Chest wall soft tissue thickness is associated with humeral shaft non-union: A radiographic study

Abstract

Background Anecdotally, upper truncal obesity and large breasts have often been associated with inferior outcomes from non-operative management of diaphyseal humerus fractures. However, this assertion is without basis in the literature. Aims To produce radiographic measurements of chest wall soft tissue thickness (STT) and determine association with non-union in diaphyseal humerus fractures. Methods Two hundred and seventeen consecutive non-operative humeral shaft fractures were included. Radiographic STT measurements were taken at three standardised points (upper, middle and lower) using a simple reproducible method, with ratios derived (dividing these figures by the mid-humerus diameter). Bivariate and multivariable analyses were used to assess association with non-union. Results There were 58 (26.7%) cases of non-union. On multivariable analysis, the middle (odds ratio (OR) 1.39, p <  0.001) and lower (OR 1.23, p = 0.009) STT measurements were independently associated with non-union. Additionally, the middle (OR 1.85, p < 0.001) and lower (OR 1.47, p < 0.001) STT ratios were independently associated with non-union. A receiver operating characteristic curve determined a threshold value of a middle STT ratio of ≥ 3 (OR 3.73, p < 0.001, sensitivity 69.0%, specificity 62.3%), which was independently associated with non-union. Conclusion Chest wall STT is independently associated with humeral shaft non-union. Threshold values can assist in decision making for these fractures.