Fractured Humerus

The humeral head articulates with the glenoid fossa of the scapula. The anatomical neck separates the greater and lesser tuberosities from the humeral head. The long head of biceps runs between the tuberosities in the bicipital groove, and the surgical neck is just below the greater and lesser tuberosities. The radial nerve runs posteriorly around the middle third of the humeral shaft in the spiral groove. The medial and lateral epicondyles are at the lower end of the humerus, and the joint surface consists of the capitulum (articulates with the head of the radius) and the trochlea (articulates with the ulna).

The humerus is a relatively common site of pathological fracture. 8% of humeral shaft fractures in a swedish study were pathological.¹ Suspect pathological fracture if any of the following features are present:

• Bone pain preceding fracture
• Limb swelling predating fracture, or marked post-fracture swelling
• Cystic abnormality of the humerus on x-ray
• History of malignancy, particularly metastatic
• Paget's disease of bone

Classification of humerus fractures is difficult. One method is to classify them as:

• Proximal humerus fractures
• Humeral shaft fractures
• Distal humerus fractures

Epidemiology

• 4-5% of all fractures²

Mechanism of injury

• Usually after fall onto an outstretched hand from standing height
• Can also occur during seizures or electric shock when fracture may be associated with a posterior shoulder dislocation
• Can also result from a direct blow

Age group affected

• Middle age/elderly most commonly affected.³ Common in women. Many patients are osteoporotic.²
• In younger people, same injury mechanism can cause fracture with co-existing shoulder dislocation. In younger age groups, trauma is likely to be of higher energy and resulting injury more serious. Humeral epiphysis separation can occur in adolescents.

Presentation

• History of trauma
• Pain, loss of shoulder/arm function, swelling and bruising

Assessment

• Determine injury mechanism. Is osteoporosis likely?
• Assess for associated injuries to arm/shoulder/chest wall/lungs
• Perform a neurological examination, particularly examining the axillary nerve by testing for sensation in the regimental badge area over the deltoid muscle and assessing upper limb muscle power. Assess for brachial plexus injury through distal neurological examination.
• Check peripheral pulses
• If there are neurological or vascular deficits, orthopaedic referral is required.

Investigations

• Xrays - include AP, transscapular (or Y) and axillary views
• CT scan may be needed in difficult cases

Classification

• Neer classification: based on the 4 usual cleavage lines that occur due to the anatomy of the proximal head of the humerus (the articular segment or head, the lesser tuberosity, the greater tuberosity and the surgical neck/shaft). Two-part, three-part and four-part fractures can occur. The fractures are then classified by their degree of displacement and angulation.
• Considered to be displaced if more than 10mm movement or angulation >45º.
• Surgical neck fractures are the commonest type of proximal humeral fracture.

Management

• General principles: the fracture should be immobilized as soon as possible and potent analgesia given. Keep patient comfortable and minimise any need for movement. Open fractures, those associated with a shoulder dislocation or combined with fracture in forearm are a surgical emergency and an immediate orthopaedic opinion is necessary.
• Most fractures are extra-articular and minimally displaced.
• Up to 85% of proximal humerus fractures can be treated non-operatively.⁴ This involves the use of a sling or shoulder immobiliser. A physiotherapy referral should be made.
• If displaced, surgery may be needed but which surgical technique is used is controversial. Some advocate the use of conservative treatment for some displaced fractures.²
• Surgery involves either closed reduction with percutaneous fixation, open reduction and internal fixation, or proximal humeral head replacement.⁵
• Fracture dislocations and fractures of the anatomical neck should be referred for orthopaedic review.³

Complications

• Neurovascular injury: 21-36% of proximal humerus fractures produce neurovascular injury.⁵ Axillary nerve damage is most common. Suprascapular, radial and musculocutaneous nerves can also be affected. Axillary artery injury may rarely occur (look for expanding mass over proximal shoulder girdle). Brachial artery is also rarely injured.
• Avascular necrosis of the humeral head: more common in complex fractures with multiple fragments where interruption to the blood supply is more likely and in fractures of the surgical neck. Causes pain and stiffness in the shoulder. Shoulder arthroplasty may eventually be needed or may be the initial treatment of choice in the fracture management. However, the development of intramedullary nails and minimally invasive locking plates provides greater ability to fix more complex fractures with less risk to the blood supply.²
• Malunion
• Associated glenohumeral dislocation
• Associated rotator cuff injury

Prognosis

• This depends on fracture type, mechanism of injury and patient's age and underlying health. In general an elderly person with a proximal humerus fracture never regains full range of movement, whether treated conservatively or surgically. The aim is rehabilitation to a functional range of movement.
• Generally recovery takes at least 1 year but union is expected at 6-8 weeks.

Prevention

• Adequate treatment of those at risk of osteoporosis

Epidemiology

• 3% of all fractures
• 3% of fractures in children <16⁷

Mechanism of injury

• A swedish study in 2006 found most are caused by a simple fall¹
• May be linked to non-accidental injury in children <3 years⁷
• Usually direct trauma or torsion injury to upper limb. Occasionally fall onto outstretched abducted arm. Blunt injury/bending forces usually cause transverse fractures. Torsional force tends to result in spiral fracture.

Age group affected

• The swedish study found that most fractures occurred in elderly patients.¹

Presentation

• History of trauma
• Arm pain, swelling and deformity

Assessment

• Neurovascular examination should be performed. Particular attention should be paid to radial nerve assessment.

Investigations

• AP and lateral Xrays of the humerus
• Include views of the shoulder and the elbow

Classification

There is no recognised universally accepted classification. Can be described using:

• Location - proximal, middle, distal. Distal third humeral fractures are also known as Holstein-Lewis fractures.
• Type of fracture line - transverse, oblique, spiral, comminuted, segmental
• Open or closed

Management

• The same general principles as listed above should be applied.
• Most can be treated non-operatively in a hanging arm cast or coaptation splint (a splint from the axilla to the nape of the neck with a stirrup around the elbow) followed by a functional arm brace (this has an anterior and posterior plastic shell held together by adjustable Velcro straps) after 1-3 weeks.⁸ A physiotherapy referral should be made.
• Mildly displaced/overlapping humeral shaft fractures may be treated by closed reduction and long arm splint from shoulder to wrist. After any humeral closed reduction, neurovascular assessment and x-rays should be repeated.
• Surgical fixation may be needed if the fracture is segmental or if there is vascular compromise. This involves open reduction and the use of plates and screws or intramedullary fixation/nailing. Radial nerve injury, which may only be temporary, is a risk in any operative procedure.

Complications

• Radial nerve injury: occurs in 11.8% of fractures.⁹ Most common in distal third fractures.¹⁰ More common in transverse or spiral fracture.⁹ Spontaneous recovery occurs in 70.7% treated conservatively.⁹ Initial expectant treatment may avoid unnecessary operations.⁹
• Brachial artery injury
• Non-union

Prognosis

• Usually heal within 4 months⁸