Background: There is no consensus regarding the optimal radiographic criteria for predicting the final healing of fractures. The purpose of this study was to determine if the time to the radiographic appearance of cortical bridging predicted the final healing of tibial shaft fractures, to examine the reliability of this assessment, and to determine when it is most accurate during the postoperative period.
Methods: We retrospectively reviewed the data on 176 tibial fractures (OTA [Orthopaedic Trauma Association] 42-A, B, and C) treated with intramedullary nailing at a level-I trauma center from 2007 through 2010. Postoperative radiographs were assessed for varying degrees of cortical bridging, and interobserver reliability was calculated. Receiver operating characteristic (ROC) curve and chi-square analyses determined the accuracy of cortical bridging assessments in predicting union.
Results: The nonunion rate was 7%. Any cortical bridging within four months was an excellent predictor of final healing (accuracy = 99%, area under the curve [AUC] = 0.995, p < 0.0001) and was the most reliable criterion (kappa = 0.90). All fractures that showed unicortical bridging eventually showed bridging of three cortices without additional intervention.
Conclusions: Assessment for any cortical bridging by four months postoperatively is a reliable, accurate predictor of tibial shaft fracture-healing. This relatively early radiographic finding discriminates between fractures that will undergo late union with observation alone and those destined for nonunion.
Level of Evidence: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.
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2Department of Orthopaedic Surgery-Trauma, Carolinas Medical Center, 1025 Morehead Medical Plaza, #300, P.O. Box 32861, Charlotte, NC 28204
3Orthopaedic Clinical Research (R.S.) and Department of Orthopaedic Surgery-Trauma (M.B.), Carolinas Medical Center,1320 Scott Avenue, P.O. Box 32861, Charlotte, NC 28204
4Department of Orthopaedic Surgery-Trauma, Carolinas Medical Center, 1000 Blythe Boulevard, Level 1, B-Wing, Room 1201, P.O. Box 32861, Charlotte, NC 28204