Midshaft humeral fractures in children

INTRODUCTION — Fractures of the humeral shaft are uncommon, representing less than 10 percent of all fractures in children [1]. One of the most important features of humeral fractures in children is their ability to remodel and heal with minimal to no deformity despite displacement and angulation. The majority of these fractures can be treated by immobilization alone.

This review addresses midshaft fractures of the humerus in children. Fractures of the proximal and distal humerus, including supracondylar fractures, are presented separately. (See "Supracondylar humeral fractures in children" and "Epicondylar and transphyseal elbow fractures in children" and "Evaluation and management of condylar elbow fractures in children" and "Proximal humeral fractures in children".)

PERTINENT ANATOMY — A thick periosteal sleeve is present along the humeral shaft that limits fracture displacement and promotes healing after fracture. (See "General principles of fracture management: Fracture patterns and description in children", section on 'Fracture patterns'.)

Following a displaced midshaft humeral fracture, the radial nerve is at potential risk for injury. Although nerve injuries may rarely be associated with long-term sequelae, the majority are neurapraxias, such as temporary loss of nerve function (especially motor function) without anatomical nerve disruption.

MECHANISM OF INJURY

Neonates — The humerus is second only to the clavicle as the most commonly fractured bone associated with birth trauma. Neonatal humeral fractures result from rotation or hyperextension of the upper extremity during passage through the birth canal [2]. A complete, transverse midshaft fracture at the medial third of the humerus is the typical fracture type and site (figure 1) [3].

Children and adolescents — Fractures of the midshaft humerus may occur after a fall on an outstretched hand (FOOSH) or from a direct blow to the upper arm [2,4]. Humeral shaft fractures also occur in relatively high energy trauma, such as in a motor vehicle collisions [2,5].

Pathologic fracture — A midshaft humeral fracture which occurs with a history of minimal trauma may suggest a pathologic fracture. The humerus is a common location of bone cysts and other benign lesions [2-6].

Child abuse — A mechanism inconsistent with the injury or a midshaft humeral fracture in a child who is otherwise healthy or younger than two years of age with normal bone density by radiograph should raise concern for child abuse. Two types of humeral shaft injury may result from abusive injury (see "Orthopedic aspects of child abuse", section on 'Humeral fractures'):

●Transverse fracture caused by a direct strike

●Oblique fracture caused by traction with humeral rotation or twisting

Other injuries concerning for child abuse are frequently present (table 1 and table 2) [7].

PHYSICAL FINDINGS

Midshaft humeral fractures — The child with a midshaft humeral fracture usually has mid-arm pain and swelling. Most fractures do not have a visible deformity and are minimally displaced radiographically [2].

Vascular injury is rare. However, midshaft humeral fractures are associated with radial nerve injury, either as a result of the primary injury or as a complication of orthopedic manipulation [2,3]. Injury to the radial nerve will cause numbness to the dorsum of the hand between the first and second metacarpal and motor deficit characterized by diminished thumb and wrist extension and forearm supination [4].

Neonatal fracture — In addition to arm swelling or deformity, the neonate with a midshaft humeral fracture may present with irritability when held and refusal to move the upper extremity ("pseudoparalysis") [6].

Associated findings — After major trauma, midshaft humeral fractures may be associated with life-threatening injuries of the neck, head, and thorax. If present, these injuries should take priority during stabilization of the patient. (See "Trauma management: Approach to the unstable child".)

DIAGNOSIS AND IMAGING — Routine radiographs of the humerus (anterior-posterior and lateral radiographic views) are generally sufficient to diagnose a midshaft humeral fracture. As in every fracture in orthopedics, the joint above and the joint below the fracture should also be seen on radiographs. Dedicated shoulder and elbow series should be obtained if these joints are not adequately visualized on the humeral radiographs [2]. A prominent vascular groove in the distal humerus is a normal finding that should not be confused with a fracture [8].

Midshaft fractures are classified in a descriptive manner by their anatomic location, fracture pattern, displacement, and angulation (figure 2) [2,3]. (See "General principles of fracture management: Fracture patterns and description in children", section on 'Fracture description in children'.)

INITIAL TREATMENT — For children with midshaft humeral fractures, initial therapy consists of pain management, immobilization, and radiographic evaluation [9].

Analgesia — All children with fractures should be assessed for pain and receive appropriate analgesia. (See "Pain in children: Approach to pain assessment and overview of management principles", section on 'Severity assessment'.)

