Introduction It is unknown whether the magnitude of rib fracture (RF) displacement predicts pain medication requirements in blunt chest trauma patients. Methods Adult blunt RF patients undergoing chest computed tomography (CT) admitted to an urban Level 1 trauma center (2007–2012) were retrospectively reviewed. Pain management in those with displaced RF (DRF), non-displaced RF (NDRF), or combined DRF and NDRF (CRF) was compared by univariate analysis. Linear regression models were developed to determine whether total opioids requirements [expressed as log morphine equianalgesic dose (MED)] could be predicted by the magnitude of RF displacement (expressed as the sum of the Euclidean distance of all displaced RF) or number of RF, after adjusting for patient and injury characteristics. Results There were 245 patients, of whom 39 (16%) had DRF only, 77 (31%) had NDRF only, and 129 (53%) had CRF. Opioids were given to 224 (91%) patients. Compared to DRF (mean1.7 RF/patient) and NDRF patients (2.4 RF/patient), those with CRF (6.8 RF/patient) were older and had more RF per patient and a higher ISS and MED (251 vs. 53 and 105 mg, respectively, p<0.0001 and p=0.0045). They also more frequently received patient controlled analgesia. DRF patients had a lower mean ISS and MED and received more epidural analgesia compared with patients with NDRF. Total MED was associated with both the magnitude of RF displacement (p<0.0001) and the number of RF (p<0.0001). Every 5 mm increase in total displacement predicted a 6.3% increase in mean MED (p=0.0035) while every additional RF predicted an 11.2% increase in MED (p=0.0001). These associations included adjustment for age, ISS, and presence of chest tubes. Conclusion The magnitude of RF displacement and the number of RF predicted opioids requirements. This information may assist in anticipating patients with blunt RF who might have higher analgesic requirements. Level of Evidence Prognostic study, level III.

Displacement patterns of rib fractures (RF) and their association with thoracic coinjuries and outcomes are unknown. This is a retrospective review of adult patients with blunt closed RF who underwent chest CT at a Level I trauma center (2007–2012). Displacement patterns of RF were compared among the three-dimensional planes using CT images. An analysis of receiver operating characteristic (ROC) curves was performed to identify displacements in each plane most strongly associated with chest coinjuries. Univariate analysis was used to find association of displaced RF with hospital course and outcome. There were 1127 RF (245 patients, most in ribs 3–9, 45 per cent displaced). Axial displacement was the most common, with odds ratios 7.20 and 2.13 compared with cranio-caudal, and impaction-separation (along rib axis) movement, respectively. Axial displacement thresholds performed well with hemothorax (2.8 mm, ROC = 0.74), pneumothorax (2.6 mm, ROC = 0.70), hemopneumothorax (3.1 mm, ROC = 0.77), flail chest (3.4 mm, ROC = 0.80), and chest tube placement (2.8 mm, ROC = 0.75). RF displacement was associated with increased days on mechanical ventilation and hospital length of stay. In conclusion, even minimal RF displacement is associated with increased risk of chest coinjuries and chest tube placement, and displacements correlated with increased days on mechanical ventilation and hospital length of stay. Future studies are required to investigate these associations, especially in relationship to the indications for rib plating.