Copyright © 2006 by The Journal of Bone and Joint Surgery, Inc.
Commentary & Perspective
Commentary & Perspective by
Thomas A. DeCoster, MD
Department of Orthopedics and Rehabilitation, University of New Mexico, Albuquerque, New Mexico
Bhattacharyya et al. are to be congratulated for giving practicing orthopaedists and trauma surgeons clinically useful information regarding the accuracy of computed tomography in the diagnosis of possible nonunion of tibial shaft fracture. They have convincingly shown that computed tomography is extremely sensitive but only moderately specific.
They have noted that when patients had symptoms suggestive of nonunion after treatment of tibial shaft fractures, the accuracy of detecting the presence of nonunion on plain film was less than 50% in this series. In such situations, computed tomography is commonly used to try to establish a diagnosis. Compared with similar articles in the literature, this article represents the best objective analysis of the accuracy of computed tomography in this situation.
The authors used the best available "gold standard" method to identify nonunion—the direct confirmation of the presence or absence of bone-healing at the time of surgery in patients who were managed operatively, or the six-month clinical course of patients who were managed nonoperatively. The results of an independent evaluation of the thirty-five patients are that the computed tomography criteria had 100% sensitivity (twenty-two of twenty-two patients with nonunion were identified with use of computed tomography) but only 62% specificity (clinical confirmation in only twenty-two of twenty-seven patients with computed tomography-diagnosed nonunion).
They demonstrate that computed tomography scan provides useful information despite the presence of artifact from internal fixation devices. The cost of this test appears warranted when the diagnosis of nonunion is in doubt. Patients with good outcomes and patients who clearly have a nonunion do not need computed tomography scans.
Interestingly, for at least two patients who had a nonunion according to the computed tomography scan, the treating surgeon proceeded with successful nonoperative treatment. This indicates the presence of variability in the assessment of computed tomography scans either among surgeons or between clinical practice and blinded review. An alternative explanation is that the computed tomographic criteria for nonunion as used in this study may be too lenient. Delayed unions may progress to complete union without surgical intervention.
I concur with the conclusion of the authors that computed tomography scans are useful when trying to determine whether or not a fracture of the tibial shaft is healed but that the surgeon should be cautious about overtreating delayed unions on the basis of the computed tomographic appearance alone.
*The author did not receive grants or outside funding in support of his research for or preparation of this manuscript. He did not receive payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, educational institution, or other charitable or nonprofit organization with which the author is affiliated or associated.
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