Intranasal fentanyl or intravenous fentanyl or morphine is most appropriate for initial pain control in patients with severe pain and should be given prior to radiographic evaluation. Oral analgesia (eg, ibuprofen) may suffice for patients who have mild or moderate pain.

Immobilization — Immobilization enhances patient comfort and prevents further fracture displacement. The arm may be placed in a sling and swathe or shoulder immobilizer for comfort. Neurovascular status should be checked before and after the patient is placed in a sling.

Orthopedic consultation — Immediate orthopedic consultation should be obtained in any of the following circumstances:

●Open fracture

●Fracture with neurovascular compromise (radial nerve injury)

●Completely displaced fracture

●Midshaft fracture with clinical deformity or angulation more than 20 degrees in children and 10 degrees in adolescents

●Fracture with evidence of compartment syndrome (rare in midshaft humeral fractures)

Child protection — Diagnosis of a humeral fracture in a child with no plausible mechanism of injury in children with normal bone density on radiograph, especially children younger than two years of age, should prompt involvement of an experienced child protection team (eg, social worker, nurse, physician with more extensive experience in the management of child abuse) whenever available. In many parts of the world (including the United States, United Kingdom, and Australia), a mandatory report to appropriate governmental authorities is also required. (See 'Child abuse' above and "Child abuse: Social and medicolegal issues", section on 'Reporting suspected abuse'.)

In addition, the medical care team should ensure that a complete evaluation for child abuse is performed as described separately and work with local Child Protective Services to ensure the safety of other children in the home. (See "Physical child abuse: Diagnostic evaluation and management".)

DEFINITIVE CARE

Infants — For infants, a sling and swathe (with the arm wrapped to the torso by an elastic bandage) is sufficient immobilization for a midshaft humeral fracture regardless of fracture displacement (figure 3). Because of the rapid, predictable healing in this fracture, immobilization may be limited to four weeks (image 1) [2].

Children and adolescents — The thick periosteal sleeve of the humeral shaft often limits fracture displacement and promotes rapid healing.

Immobilization alone — In children or adolescents with incomplete fractures, a sling and swathe (figure 3), collar and cuff sling (figure 4), or shoulder immobilizer may be used for immobilization. For complete or moderately displaced fractures, application of a sugar tong splint to the upper arm and a sling to support the forearm is recommended (figure 5). A hanging long arm cast is an alternative for older children and adolescents (figure 6) [2,4]. The hanging cast uses gravity to decrease fracture deformity by fatiguing the muscles and often improves patient comfort.

Closed reduction — Midshaft fracture with clinical deformity or angulation more than 20 degrees in children and 10 degrees in adolescents warrants consultation with an orthopedic surgeon for closed reduction. Lack of clinical deformity may be considered more important than radiographic alignment in evaluating post-reduction results [2].

After reduction, the child is placed in a coaptation splint (a padded, U-shaped splint placed around the medial and lateral arm and up over the shoulder) for approximately two weeks (figure 7). If the fracture is minimally displaced when reassessed, the child is subsequently placed in a functional clamshell brace (picture 1A-B) until adequate callus formation is seen (approximately four weeks) [10]. For fractures that have acceptable angulation but have some shortening, the child can be treated in a hanging arm cast until adequate healing is seen (figure 6). Shoulder range of motion exercises are typically started four weeks after the original date of injury [2].

Surgical repair — Operative treatment of pediatric humeral shaft fractures is indicated for open fractures or, less commonly, closed fractures when acceptable displacement or angulation cannot be managed with closed means [2,3,11]. Use of external fixation techniques in cases with severe soft tissue or bone loss has also been described [12].

FOLLOW-UP CARE — Patients who have received immobilization alone or closed reduction followed by immobilization should follow up with an orthopedic surgeon with pediatric expertise within 7 to 10 days.

Children who have received operative care (closed reduction with percutaneous pinning or open reduction with internal fixation or fragment removal) should be admitted for 24 to 48 hour observation of neurovascular status and soft tissue compartments. Once discharged, these patients are followed closely and may require weekly orthopedic evaluation with radiographs to determine the optimal timing for subsequent hardware removal.

Most radial nerve deficits associated with midshaft humeral fractures are neurapraxic injuries that resolve with observation.

COMPLICATIONS — Radial nerve palsy and nonunion are the most common complications of humeral shaft fractures in adults but are rarely seen in children [2].

