Introduction:
The shoulder is made up of three bones, namely, the clavicle (collar bone), the scapula (shoulder blade), and the humerus (upper arm bone). The humerus is a long bone extending from the shoulder joint to the elbow joint. It is the largest bone in the upper extremity, which articulates with the glenohumeral joint proximally and the radius and the ulnar bones at the elbow joint distally. The humerus bone is divided into the proximal portion, the humeral neck, the humeral shaft, and the distal portion. The proximal portion is the head of the humerus bone, which forms a ball and socket joint with the glenoid fossa (cavity) of the scapula bone. The anatomical neck of the humerus bone divides the head of the bone from the greater and lesser tubercles; following the tubercles is the surgical neck which is highly susceptible to fractures. The shaft is a cylindrically shaped portion that contains the deltoid tubercle. The distal portion of the humerus bone is comparatively wider and forms the medial and lateral epicondyles. The humerus bone is supplied by the humeral artery, which is a branch of the axillary artery, and the nerve supply is by the axillary nerve.
What Is a Humerus Fracture?
A break or discontinuity in the upper arm bone is called a humerus fracture. It is a common fracture mostly seen in young individuals due to high-energy trauma, falls during sports or physical activities in children and adolescents, or in elderly people due to low-energy trauma such as falls on an outstretched arm, especially females with osteoporosis (low bone density) or weak and fragile bones. Fractures occurring due to falls may result in the break of proximal or mid-shaft humerus fractures, whereas high-impact trauma may result in the fracture of the distal humerus. It may be a nondisplaced (fracture or a crack, but bones are aligned), a simple fracture, or a displaced fracture (bones are out of alignment), depending on the cause of injury.
What Are the Types of Humerus Fractures?
Humerus fractures can be classified into three types based on their location:
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Proximal Humerus Fractures: A fracture of the upper part of the humerus bone.
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Midshaft Humeral Fractures: A fracture of the middle portion of the humerus bone.
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Distal Humerus Fractures: A fracture of the lower part or fractures occurring near the elbow.
What Are the Causes of Humerus Fractures?
Some of the causes of humerus fractures include:
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Motor vehicle accidents and falls due to sports injuries are mainly seen in young adults.
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Falls during physical activities, especially in children and adolescents.
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It occurs in elderly people with osteoporosis (a condition in which the bones are weak and brittle) due to falls on an outstretched hand.
What Are the Signs and Symptoms of Humerus Fracture?
Some of the signs and symptoms of humerus fractures include:
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Severe pain and swelling at the fracture site.
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Restricted movement of the arm.
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Presence of skin abrasions, bruises, and lacerations in case of motor vehicle collisions.
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A significant deformity may be seen in the case of severe fractures.
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Numbness or loss of sensation in the upper arm in cases of axillary nerve injury.
How Is a Humerus Fracture Diagnosed?
A complete medical history of the patient is taken, including the description of the event, the intensity of pain, previous injuries or surgeries to the same limb, social conditions, and the general health of the patient.
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Inspection of the fracture site is done to assess for any wounds, injuries, lacerations, abrasions, or any signs of open fractures, such as extending to the chest, arm, forearm, etc., in case of high-energy trauma.
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Tenderness on palpation and pain during range of motion assessment is observed. In cases of proximal humerus fractures, loss of deltoid contour may be seen in the case of high-energy collisions, suggesting dislocated shoulders.
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A neurovascular examination may be done in cases of suspicion of nerve involvement.
Radiological investigations such as orthogonal imaging are advised, which include:
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A true anteroposterior (AP) view, a scapular Y view, and axillary lateral views help to determine the type, extent, and severity of the fracture, along with any associated fractures or injuries to the surrounding areas. In cases of suspected humerus shaft fractures, AP and lateral views are advised, along with the joint above and below; in suspected cases of distal humerus fractures, AP and lateral views, including the elbow (should include the entire humerus and the forearm) is advised.
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A computed tomography (CT Scan) is preferred in some cases where joint involvement is suspected, or the position of the humeral head or the greater tuberosity is uncertain. It also helps decide whether fixation or reconstruction is appropriate to manage the fracture during surgical planning.
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Magnetic resonance imaging (MRI) is advised in rare cases where the involvement of rotator cuff muscles (the group of shoulder muscles responsible for movement) is suspected.
How Is a Humerus Fracture Managed?
