Lateral implosion injuries: Epidemiology, outcomes and evaluation of the Ch-Sh classification.

BACKGROUND

Lateral implosion injuries (LIIs) result from lateral trauma to the thoracic cage and shoulder, causing concomitant rib and shoulder girdle fractures. While individual combinations of rib and shoulder girdle fractures have been described, the clinical significance of LIIs is poorly understood. Current classification of LIIs relies on radiographic scores such as RibScore, which assess rib or shoulder fractures in isolation. The Ch-Sh (Chest-Shoulder) Classification was proposed to predict risk in LIIs, but its clinical validity has not been evaluated.

METHODS

A retrospective cohort study of patients admitted to a Major Trauma Centre in the UK with multiple rib fractures between 2010 and 2024. Patients were classified as LIIs or isolated rib fractures (IRFs) without additional shoulder injury. A validation cohort was established with patients stratified according to the original and a modified Ch-Sh Classification. Multivariable regression was used to assess associations of injury type (LII vs. IRF) and modified Ch-Sh score with outcomes. Discriminatory performance of a modified Ch-Sh Classification, RibScore, and a combined model was compared.

RESULTS

A total of 4145 patients met the inclusion criteria. Seven hundred eighty-two (18.9%) suffered LIIs, and 3363 (81.1%) suffered IRFs. LIIs were associated with increased hospital length of stay (p < 0.001), resource utilisation (p < 0.001), and adverse outcomes (p < 0.001). In the validation cohort (n = 539), higher Ch-Sh scores were associated with increased length of stay, resource utilisation, and adverse outcomes. The modified Ch-Sh Classification mostly demonstrated discriminatory ability comparable to RibScore, but Ch-Sh was superior for shoulder open reduction and internal fixation while RibScore was superior for SSRF. Discrimination significantly improved in the combined model.

CONCLUSIONS

LIIs represent a distinct injury pattern associated with increased morbidity and resource utilisation compared with IRFs. The Ch-Sh Classification demonstrated associations with outcomes and resource utilisation, suggesting that its use may improve risk stratification in LIIs. (J Trauma Acute Care Surg 2026;00:000-000 Copyright © 2026 Wolters Kluwer Health, LLC. All rights reserved.).

LEVEL OF EVIDENCE: Prognostic/Epidemiological; Level III.