foramen.


The analysis and interpretation of cup position and acetabular parameters may be improved by our method for assessing pelvic tilt in AP radiographs.


Pelvic tilt Cup position Anterior pelvic plane Total hip arthroplasty Acetabular parameters 



There is no funding source.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical approval

This study is a retrospective analysis of data obtained in a registered, prospective, controlled trial (DRKS00000739, German Clinical Trials Register). This investigation was approved by the local Ethics Committee (No. 10-121-0263). All procedures were in accordance with the ethical standards of the responsible committee on human experimentation and with the Declaration of Helsinki of 1975, as revised in 2000. The study collective including 3D CT of all patients was anonymized using numbers.

Informed consent

Informed consent was obtained from all individual participants included in the study.

Supplementary material

402_2018_2931_MOESM1_ESM.xlsx (1.2 mb)
Supplementary material 1 (XLSX 1261 KB)
402_2018_2931_MOESM2_ESM.jpg (6.5 mb)
Supplementary material 2 (JPG 6657 KB)
402_2018_2931_MOESM3_ESM.jpg (6.7 mb)
Supplementary material 3 (JPG 6864 KB)


  1. 1.
    Benditz A, Boluki D, Weber M et al (2017) Comparison of Lumbar Lordosis in Lateral Radiographs in Standing Position with supine MR Imaging in consideration of the Sacral Slope (Vergleich der lumbalen Lordose im seitlichen Rontgenbild im Stehen und der MRT unter besonderer Berucksichtigung des “Sacral Slope”). Rofo 189(3):233–239. PubMedCrossRefGoogle Scholar
  2. 2.
    Roussouly P, Gollogly S, Berthonnaud E et al (2005) Classification of the normal variation in the sagittal alignment of the human lumbar spine and pelvis in the standing position. Spine (Phila Pa 1976) 30(3):346–353CrossRefGoogle Scholar
  3. 3.
    Labelle H, Mac-Thiong J-M, Roussouly P (2011) Spino-pelvic sagittal balance of spondylolisthesis: a review and classification. Eur Spine J 20 Suppl 5: 641–646.
  4. 4.
    Craiovan B, Weber M, Worlicek M et al (2016) Measuring acetabular cup orientation on antero-posterior radiographs of the hip after total hip arthroplasty with a vector arithmetic radiological method. Is it valid and verified for daily clinical practice? (Messung der Huftpfannenposition auf anteroposterioren Beckenubersichtsaufnahmen nach Implantation einer Huftendtotalendoprothese mittels vektor-arithmetischer Methode. Wie genau ist dies im klinischen Alltag?) Rofo 188(6):574–581. CrossRefPubMedGoogle Scholar
  5. 5.
    Wan Z, Malik A, Jaramaz B et al (2009) Imaging and navigation measurement of acetabular component position in THA. Clin Orthop Relat Res 467(1):32–42. CrossRefPubMedGoogle Scholar
  6. 6.
    Lembeck B, Mueller O, Reize P et al (2005) Pelvic tilt makes acetabular cup navigation inaccurate. Acta Orthop 76(4):517–523. CrossRefPubMedGoogle Scholar
  7. 7.
    Malik A, Wan Z, Jaramaz B et al (2010) A validation model for measurement of acetabular component position. J Arthroplasty 25(5):812–819. CrossRefPubMedGoogle Scholar
  8. 8.
    Schwarz TJ, Weber M, Dornia C et al (2017) Correction of pelvic tilt and pelvic rotation in cup measurement after THA—an experimental study (Korrektur der Beckenverkippung und der Beckenverdrehung bei der Pfannenmessung nach Huft-TEP-Versorgungen - Eine experimentelle Studie). Rofo 189(9):864–873. CrossRefPubMedGoogle Scholar
  9. 9.
