Humeral Shaft Fractures

Key Points:

  • There is a bimodal distribution with fractures commonly occurring in children younger than 3 or older than 12
  • Radial nerve palsies are commonly encountered and treatment depends on whether the palsy is primary or secondary
  • The majority of injuries can be treated nonoperatively
  • Indications for operative treatment include open injuries, fractures with vascular compromise, floating elbow injuries, and unacceptable alignment

Description:

There is not a standard classification system for humeral shaft fractures. The anatomic location of the fracture, fracture pattern (transverse, oblique, spiral), and amount and direction of angulation and displacement are criteria used to describe fractures.

Epidemiology:

Humeral shaft fractures account for approximately 20% of fractures of the humerus in children. The incidence is thought to be between 12 and 30 per 100,000 per year. There is a bimodal distribution of fractures with the majority occurring in children younger than 3 or older than 12. 

Clinical Findings:

Symptoms will vary based upon the age of the patient as well as the mechanism of injury. In birth-related trauma, the presenting complaint may be failure of the child to use the affected arm. Examination may reveal tenderness about the fracture site or frank motion and crepitus at the fracture site.

Older children will often present with pain, swelling, and ecchymosis. The patient will typically splint the arm against the body to minimize motion. Examination may reveal an obvious deformity of the arm and palpation may elicit tenderness or crepitus over the area of the fracture.

Imaging Studies:

An AP and lateral view of the humerus should be obtained when a humeral shaft fracture is suspected. If physical examination suggests injury to the shoulder, elbow, forearm, or wrist; appropriate radiographs should also be obtained. Further imaging such as CT or MRI may be indicated if a pathologic fracture is 
suspected. 

Etiology:

Multiple mechanisms can produce humeral shaft fractures. Birth-related fractures are not uncommon and factors such as macrosomia, breech delivery, or difficult delivery may be risk factors. Non-accidental trauma (NAT) is also a consideration. Though previously felt to be highly associated with NAT, a recent 
study reported that only 18% of humeral shaft fractures in children younger than 3 were a result of NAT. In older children and adolescents, fractures may result from direct trauma to the arm, falls, MVCs, or sports injuries. The humerus is a common site for benign lesions such as unicameral bone cysts. A pathologic fracture through the cyst may occur as a result of seemingly innocuous trauma.

Treatment:

The majority of fractures are treated nonoperatively. There is tremendous remodeling potential in children and thus 20° of coronal plan angulation (varus/valgus), 20° of sagittal plan angulation (procurvatum), 15° of rotation, and up to 1-2 cm of shortening may be acceptable. There are multiple techniques for immobilization including sling, sling-and-swath, coaptation splint (essentially a 
sugar-tong splint for the upper extremity, which should extend past the shoulder joint on the lateral side in more proximal fractures), functional bracing, and hanging arm casts. Functional bracing, initially described by Sarmiento, offers multiple advantages. Braces are lightweight, fairly easy to apply, and allow elbow motion. Patients, however, may not tolerate a functional brace immediately after the injury so a hanging arm cast or coaptation splint is frequently used for 7-10 days. In adolescents, immobilization is typically continued for 6-8 weeks. However, once adequate callus develops (3-4 weeks after injury) the child may be able to perform protected range of motion out of immobilization. Return to athletics may be delayed for up to 3 months depending on the age of the child and the degree of healing.     

Indications for operative treatment include open fractures, fractures with associated vascular injuries, “floating elbow” injuries (humerus fracture with associated fracture of the forearm), and failure to achieve adequate reduction with nonoperative measures. Similar to adults, multi-extremity trauma is a relative indication for surgical fixation to allow early mobilization. Surgical options include open reduction internal fixation (ORIF) with plate and screws, external fixation, and flexible intramedullary nailing.

ORIF is typically performed with 3.5 or 4.5mm plates depending on the size of the patient. An anterolateral, direct lateral, or posterolateral approach can be utilized based upon the fracture pattern and surgeon preference. Ensuring that the radial nerve is not entrapped under the plate is imperative. Six cortices of fixation are necessary above and below the fracture site. Intramedullary nailing is 
another surgical option for transverse or short oblique fractures. This technique relies on indirect reduction and a “length-stable” fracture pattern but offers the advantage of a smaller surgical incision and less surgical dissection. External fixation is an option for open fractures with extensive soft tissue loss or in critically ill multi-trauma patients. 

Complications:

Nerve palsy

Radial nerve palsy is seen in up to 5% of humeral shaft fractures and may either be primary (seen at initial presentation) or secondary (following manipulation when the nerve was initially intact). The management of these injuries is somewhat more controversial. Generally, observation is recommended if adequate reduction can be obtained in fractures with associated primary radial nerve palsy with recovery expected in 78-100% of patients. Exploration with repair, reconstruction, or neurolysis is indicated if there is no recovery after 3-6 months of observation. Exploration with ORIF is a relative indication in patients with secondary nerve palsies, though this is controversial. 

Vascular injury

Vascular injury is seen infrequently with humeral shaft fractures but requires immediate evaluation and treatment. A fracture requiring vascular repair is an indication for either ORIF or external fixation. 

Malunion / Nonunion

Due to the tremendous remodeling potential and compensatory range of motion at the shoulder and elbow, functionally-limiting malunion is fortunately uncommon.  Nonunion is also uncommon.

References:

  1. Bae DS. Humeral Shaft and Proximal Humerus, Shoulder Dislocation. In: Flynn JM, Skaggs DL, Waters PM, eds. Fractures in Children. 8th ed. Philadelphia: Wolters Kluwer; 2015:784-99.
  2. Bullock DP, Koval KJ, Moen KY, Carney BT, Spratt KF. Hospitalized cases of child abuse in America: who, what, when, and where. J Pediatr Orthop. 2009 Apr-May;29(3):231-7.
  3. Herring JA, Ho C. Upper Extremity Injuries. In: Herring JA, ed. Tachdjian’s Pediatric Orthopaedics. 5th ed. Philadelphia: Elsevier Saunders; 2014:1262-4.

Top Contributors:

Jeremy Rush MD