Humerus fractures can be managed by nonoperative and operative treatments, depending on the type and severity of the fracture, along with the general health of the patient. Initial management comprises medications to control pain, such as non-steroidal anti-inflammatory drugs such as Ibuprofen, Acetaminophen, etc.
Non-surgical treatment is recommended for nondisplaced or minimally displaced surgical neck fractures, and greater tuberosity fractures of less than 5 mm (millimeters), in patients who are not ideal for surgeries. It includes:
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In cases of proximal humerus fractures, immobilization of the fracture is performed with a sling for around two to three weeks, followed by a gentle progressive rehabilitation or early range of motion exercises such as shoulder pendulum exercises after 10 to 14 days following the injury, along with regular monitoring through radiographs to ensure proper healing. Active range of motion exercises starts after six weeks. Most humerus fractures are managed conservatively and with immediate physical therapy, resulting in faster patient recovery.
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In humeral shaft fractures, a Sarmiento brace is recommended for immobilization, facilitating movements above and below the shoulder joint. It minimizes shoulder stiffness and can be removable to maintain better axillary hygiene. Fracture alignment is maintained by the soft tissue envelope of the upper arm called the inner splint. Periodic monitoring is done weekly by radiographs for about three to four weeks, followed by the application of functional braces.
Surgical management is recommended in open or displaced fractures and multiple trauma with soft tissue involvement. It includes:
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Closed Reduction and Percutaneous Pinning: It is indicated in two-part surgical neck fractures, type I detail humerus fractures, proximal humerus fractures of two-part, three-part, and four-part fractures, with minimum comminution and intact medial calcar. The fracture is reduced by closed reduction (traction and reversal of the mechanism of injury without surgery) using Joystick pins. Fixation is done with the threaded pins to achieve stability. It is recommended in patients with good bone quality and minimal comminution.
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Open Reduction and Internal Fixation: It is indicated in type II distal humerus fractures, displaced two-part, three-part, and four-part proximal humerus fractures, and fractures of greater tuberosity with more than 5 mm displacement. The deltopectoral approach is commonly preferred through direct lateral or anterolateral incisions, and access is gained to align the bones in cases of proximal and anterolateral approach for humeral shaft fractures. Internal fixation is done through implants like locking plates, transosseous suture fixation, or tension band wiring of fractured fragments, to achieve stabilization and promote healing.
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Intramedullary Nailing: It is indicated in surgical neck fractures, three-part greater tuberosity fractures, or combined proximal and humeral shaft fractures. This procedure is done following closed or open reduction wherein titanium nails are inserted across the fractured fragments and fixed at both ends with the help of screws, which stabilizes the bone and facilitates healing. Intramedullary rodding is recommended in the case of surgical neck fractures, three-part greater tuberosity fractures in young individuals, or in cases of combined proximal humerus and shaft fractures.
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Shoulder Reconstruction or Arthroplasty: It is a procedure during which a partial or complete humeral segment is removed and replaced by an implant or artificial humeral component. It is recommended in non-reconstructible four-part fractures, severely dislocated fractures, and head-splitting fractures, failed reconstruction surgeries. Hemiarthroplasty is advised in elderly people who are not amenable to ORIF, and total shoulder arthroplasty is indicated in cases of glenoid surface or rotator cuff muscle injury. It may be associated with complications like infections at the surgical site, loosening of the implant component, and glenoid bone loss.
What Are the Complications of Humerus Fracture?
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Pressure build-up in the muscles can occur due to trauma, resulting in reduced blood supply and oxygen to the tissues and severe pain called acute compartment syndrome.
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Axillary nerve injury and radial nerve palsy is the most feared complication of humerus fractures, mainly due to the trauma, ORIF, or intramedullary nailing.
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An open fracture may result in bone infection, leading to delayed wound healing.
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Nonunion of the fractured fragments or malunion (abnormal union) following treatment, especially in cases of closed reduction or due to bone infections.
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Excessive soft tissue stripping and fracture risk at the ends of the metal plate implants.
Conclusion:
A humerus fracture is a break or discontinuity in the upper arm bone characterized by severe pain, swelling, restricted movement, and significant deformity. It is commonly seen in young adults due to motor accidents or falls on an outstretched hand, mainly seen in children and elderly people with osteoporosis. It is usually managed by conservative management with cast or brace immobilization and physical therapy or by surgical intervention and rehabilitation.
