Radiographic rib fracture nonunion and association with fracture classification in adults with multiple rib fractures without flail segment: A multicenter prospective cohort study.

BACKGROUND: Rib fracture nonunion is a probable cause of chronic pain following chest trauma, although its prevalence remains unknown. The aims of this study were to determine rib fracture nonunion prevalence following nonoperative management and to determine if presence of nonunion was associated with the number of rib fractures, or the rib fracture classification of anatomical location, type, and displacement.

METHODS: This multicenter prospective cohort study included trauma patients with three or more fractured ribs but without a flail segment, who participated in the nonoperative management group of the FixCon trial between January 2019 and June 2022. The number and classification of rib fractures were assessed on trauma chest CT. Chest CTs conducted six months post-trauma were evaluated for the presence of nonunion. Radiological characteristics of nonunions were compared with normally healed rib fractures using the Mann-Whitney U, χ2 test, and Fisher's exact test as appropriate. A generalized linear model adjusted for multiple observations per patient when assessing the associations between nonunion and fracture characteristics.

RESULTS: A total of 68 patients were included with 561 post-traumatic fractures in 429 ribs. Chest CT after six months revealed nonunions in 67 (12 %) rib fractures in 29 (43 %) patients with a median of 2 (P25 -P75 1-3) nonunions per patient. Nonunion was most commonly observed in ribs seven to 10 (20-23 %, p < 0.001, adjusted p = 0.006). Nonunion occurred in 14 (5 %) undisplaced, 22 (19 %) offset, and 20 (23 %) displaced rib fractures (p < 0.001). No statistically significant association between rib fracture type and nonunion was found.

CONCLUSIONS: Forty-three percent of patients with multiple rib fractures had radiographic nonunion six months after trauma. Fractures in ribs seven to 10 and dislocated fractures had an increased risk of rib fracture nonunion.