Nonoperative treatment of humeral shaft fractures revisited.

Purpose: The purpose of this study was to examine the union rate of humeral shaft fractures treated nonoperatively and to establish whether a particular fracture type is more likely to go on to nonunion.

Methods: Radiographs and patient records of 207 humeral shaft fractures occurring during 5 years were retrospectively reviewed. All patients were initially managed nonoperatively and placed in a U-slab on diagnosis in the emergency department; this was converted to a functional humeral brace at 7 to 10 days after injury. Fracture location, morphology and comminution were assessed radiologically. Union was defined as the absence of pain and movement at the fracture site in the presence of radiographic callus formation. Nonunion was defined as no evidence of bone union by 1 year after injury or fractures requiring delayed fixation, defined as operative fixation undertaken more than 6 weeks after injury.

Results: The study included 138 humeral shaft fracture patients; 18 patients (11%) were lost to follow-up, and 24 went on to nonunion, giving an overall union rate of 83%. Of the 24 nonunions, 15 underwent delayed operative fixation at an average of 8.3 months after injury. The union rate for proximal-third fractures was 76% compared with 88% for middle-third fractures and 85% for distal-third fractures. Comminuted fractures (defined as 3+ parts) had a 89% union rate regardless of position.

Conclusion: A lower threshold for surgical intervention may be considered in proximal-third, two-part spiral-oblique humeral shaft fractures. Brace therapy can be the optimal treatment regimen, but it is not the only option.