Midshaft Humerus Fractures

Updated: Dec 01, 2020
  • Author: Matthew Lawless, MD; Chief Editor: Harris Gellman, MD  more...
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Practice Essentials

Fractures of the humeral shaft account for approximately 3% of all fractures. [1, 2]  These injuries are felt to occur in a bimodal distribution, often as the result of a fall in the elderly. [2]  Traditionally, humeral shaft fractures have been described according to the following features [2] :

  • Location - Proximal, middle, or distal
  • Type of fracture line - Transverse, oblique, spiral, comminuted, or segmental
  • Open or closed status

This article focuses on midshaft humerus fractures.

No classification scheme for humeral shaft fractures has gained universal acceptance, though the system developed by the Orthopaedic Trauma Association (OTA) and the Arbeitsgemeinschaft für Osteosynthesefragen (AO) is often employed (see Classification).

Although most fractures of the humeral shaft are inherently unstable, nonoperative treatment remains the standard. [3]  For operative candidates, the role of surgery, as well as which type of surgery is appropriate, is dependent on the patient and the fracture characteristics. [4, 5]

For patient education resources, see the First Aid and Emergencies Center, as well as Broken Arm.



The humeral shaft is defined as the portion of the humerus distal to the surgical neck and proximal to the epicondyles. [6]  The proximal half is almost cylindrical, whereas distally, the anteroposterior diameter narrows into a prismatic shape. The posterior surface (between the medial and lateral borders) is the largest. The radial sulcus, which contains the radial nerve and, at its midpoint, the nutrient foramen, crosses the posterior middle third of the humerus.

The large muscles that surround the humerus prevent direct palpation. The arm is divided into anterior and posterior compartments by two intermuscular septa: medial and lateral. [7] The anterior compartment contains the following:

  • Biceps brachii, coracobrachialis, and brachialis
  • Brachial artery and vein
  • Median, musculocutaneous, and ulnar nerves

The posterior compartment contains the following:

  • Triceps
  • Radial nerve


Each method of humeral shaft fracture treatment is associated with a union rate of higher than 90%. Each fracture must be considered separately and treated accordingly. [8]

Connolly et al assessed the outcome of immediate open reduction and internal fixation (ORIF) in 46 patients with open humeral diaphyseal fractures. [9]  All fractures united primarily in satisfactory angulation of less than 5º in coronal and sagittal planes. In 40 patients, mean time to union was 18.4 weeks; in six, union was delayed (mean time to union, 42.5 weeks). No patient required subsequent surgery to obtain union. Complications were rare (including amputation in three patients and dysesthesia in one), with no deep infections, nonunions, or iatrogenic nerve injuries. Two implants were removed because of discomfort.

Heineman et al conducted a meta-analysis of four trials comparing treatment of humeral shaft fractures with different implants (plates and nails). [10]  After calculating the data from the four trials (203 patients), they found no statistically significant differences between plates and nails with respect to complications, nonunion, infection, nerve palsy, or reoperation.

In a retrospective study, Pretell et al reported that 17 of 19 patients with fractures of the humeral shaft treated with anterograde locked intramedullary nailing were satisfied with the results. [11]  The mean duration of hospitalization after surgery was 4.3 days; there were no complications related to the implants; there were no operative complications; and the average operation time was 48 minutes. The consolidation rate was 80%.

In a systematic review and meta-analysis of the clinical outcomes and pooled complication rate for the use of Surgical Implant Generation Network (SIGN) intramedullary nails in femoral (60%), tibial (38%), and humeral (2%) fracture fixation, all studies that measured clinical outcome indicated that more than 90% of patients achieved full weightbearing status, favorable range of motion (ROM; >90º), or radiographic or clinical union. [12] The overall complication rate was 5.2%; malalignment (>5º angulation in any plane) was the most common complication (7.6%), followed by delayed union or nonunion (6.9%), infection (5.9%), and hardware failure (3.2%).

A 6-year observational cohort study of 95 patients with humeral fractures (20 proximal, 75 diaphyseal) treated with antegrade intramedullary nailing documented improvements in functional recovery for all patients over time but noted better outcomes in patients younger than 65 years. [13] Fracture type and patient gender had no effect on these results at 1 month and 6 months. No infections occurred. Eighteen patients required blood transfusions, and 10 required revision surgery.