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Methods for Assessing Leg Length Discrepancy

Abstract

The use of accurate and reliable clinical and imaging modalities for quantifying leg-length discrepancy (LLD) is vital for planning appropriate treatment. While there are several methods for assessing LLD, we questioned how these compared. We therefore evaluated the reliability and accuracy of the different methods and explored the advantages and limitations of each method. Based on a systematic literature search, we identified 42 articles dealing with various assessment tools for measuring LLD. Clinical methods such as use of a tape measure and standing blocks were noted as useful screening tools, but not as accurate as imaging modalities. While several studies noted that the scanogram provided reliable measurements with minimal magnification, a full-length standing AP computed radiograph (teleoroentgenogram) is a more comprehensive assessment technique, with similar costs at less radiation exposure. We recommend use of a CT scanogram, especially the lateral scout view in patients with flexion deformities at the knee. Newer modalities such as MRI are promising but need further investigation before being routinely employed for assessment of LLD.

Level of Evidence: Level IV, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

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References

  1. Aaron A, Weinstein D, Thickman D, Eilert R. Comparison of orthoroentgenography and computed tomography in the measurement of limb-length discrepancy. J Bone Joint Surg Am. 1992;74:897–902.

    PubMed  CAS  Google Scholar 

  2. Aitken GF, Flodmark O, Newman DE, Kilcoyne RF, Shuman WP. Mack LA. Leg length determination by CT digital radiography. AJR Am J Roentgenol. 1985;144:613–615.

    PubMed  CAS  Google Scholar 

  3. Altongy JF, Harcke HT, Bowen JR. Measurement of leg length inequalities by Micro-Dose digital radiographs. J Pediatr Orthop. 1987;7:311–316.

    PubMed  CAS  Google Scholar 

  4. Aspegren DD, Cox JM, Trier KK. Short leg correction: a clinical trial of radiographic vs. non-radiographic procedures. J Manipulative Physiol Ther. 1987;10:232–238.

    PubMed  CAS  Google Scholar 

  5. Badii M, Shin S, Torreggiani WC, Jankovic B, Gustafson P, Munk PL, Esdaile JM. Pelvic bone asymmetry in 323 study participants receiving abdominal CT scans. Spine. 2003;28:1335–1339.

    PubMed  Article  Google Scholar 

  6. Baylis WJ, Rzonca EC. Functional and structural limb length discrepancies: evaluation and treatment. Clin Podiatr Med Surg. 1988;5:509–520.

    PubMed  CAS  Google Scholar 

  7. Beattie P, Isaacson K, Riddle DL, Rothstein JM. Validity of derived measurements of leg-length differences obtained by use of a tape measure. Phys Ther. 1990;70:150–157.

    PubMed  CAS  Google Scholar 

  8. Cleveland RH, Kushner DC, Ogden MC, Herman TE, Kermond W, Correia JA. Determination of leg length discrepancy. A comparison of weight-bearing and supine imaging. Invest Radiol. 1988;23:301–304.

    PubMed  Article  CAS  Google Scholar 

  9. Defrin R, Ben Benyamin S, Aldubi RD, Pick CG. Conservative correction of leg-length discrepancies of 10 mm or less for the relief of chronic low back pain. Arch Phys Med Rehabil. 2005;86:2075–2080.

    PubMed  Article  Google Scholar 

  10. Fisk JW, Baigent ML. Clinical and radiological assessment of leg length. N Z Med J. 1975;81:477–480.

    PubMed  CAS  Google Scholar 

  11. French SD, Green S, Forbes A. Reliability of chiropractic methods commonly used to detect manipulable lesions in patients with chronic low-back pain. J Manipulative Physiol Ther. 2000;23:231–238.

    PubMed  Article  CAS  Google Scholar 

  12. Glass RB, Poznanski AK. Leg-length determination with biplanar CT scanograms. Radiology. 1985;156:833–834.

    PubMed  CAS  Google Scholar 

  13. Green WT, Wyatt GM, Anderson M. Orthoroentgenography as a method of measuring the bones of the lower extremities. J Bone Joint Surg Am. 1946;28:60–65.

