A total of 67 humeral diaphyseal fractures treated with functional bracing was studied. The median follow-up was 30 weeks. Sixty-one fractures (91%) healed and 6 fractures (8.9%) progressed to non-unions. Fifty-four fractures could be functionally classified according to a modified Wasmer score. Pain, range of motion in the shoulder and elbow, and changes in activities of daily life were recorded. Loss of external rotation in the shoulder was most prominent, being present in 21 (38%) of the fractures. To evaluate the cause of loss of external rotation, 21 of the patients were selected for two groups to be studied with computed tomography (CT). Twelve patients had normal clinical findings without a loss of external rotation, while 9 patients had subnormal external rotation in the shoulder of the injured limb. Fracture consolidation in malrotation was seen frequently, and a linear correlation between the clinical loss of external rotation and CT findings was indicated, but no statistical agreement could be proved. The time between injury and brace application could possibly contribute to consolidation in malrotation.