J.B. Gill, T. Risko, V. Raducan, J.S. Grimes, and R.C. Schutt Jr. reply:
We stand by our conclusion that gravity stress radiographs are equivalent to manual stress radiographs for determining deltoid ligament injury in association with an isolated fibular fracture. In order to further clarify this, we reviewed radiographs after the initial study end point (up to October 2007). There were an additional eight supination-external rotation (SER) type-II fractures and nineteen SER type-IV fractures with adequate radiographs. Medial clear space measurements were again made with use of the same PACS (Picture Archiving and Communications System). These results were then added to the previously published results.
The average medial clear space was 3.93 mm (standard deviation, 0.68 mm) for SER type-II injuries compared with 6.48 mm (standard deviation, 2.23 mm) for SER type-IV injuries (p < 0.000001). A post hoc power analysis was performed and showed that these results were adequately powered. No patient in whom an SER type-II injury had been managed nonoperatively showed any widening of the medial clear space during the follow-up period. We have used this protocol successfully at our teaching institution for three years. We have found it easy to administer and reliable in correctly diagnosing stable or unstable SER-type fractures.
We understand the point that Dr. Carney and Dr. Kuhn bring up, and we hope that these additional data adequately answer their questions. We appreciate other colleagues' critical evaluation of our study and results, as this dialogue furthers the understanding of this topic. Moreover, a continual peer review ensures that the "science" behind the study is appropriate and valid.
These letters originally appeared, in slightly different form, on . They are still available on the web site in conjunction with the article to which they refer.