    Google Scholar 

  14. Gurney B. Leg length discrepancy. Gait Posture. 2002;15:195–206.

    PubMed  Article  Google Scholar 

  15. Hanada E, Kirby RL, Mitchell M, Swuste JM. Measuring leg-length discrepancy by the “iliac crest palpation and book correction” method: reliability and validity. Arch Phys Med Rehabil. 2001;82:938–942.

    PubMed  Article  CAS  Google Scholar 

  16. Harris I, Hatfield A, Walton J. Assessing leg length discrepancy after femoral fracture: clinical examination or computed tomography? ANZ J Surg. 2005;75:319–321.

    PubMed  Article  Google Scholar 

  17. Helms CA, McCarthy S. CT scanograms for measuring leg length discrepancy. Radiology. 1984;151:802.

    PubMed  CAS  Google Scholar 

  18. Horsfield D, Jones SN. Assessment of inequality in length of the lower limb. Radiography. 1986;52:223–227.

    PubMed  CAS  Google Scholar 

  19. Huurman WW, Jacobsen FS, Anderson JC, Chu WK. Limb-length discrepancy measured with computerized axial tomographic equipment. J Bone Joint Surg Am. 1987;69:699–705.

    PubMed  CAS  Google Scholar 

  20. Jonson SR, Gross MT. Intraexaminer reliability, interexaminer reliability, and mean values for nine lower extremity skeletal measures in healthy naval midshipmen. J Orthop Sports Phys Ther. 1997;25:253–263.

    PubMed  CAS  Google Scholar 

  21. Kogutt MS. Computed radiographic imaging: use in low-dose leg length radiography. AJR Am J Roentgenol. 1987;148:1205–1206.

    PubMed  CAS  Google Scholar 

  22. Konermann W, Gruber G. Ultrasound determination of leg length [in German]. Orthopade. 2002;31:300–305.

    PubMed  Article  CAS  Google Scholar 

  23. Krettek C, Koch T, Henzler D, Blauth M, Hoffmann R. A new procedure for determining leg length and leg length inequality using ultrasound. II: Comparison of ultrasound, teleradiography and 2 clinical procedures in 50 patients [in German]. Unfallchirurg. 1996;99:43–51.

    PubMed  CAS  Google Scholar 

  24. Lampe HI, Swierstra BA, Diepstraten AF. Measurement of limb length inequality. Comparison of clinical methods with orthoradiography in 190 children. Acta Orthop Scand. 1996;67:242–244.

    PubMed  CAS  Google Scholar 

  25. Leitzes AH, Potter HG, Amaral T, Marx RG, Lyman S, Widman RF. Reliability and accuracy of MRI scanogram in the evaluation of limb length discrepancy. J Pediatr Orthop. 2005;25:747–749.

    PubMed  Article  Google Scholar 

  26. Machen MS, Stevens PM. Should full-length standing anteroposterior radiographs replace the scanogram for measurement of limb length discrepancy? J Pediatr Orthop B. 2005;14:30–37.

    PubMed  Google Scholar 

  27. Merrill OE. A method for the roentgen measurement of the long bones. Am J Roentgenol Radium Ther Nucl Med. 1942;48:405–406.

    Google Scholar 

  28. Millwee RH. Slit scanography. Radiology. 1937;28:483–486.

    Google Scholar 

  29. Moseley CF. Leg length discrepancy. In: Morrissy RT, Weinstein SL, eds. Lovell and Winter’s Pediatric Orthopedics. Philadelphia, PA: Lippincott Williams & Wilkins; 2006;1213–1256.

  30. Okun SJ, Morgan JW Jr, Burns MJ. Limb length discrepancy: a new method of measurement and its clinical significance. J Am Podiatry Assoc. 1982;72:595–599.

    PubMed  CAS  Google Scholar 

  31. Petrone MR, Guinn J, Reddin A, Sutlive TG, Flynn TW, Garber MP. The accuracy of the Palpation Meter (PALM) for measuring pelvic crest height difference and leg length discrepancy. J Orthop Sports Phys Ther. 2003;33:319–325.