    Tannast M, Fritsch S, Zheng G et al (2015) Which radiographic hip parameters do not have to be corrected for pelvic rotation and tilt? Clin Orthop Relat Res 473(4):1255–1266. CrossRefPubMedGoogle Scholar
  10. 10.
    Legaye J, Duval-Beaupere G, Hecquet J et al (1998) Pelvic incidence: a fundamental pelvic parameter for three-dimensional regulation of spinal sagittal curves. Eur Spine J 7(2):99–103CrossRefPubMedPubMedCentralGoogle Scholar
  11. 11.
    Le Huec JC, Aunoble S, Philippe L et al (2011) Pelvic parameters: origin and significance. Eur Spine J 20 Suppl 5: 564–571.
  12. 12.
    Tannast M, Murphy SB, Langlotz F et al (2006) Estimation of pelvic tilt on anteroposterior X-rays—a comparison of six parameters. Skeletal Radiol 35(3):149–155. CrossRefPubMedGoogle Scholar
  13. 13.
    Renkawitz T, Weber M, Springorum HR et al (2015) Impingement-free range of movement, acetabular component cover and early clinical results comparing ‘femur-first’ navigation and ‘conventional’ minimally invasive total hip arthroplasty: a randomised controlled trial. Bone Joint J 97-B(7):890–898. CrossRefPubMedGoogle Scholar
  14. 14.
    Babisch JW, Layher F, Amiot LP (2008) The rationale for tilt-adjusted acetabular cup navigation. J Bone Joint Surg Am 90(2):357–365. CrossRefPubMedGoogle Scholar
  15. 15.
    Lewinnek GE, Lewis JL, Tarr R et al (1978) Dislocations after total hip-replacement arthroplasties. J Bone Joint Surg Am 60(2):217–220CrossRefPubMedGoogle Scholar
  16. 16.
    Marx A, Knoch M von, Pfortner J et al (2006) Misinterpretation of cup anteversion in total hip arthroplasty using planar radiography. Arch Orthop Trauma Surg 126(7):487–492. CrossRefPubMedGoogle Scholar
  17. 17.
    Craiovan B, Renkawitz T, Weber M et al (2014) Is the acetabular cup orientation after total hip arthroplasty on a two dimension or three dimension model accurate? Int Orthop 38(10):2009–2015. CrossRefPubMedGoogle Scholar
  18. 18.
    Blondel B, Schwab F, Patel A et al (2012) Sacro-femoral-pubic angle: a coronal parameter to estimate pelvic tilt. Eur Spine J 21(4):719–724. CrossRefPubMedGoogle Scholar
  19. 19.
    Vialle R, Levassor N, Rillardon L et al (2005) Radiographic analysis of the sagittal alignment and balance of the spine in asymptomatic subjects. J Bone Joint Surg Am 87(2):260–267. CrossRefPubMedGoogle Scholar
  20. 20.
    Pierrepont J, Hawdon G, Miles BP et al (2017) Variation in functional pelvic tilt in patients undergoing total hip arthroplasty. Bone Joint J 99-B(2): 184–191. CrossRefPubMedGoogle Scholar
  21. 21.
    Kanawade V, Dorr LD, Wan Z (2014) Predictability of acetabular component angular change with postural shift from standing to sitting position. J Bone Joint Surg Am 96(12):978–986. CrossRefPubMedGoogle Scholar
  22. 22.
    Henebry A, Gaskill T (2013) The effect of pelvic tilt on radiographic markers of acetabular coverage. Am J Sports Med 41(11):2599–2603. CrossRefPubMedGoogle Scholar
  23. 23.
    Monazzam S, Agashe M, Hosalkar HS (2013) Reliability of overcoverage parameters with varying morphologic pincer features: comparison of EOS(R) and radiography. Clin Orthop Relat Res 471(8):2578–2585. CrossRefPubMedPubMedCentralGoogle Scholar
  24. 24.
    Schwarz T, Weber M, Worner M et al (2017) Central X-ray beam correction of radiographic acetabular cup measurement after THA: an experimental study. Int J Comput Assist Radiol Surg 12(5):829–837. CrossRefPubMedGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of Orthopedic SurgeryUniversity Medical Center RegensburgBad AbbachGermany

Personalised recommendations