To assess which fractures of the humeral diaphysis are prone to nonunion after functional bracing by analyzing patients that present for treatment of nonunion after brace treatment.
Thirty-two patients treated operatively for a nonunion of the diaphyseal humerus after functional brace treatment were analyzed with respect to the location and the pattern of the original fracture. There were 21 women and 11 men with an average age of 53 years (range 23–84 years).
The fracture involved the proximal third of the diaphysis in 17 patients, the middle third in 14 patients, and the distal third in 1 patient. The pattern of the fracture was oblique or spiral in 27 patients with a butterfly fragment in 11 of those patients. Only four patients had a transverse fracture. Operative fixation ultimately achieved union in all 32 patients, but a second procedure was necessary for loosening of fixation or persistent nonunion in 3 older-aged patients. The functional results were good or excellent in all 32 patients.
Compared with the epidemiology of acute diaphyseal humerus fractures, nonunions after functional bracing are more likely to follow spiral/oblique fractures that involve the mid- or proximal-third of the diaphysis. Operative treatment can gain union and improve arm function.