Accuracy of detecting screw penetration of the acetabulum with intraoperative fluoroscopy and computed tomography

Citation
Db. Carmack et al., Accuracy of detecting screw penetration of the acetabulum with intraoperative fluoroscopy and computed tomography, J BONE-AM V, 83A(9), 2001, pp. 1370-1375
Citations number
12
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Ortopedics, Rehabilitation & Sport Medicine","da verificare
Journal title
JOURNAL OF BONE AND JOINT SURGERY-AMERICAN VOLUME
ISSN journal
0021-9355 → ACNP
Volume
83A
Issue
9
Year of publication
2001
Pages
1370 - 1375
Database
ISI
SICI code
0021-9355(200109)83A:9<1370:AODSPO>2.0.ZU;2-V
Abstract
Background: The purpose of this study was to determine the accuracy of comp uted tomography and fluoroscopy in assessing joint penetration by periaceta bular screws. Methods: A 3.5-mm acetabular periarticular screw was inserted in each of th irty-nine cadaveric hemipelves. Twenty screws were intentionally directed t o violate the articular surface, whereas nineteen screws were positioned to avoid the articular surface. Using two fluoroscopic views (tangential and axial) in a manner simulating the clinical setting, an examiner blinded to the actual screw location determined whether each screw was violating the a rticular surface. In addition, each hemipelvis was examined with computed t omography with use of two different techniques: (1) a 1-mm slice thickness at 1-mm intervals, and (2) a 4-mm slice thickness at 3-mm intervals. Each s can was evaluated by another examiner who was blinded to the actual screw l ocation. Sensitivity, specificity, and percent correct interpretations were then calculated for each method. Results: The sensitivity, specificity, and percent correct interpretations were 95%, 84%, and 90%, respectively, for axial fluoroscopy; 85%, 89%, and 87% for tangential fluoroscopy; 100%, 84%, and 92% for the computed tomogra phy scans with a 1-mm slice thickness at 1-mm intervals; and 100%, 58%, and 79% for the computed tomography scans with a 4-mm slice thickness at 3-mm intervals. Tangential fluoroscopy was found to be more specific than the co mputed tomography scans with a 4-mm slice thickness at 3-mm intervals (p = 0.02). No other significant differences were found. Conclusions: Fluoroscopy and computed tomography are equally accurate for d etermining intra-articular screw penetration. Computed tomography scans wit h thick slices (4 mm at 3-mm intervals) have a low specificity. Their use p ostoperatively may lead to a false-positive interpretation of the scan and unnecessary exploration of a hip for screw penetration. Clinical Relevance: Both intraoperative fluoroscopy and postoperative compu ted tomography are accurate methods for evaluating intra-articular screw pe netration. If postoperative computed tomography is used, 1-mm slices at 1-m m intervals should be chosen. Fluoroscopy has the advantage of enabling int raoperative diagnosis.