Abstract
Background
Acetabular fracture diagnosis is traditionally made with AP and oblique pelvic plain radiographs. Obesity may impair diagnostic accuracy of plain radiographs. New CT reconstruction algorithms allow for simulated radiographs that may eliminate the adverse imaging effects of obesity.
Questions/purposes
In obese patients with acetabular fractures, we compared CT-generated and plain radiographs in terms of (1) ability to classify fracture type, (2) agreement in fracture classification, and (3) surgeon performance at different experience levels.
Methods
CT-generated and plain radiograph image sets were created for 16 obese (BMI > 35) patients with 17 acetabular fractures presenting from 2009 to 2011. Three orthopaedic trauma attending physicians, three senior residents, and three junior residents independently viewed these sets and recorded their diagnoses. These diagnoses were compared to the postoperative findings, which we defined as the gold standard for diagnosis. To assess intraobserver reliability, the same observers reviewed a rerandomized set 1 month later. We had 80% power to detect a 25% difference in the percentage of correctly classified fractures based on a post hoc sample size calculation and 80% power to detect a 0.10 difference in κ value based on both a priori and post hoc sample size calculations.
Results
With the numbers available (153 observations in each image set, 51 for each of the three observer groups), we found no differences between CT-generated and plain radiographs, respectively, in terms of percentage of correct diagnoses for the observer groups (all observers: 54% versus 49%, p = 0.48; attendings: 61% versus 59%, p = 0.83; senior residents: 51% versus 53%, p = 0.84; and junior residents: 49% versus 35%, p = 0.16). Furthermore, agreement between CT-generated and plain radiographic fracture classifications was substantial (κ = 0.67). Nonetheless, the attending and senior resident groups performed better in correctly classifying the fracture than the junior residents when using plain radiographs (p = 0.01 and p = 0.049, respectively). Performance was not different when comparing the attendings to the senior resident and junior groups or comparing the senior residents to the junior residents using CT-generated radiographs (p = 0.32, p = 0.22, and p = 0.83, respectively).
Conclusions
CT-generated radiographs are as good as plain radiographs for experienced surgeons for classifying acetabular fractures in obese patients. CT-generated imaging may be valuable in both teaching and clinical settings, and it may spare the patient additional radiation exposure and discomfort.
Level of Evidence
Level II, diagnostic study. See the Instructions for Authors for a complete description of levels of evidence.
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References
Beaule PE, Dorey FJ, Matta JM. Letournel classification for acetabular fractures: assessment of interobserver and intraobserver reliability. J Bone Joint Surg Am. 2003;85:1704–1709.
Borrelli J Jr, Peelle M, McFarland E, Evanoff B, Ricci WM. Computer-generated radiographs are as good as plain radiographs for assessment of acetabular fractures. Am J Orthop. 2008;37:455–4603.
Centers for Disease Control and Prevention. Overweight and obesity. Available at: http://www.cdc.gov/obesity/data/adult.html. Accessed November 28, 2013.
Court-Brown CM, Aitken SA, Forward D, O’Toole RV 3rd. The epidemiology of fractures. In: Bucholz RW, Heckman JD, Court-Brown CM, Tornetta P 3rd, eds. Rockwood and Green’s Fractures in Adults. 7th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2009:1463–1523.
Faul F, Erdfelder E, Lang AG, Buchner A. G*Power 3: a flexible statistical power analysis program for the social, behavioral, and biomedical sciences. Behav Res Methods. 2007;39:175–191.
Judet R, Judet J, Letournel E. Fractures of the acetabulum: classification and surgical approaches for open reduction. J Bone Joint Surg Am. 1964;46:1615–1638.
Kuszyk BS, Heath DG, Bliss DF, Fishman EK. Skeletal 3-D CT: advantages of volume rendering over surface rendering. Skeletal Radiol. 1996;25:207–214.
Laird A, Keating JF. Acetabular fractures: a 16 year prospective epidemiological study. J Bone Joint Surg Br. 2005;87:969–973.
Landis JR, Koch GG. The measurement of observer agreement for categorical data. Biometrics. 1977;33:159–174.
Letournel E, Judet R. Fractures of the Acetabulum. 2nd ed. New York, NY: Springer; 1993.
Ly TV, Stover MD, Sims SH, Reilly MC. The use of an algorithm for classifying acetabular fractures. Clin Orthop Relat Res. 2011;469:2371–2376.
Marsh JL, Slongo TF, Agel J, Broderick JS, Creevey W, De Coster TA, Prokuski L, Sirkin MS, Ziran B, Henley B, Audige L. Fracture and dislocation classification compendium-2007: Orthopaedic Trauma Association classification, database and outcomes committee. J Orthop Trauma. 2007;21(suppl 10):S1–S133.
Martinez CR, Di Pasquale TG, Helfet DL, Graham AW, Sanders RW, Ray LD. Evaluation of acetabular fractures with two- and three-dimensional CT. Radiographics. 1992;12:227–242.
Norman GR, Streiner DL. Biostatistics: The Bare Essentials. 2nd ed. London, UK: BC Decker, Inc; 2000.
Ohashi K, El-Khoury GY, Abu-Zahra KW, Berbaum KS. Interobserver agreement for Letournel acetabular fracture classification with multidetector CT: are standard Judet radiographs necessary? Radiology. 2006;241:386–391.
O’Toole RV, Cox G, Shanmuganathan K, Castillo RC, Turen CH, Sciadini MF, Nascone JW. Evaluation of computed tomography for determining the diagnosis of acetabular fracture. J Orthop Trauma. 2010;24:284–290.
Porter SE, Russell GV, Dews RC, Qin Z, Woodall J Jr, Graves M. Complications of acetabular fracture surgery in morbidly obese patients. J Orthop Trauma. 2008;22:589–594.
Routt ML Jr, Agarwal A. Acetabular fractures: definitive treatment and expected outcomes. In: Teague D, Schmidt A, eds. Orthopaedic Knowledge Update: Trauma 4. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2010:323–335.
Scott WW, Fishman EK, Magid D. Acetabular fractures: optimal imaging. Radiology. 1987;165: 537–539.
Sim J, Wright CC. The kappa statistic in reliability studies: use, interpretation, and sample size requirements. Phys Ther. 2005;85:257–268.
Sturm R. Increases in morbid obesity in the USA: 2000–2005. Public Health. 2007;121:492–496.
World Health Organization. BMI classification. Available at: http://apps.who.int/bmi/index.jsp?introPage=intro_3.html. Accessed November 28, 2013.
Acknowledgments
We thank Todd Gebke BSRT for his assistance in obtaining the CT-generated images and Heidi Israel PhD and Eric S. Armbrecht PhD for their help with the statistical analyses.
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Each author certifies that he or she, or a member of his or her immediate family, 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.
All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research ® editors and board members are on file with the publication and can be viewed on request.
Each author certifies that his or her institution approved the human protocol for this investigation and that all investigations were conducted in conformity with ethical principles of research.
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Sinatra, P.M., Moed, B.R. CT-generated Radiographs in Obese Patients With Acetabular Fractures: Can They Be Used in Lieu of Plain Radiographs?. Clin Orthop Relat Res 472, 3362–3369 (2014). https://doi.org/10.1007/s11999-014-3697-4
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DOI: https://doi.org/10.1007/s11999-014-3697-4