Complete nerve injury is exceedingly rare in closed humeral fractures in children. A radial nerve palsy associated with a closed humeral shaft fracture occurs about 4 percent of the time and should be treated conservatively [13]. Wrist splints and physical therapy should be employed to maintain a full range of motion and prevent wrist contractures. Impaired nerve function usually recovers spontaneously [14]. If there is no evidence of recovery after three months, further evaluation of nerve function should occur with electromyogram and nerve conduction velocity studies [2]. The prognosis for recovery is excellent, and nearly all cases of radial nerve palsy fully resolve [3,13].

Nonunion of the humeral shaft is unusual in children given the capacity of the bone to remodel [15]. Ultrasound bone stimulation can be used to successfully treat delayed union when it occurs.

OUTCOMES — Complications of midshaft humeral fractures are uncommon in the pediatric population. The prognosis for healing and remodeling is excellent, especially in young patients [3].

ADDITIONAL INFORMATION — Several UpToDate topics provide additional information about fractures, including the physiology of fracture healing, how to describe radiographs of fractures to consultants, acute and definitive fracture care (including how to make a cast), and the complications associated with fractures. These topics can be accessed using the links below:

●(See "General principles of fracture management: Bone healing and fracture description".)

●(See "General principles of fracture management: Fracture patterns and description in children".)

●(See "General principles of acute fracture management".)

●(See "General principles of definitive fracture management".)

●(See "General principles of fracture management: Early and late complications".)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: General management of pediatric fractures" and "Society guideline links: Upper extremity, thoracic, and facial fractures in children" and "Society guideline links: Acute pain management".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Basics topic (see "Patient education: How to care for your child's cast (The Basics)")

●Beyond the Basics topic (see "Patient education: Cast and splint care (Beyond the Basics)")

SUMMARY AND RECOMMENDATIONS

●Mechanism of injury – Midshaft humeral fractures are uncommon childhood injuries that typically occur from a fall on an outstretched hand or a direct blow to the upper arm. (See 'Pertinent anatomy' above and 'Mechanism of injury' above.)

A mechanism inconsistent with the presence of a midshaft humeral fracture in an otherwise healthy child with normal bone density by radiograph should raise concern for child abuse and prompt evaluation for child abuse and involvement of a multidisciplinary child protection team lead by a child abuse specialist, especially in a child younger than two years of age. Abusive injury may also cause transverse/oblique or metaphyseal corner chip fractures (figure 2). (See "Orthopedic aspects of child abuse", section on 'Humeral fractures' and "Physical child abuse: Diagnostic evaluation and management".)

●Physical findings – The child with a midshaft humeral fracture usually has mid-arm pain and swelling. (See 'Physical findings' above.)

Detailed neurovascular assessment is important to identify radial nerve deficit manifested by numbness to the dorsum of the hand between the first and second metacarpal, and motor deficit characterized by diminished thumb and wrist extension and decreased forearm supination. (See 'Physical findings' above.)

●Diagnosis and imaging – Routine radiographs of the humerus (anterior-posterior and lateral radiographic views) are generally sufficient to diagnose a midshaft humeral fracture (image 1 and image 2). Analgesia (eg, intranasal fentanyl or intravenous fentanyl or morphine for severe pain or oral ibuprofen for mild or moderate pain) should be given prior to diagnostic imaging. Midshaft fractures are classified in a descriptive manner by their anatomic location, fracture pattern, displacement, and angulation (figure 2). (See 'Diagnosis and imaging' above.)

●Management – Initial treatment of midshaft humeral fractures consists of analgesia, immobilization with a sling and swath or shoulder immobilizer, and diagnostic imaging. The majority of these fractures are treated with immobilization alone and do not require surgical intervention. Type of immobilization depends on the age (see 'Infants' above and 'Immobilization alone' above):

•Infants – Sling and swathe with the arm wrapped to the torso by an elastic bandage (figure 3)

•Children or adolescents – Sling and swathe, collar and cuff sling (figure 4), or shoulder immobilizer

Midshaft fracture with clinical deformity or angulation more than 20 degrees in children and 10 degrees in adolescents warrant consultation with an orthopedic surgeon for closed reduction. (See 'Closed reduction' above.)

Patients who have received immobilization alone or closed reduction followed by immobilization should follow up with an orthopedic surgeon with pediatric expertise within 7 to 10 days. (See 'Follow-up care' above.)

●In addition to fractures that warrant closed reduction, the emergency clinician should obtain prompt orthopedic consultation in patients with the following injuries (see 'Orthopedic consultation' above):

•Open fracture

•Fracture with neurovascular compromise (radial nerve injury)

•Completely displaced fracture

•Fracture with evidence of compartment syndrome (rare in midshaft humeral fractures)