Session IV - Basic Science

Fri., 10/11/13 Basic Science, PAPER #56, 1:46 pm OTA 2013

Any Cortical Bridging Predicts Healing of Tibial Shaft Fractures

William Lack, MD; James Starman, MD; Rachel Seymour, PhD; Michael J. Bosse, MD;
Madhav Karunakar, MD; Stephen Sims, MD; James Kellam, MD
Carolinas Medical Center, Charlotte, North Carolina, USA

Background/Purpose: There is no consensus regarding the optimal radiographic criteria for predicting the final healing of fractures or when these criteria should be employed. Given that healing occurs over time, the accuracy of radiographic criteria for predicting union is time-dependent. The purpose of this study was to determine the accuracy of unicortical, bicortical, and tricortical bridging in predicting the final healing of tibial shaft fractures treated with intramedullary nailing and to determine when these assessments are most accurate during the postoperative period.

Methods: A retrospective review at a Level I trauma center identified 176 tibia fractures (OTA 42-A,B,C) treated with intramedullary nailing over a 3-year period. All postoperative digital radiographs were assessed for the presence of varying degrees of cortical bridging. Receiver operating curve (ROC) and χ2 analyses determined the accuracy of predicting union by assessing for the degree of radiographic cortical bridging at various postoperative time points.

Results: The nonunion rate was 7.4% (13 of 176 fractures). Any cortical bridging by 4 months postoperatively was an excellent predictor of final healing (accurate in 174 of 176 fractures, ROC curve area 0.995, P <0.0001) and was the most reliable criterion (kappa 0.90). All fractures bridging a single cortex within the first 4 months eventually bridge three cortices with observation alone. Bridging of additional cortices did not improve the predictive accuracy (ROC curve area 0.975 and 0.990 for bridging of two and three cortices, respectively, P <0.0001 for both). Additionally, these more stringent criteria were not accurate until 7 months for two cortices and 12 months for three cortices and were less reliable (kappa 0.74 for two cortices and 0.78 for three cortices).

Conclusion: Assessment for any cortical bridging by 4 months postoperatively accurately predicts final healing of tibial shaft fractures and has a high reliability. This relatively early radiographic finding discriminates between fractures achieving late union with observation alone and those destined to nonunion. Requiring additional cortices to be bridged does not add predictive value and risks overestimation of the nonunion rate. Assessment for any cortical bridging at 4months may guide early intervention in appropriate patients while avoiding unnecessary surgery in others.

Alphabetical Disclosure Listing

• 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. Δ OTA Grant.