    PubMed  Google Scholar 

  32. Porat S, Fields S. Limb length discrepancy determined by computerized tomography and radiography [in Hebrew]. Harefuah. 1989;116:515–516.

    PubMed  CAS  Google Scholar 

  33. Rhodes DW, Mansfield ER, Bishop PA, Smith JF. Comparison of leg length inequality measurement methods as estimators of the femur head height difference on standing Xray. J Manipulative Physiol Ther. 1995;18:448–452.

    PubMed  CAS  Google Scholar 

  34. Rhodes DW, Mansfield ER, Bishop PA, Smith JF. The validity of the prone leg check as an estimate of standing leg length inequality measured by Xray. J Manipulative Physiol Ther. 1995;18:343–346.

    PubMed  CAS  Google Scholar 

  35. Rondon CA, Gonzalez N, Agreda L, Millan A. Observer agreement in the measurement of leg length. Rev Invest Clin. 1992;44:85–89.

    PubMed  CAS  Google Scholar 

  36. Sabharwal S, Badarudeen S, McClemens E, Choung E. The effect of circular external fixation on limb alignment. J Pediatr Orthop. 2008;28:314–319.

    PubMed  Google Scholar 

  37. Sabharwal S, Zhao C, McKeon J, Melaghari T, Blacksin M, Wenekor C. Reliability analysis for radiographic measurement of limb length discrepancy: Full-length standing anteroposterior radiograph versus Scanogram. J Pediatr Orthop. 2007;27:46–50.

    PubMed  Google Scholar 

  38. Sabharwal S, Zhao C, McKeon JJ, McClemens E, Edgar M, Behrens F. Computed radiographic measurement of limb-length discrepancy. Full-length standing anteroposterior radiograph comared with scanogram. J Bone Joint Surg Am. 2006;88:2243–2251.

    PubMed  Article  Google Scholar 

  39. Saleh M, Milne A. Weight-bearing parallel-beam scanography for the measurement of leg length and joint alignment. J Bone Joint Surg Br. 1994;76:156–157.

    PubMed  CAS  Google Scholar 

  40. Shapiro F. Pediatric Orthopedic Deformities. Basic Science, Diagnosis, and Treatment. San Diego, CA: Academic Press; 2001;606–732.

  41. Temme JB, Chu WK, Anderson JC. CT scanograms compared with conventional orthoroentgenograms in long bone measurement. Radiol Technol. 1987;59:65–68.

    PubMed  CAS  Google Scholar 

  42. Terjesen T, Benum P, Rossvoll I, Svenningsen S, Floystad Isern AE, Nordbo T. Leg-length discrepancy measured by ultrasonography. Acta Orthop Scand. 1991;62:121–124.

    PubMed  CAS  Article  Google Scholar 

  43. Terry MA, Winell JJ, Green DW, Schneider R, Peterson M, Marx RG, Widmann RF. Measurement variance in limb length discrepancy: Clinical and radiographic assessment of interobserver and intraobserver variability. J Pediatr Orthop. 2005;25:197–201.

    PubMed  Article  Google Scholar 

  44. Tokarowski A, Piechota L, Wojciechowski P, Gajos L, Kusz D. Measurement of lower extremity length using computed tomography [in Polish]. Chir Narzadow Ruchu Ortop Pol. 1995;60:123–127.

    PubMed  CAS  Google Scholar 

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Acknowledgments

We thank Dr. Caixia Zhao and Ms. Emily McClemens, PA-C, for their assistance in preparing this manuscript.

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Correspondence to Sanjeev Sabharwal MD.

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Each author certifies that he or she has no commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article.

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Sabharwal, S., Kumar, A. Methods for Assessing Leg Length Discrepancy. Clin Orthop Relat Res 466, 2910–2922 (2008). https://doi.org/10.1007/s11999-008-0524-9

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Keywords

  • Intraclass Correlation Coefficient
  • Compute Radiography
  • Anterior Superior Iliac Spine
  • Medial Malleolus
  • Angular Deformity