Session VII - Pelvis

Fri., 10/6/06 Pelvis, Paper #40, 3:48 pm

Computerized Tomographic-Generated Images Improve Diagnostic Accuracy in Acetabular Fractures and Are Adequate for Planning Surgical Approach

Garrick Cox, MD (*); Robert O'Toole, MD (*); K. Shanmuganathan, MD (*); Clifford Turen, MD (*); Marcus Sciadini, MD (*); Jason Nascone, MD (*);
R. Adams Cowley Shock Trauma Center, University of Maryland Medical School, Baltimore, Maryland, USA

Purpose: Axial computerized tomographic (CT) images have been reported to offer no advantage over plain radiographs for classifying acetabular fractures. Additional radiographic CT-generated modalities are now available; however, the influence of these studies on surgeons' diagnoses or planned approaches is not well characterized. Our hypothesis is that CT-generated images in comparison to plain films alone will improve the ability to classify the fracture and will be adequate for planning surgical approach.

Methods: We prospectively studied 96 consecutive patients with acetabular fractures between June 2005 and November 2005. Patients were excluded if all studies were unavailable, leaving 48 patients. Four different image sets for each individual patient were evaluated: (A) Judet radiographs plus axial CT, (B) plain Judet radiographs alone, (C) 3-dimensional CT reconstructions, and (D) CT-simulated Judet films. All patient identifiers were removed. The diagnosis and surgical approach was recorded for 192 image sets. Images were viewed in random order by four orthopaedic trauma fellowship-trained surgeons. The gold standard was determined by all 4 surgeons through a group consensus. Agreement between four imaging methods was evaluated using kappa statistics for multiple raters and nominal data.

Results: Comparing the gold standard diagnosis to the four imaging modalities, plain Judet radiographs had a worse kappa value than the CT-generated images (table below). The kappa values for all three CT-generated images approached 0.70. The kappa values for the surgical approach were not significantly influenced by the imaging modality.

Kappa Values Comparing Each Imaging Modality
   Method A  Method B  Method C  Method D
 Diagnosis   0.701  0.481* 0.664  0.692
 Surgical Approach  0.692  0.594  0.629  0.673
*P <0.05, all other values NS

Conclusion/Significance: The accuracy of plain radiographs alone was worse than CT-generated images in terms of diagnosis, questioning the utility of plain films for diagnosis. All four modalities were equal at predicting surgical approach, also arguing that newer CT-generated images are as useful as plain radiographs at guiding surgical approach.

If noted, the author indicates something of value received. The codes are identified as a-research or institutional support; b-miscellaneous funding; c-royalties; d-stock options; e-consultant or employee; n-no conflicts disclosed, and *disclosure not available at time of printing.
· The FDA has not cleared this drug and/or medical device for the use described in this presentation (i.e., the drug or medical device is being discussed for an "off label" use). · · FDA information not available at time of printing.