Association between thoracic inlet diameter ratio and clavicle fractures: A case-control study

Clavicle fractures account for 2-10 % of skeletal injuries, often resulting from lateral shoulder falls (87 % of cases), and are common in pediatric and young adult populations. Despite their clinical importance, the role of anatomical factors like thoracic inlet dimensions in fracture risk is poorly understood.

This STROBE-compliant case-control study evaluated the association between thoracic inlet measurements-anterior-posterior (AP) diameter, transverse diameter, and area-and clavicle fracture risk, with secondary analyses by age, sex, and BMI.

We studied 27 patients with clavicle fractures and 53 matched controls (aged 18-65 years) who underwent chest CT evaluation for suspected clavicle fracture following upper chest trauma but were confirmed to have no fracture; their CTs were then used for thoracic inlet measurements. Statistical analyses compared AP diameter, transverse diameter, and transverse/AP ratio between groups. The fracture group showed a significantly larger AP diameter (5. 80 ± 0.90 cm vs. 5. 34 ± 0.77 cm, p = 0.0181) and a significantly lower transverse/AP ratio (1. 88 ± 0.31 vs. 2. 08 ± 0.39, p = 0.025) than controls, suggesting a relatively broader, narrower inlet shape is associated with fractures. Transverse diameter (10. 68 ± 1.15 cm vs. 10. 85 ± 0.93 cm, p = 0.424) and inlet area (59. 15 ± 10.60 cm² vs. 57. 84 ± 9.34 cm², p = 0.5742) were similar between groups. Subgroup analyses indicated stronger differences in males (e.g., transverse/AP ratio: 1. 77 ± 0.33 vs. 2. 09 ± 0.40, p = 0.005) and those with BMI <23 kg/m ² (e.g., transverse/AP ratio: 1. 69 ± 0.39 vs. 2. 14 ± 0.42, p = 0.007).

We conclude that increased AP diameter and reduced transverse/AP ratio of the thoracic inlet may elevate clavicle fracture risk, highlighting anatomical influences on susceptibility. Further biomechanical and preventive studies are needed.