Chest wall soft tissue thickness is associated with humeral shaft nonunion: a radiographic study

Alex, Choudhary, Kizzie Peters, Henry Colaco, Iain MacLeod

Hampshire Hospitals NHS Foundation Trust

Anecdotally, pendulous 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.

To produce radiographic measurements of chest wall soft tissue thickness and determine association with nonunion and angulation in diaphyseal humerus fractures.

217 patients who underwent conservative management for a diaphyseal humeral fracture were identified retrospectively from 2008-2017. Radiographic chest wall soft tissue thickness (STT) measurements were taken at three standardised points (upper, middle and lower) using a simple reproducible method. Ratios were also derived, dividing these figures by the mid-humerus diameter. Bivariate and multivariate analysis was used to assess association with nonunion.

There were 58 (26.7%) cases of nonunion. On multivariate analysis, the middle (OR 1.39, 95% p<0.001) and lower (OR 1.23, p=0.009) STT measurements were independently associated with nonunion. Additionally, the middle (OR 1.85, p<0.001), lower (OR 1.47, p=0.005) and maximum (OR 1.40, p<0.001) STT ratios were independently associated with nonunion. A receiver operating characteristic curve was used to determine threshold values for middle STT of 6.2cm (sensitivity 62.1%, specificity 61.6%) and middle STT ratio of 3.0 (sensitivity 69.0%, specificity 62.3%). A middle STT of ≥6.2cm (OR 2.68, p=0.004) and a middle STT ratio of ≥3.0 (OR 3.73, p<0.001) were each independently predictive of nonunion.

Chest wall soft tissue thickness is independently associated with humeral shaft nonunion. A middle STT ratio of ≥3 was predictive of nonunion. Threshold values can assist in decision making for these fractures.