OBJECTIVES

Intramedullary nailing (IMN) is a widely used method for treating tibial fractures. New injury severity score (NISS), a measure of trauma severity, has been used to predict mortality. This study evaluated NISS as an independent predictor for treatment with an intramedullary fixation in tibial fractures.

METHODS

This retrospective cohort study used patient-level data from the IBM® Marketscan® Commercial database. All patients between 18-64 years with tibial fractures between 2007-2018 who either underwent fixation with an IMN or did not receive any surgical procedure within three-months of tibial fracture were included. Mean (standard deviation, SD) NISS for the patients with and without IMN was reported. NISS was then categorized into three groups for easier clinical decision making based on the frequency distribution. A multivariable logistic regression was developed to evaluate categories of NISS as independent predictors for treatment with an IMN surgery controlling for demographic and clinical factors.

RESULTS

A total of 20,997 patients (Mean age, 38.8 years, 41.8% female, 39.2% with Elixhauser score >0) were included in the analysis. Mean (SD) NISS was 14.9 (7.2) for IMN group while it was 11.6 (8.9) for no surgery group. As the NISS score increased the mean hospital length of stay (LOS) was longer. For the NISS groups 1-8 and 9-16, the LOS was 4.9 days while for 17-75 group, the LOS was 8.2 days. Adjusted logistic model (c-statistic-0.90) showed that the patients in higher NISS group have statistically significantly higher odds (odds ratio, OR- 1.8 for 9-16 vs 1-8, OR- 1.2 for 17-75 vs 1-8, All P<0.05) for treatment with an intramedullary fixation as compared with lowest NISS group. Other significant factors included age, open fractures, shaft fractures and lower end fractures of tibia.

CONCLUSIONS

This study found that NISS is an independent predictor for treatment with an intramedullary fixation in tibial fractures.