Distal humerus fracture
Anatomy of the healthy elbow.The distal humerus is located close to the elbow joint

Definition

Also named supracondylar fracture, a distal humerus fracture is a type of elbow fracture involving the lower (distal) part of the arm bone. At the elbow the humerus connects with the ulna and allows the rotation of the ulna when the hand is moved palm up or palm down. A distal humerus fracture can impair or block completely the movements of the elbow.

Distal humerus fracture

Pathology

The fracture of the distal humerus comprises 2% of all adult fractures but is very common in children (up to 60%). It is found either as an isolated fracture or in conjunction with other fractures of the arm and elbow joint. It is generally defined as an extension or flexion fracture.

Injuries associated with a distal humerus fracture are:

Elbow dislocation

Vascular damage (brachial artery tear or compression)

Compartment syndrome of the arm and necrosis of soft tissue due poor blood supply

Injuries to the radial nerve, causing temporary/permanent flexion of the wrist (drop hand)

AO Müller Classification of distal humerus fractures in children

Classification

In adults, the classification of distal humerus fractures refers to the mechanisms of injury:

Extension-type (98%): the distal fragment is displaced towards the back (posteriorly)

Flexion-type (uncommon): the distal fragment is displaced to the front (anteriorly)

In children, the Gartland classification for extension type of distal humerus fractures corresponds to the Arbeitsgemeinschaft Osteosynthese (AO) Müller classification for adults as mentioned below in the parentheses. 

Type I (extra-articular fracture): undisplaced fractures with unaltered bone alignment

Type II (partial articular fracture): posterior displacement fracture retaining the integrity of the posterior segment of the bone

Type III (complete articular fracture): complete displacement of the distal fragment posteriorly.

Left: Distal radius intraarticular, displaced fracture; Middle: Older distal radius fracture with callus formation; Right: Distal radius and ulna fracture, extraarticular and displaced

No 2.

Intra-articular fracture extends to the wrist joint (or articulation)

Extra-articular fracture is located outside of the wrist joint

Open fracture when bone fragments perforate the skin

Comminuted fracture when the bone breaks into multiple fragments

Non-displaced when the anatomical alignment of the bone is maintained or displaced when the bone fragments move apart.

Melone’s classification describes the characteristics of intra-articular fractures of the radius:

i    Stable fracture

ii    Unstable "die-punch"

iii   "Spike" fracture

iv Split fracture

v   Explosion injuries

Acetabular fracture of the pelvis

Acetabular fractures

These fractures are divided into:

Anterior pillar (not weight bearing part of joint)

Posterior pillar (often associated with dislocation of the hip including the weight bearing part of joint)

Transverse

Comminuted involving both column type 

Sacral / coccygeal fractures

The sacrum is a triangular-shaped bone formed by 5 fused vertebrae, which provide a posterior wall to the pelvic ring. At each side of the sacrum, the ala structures articulate with the ilium bones forming the sacro-iliac joints. Sacral fractures are usually parallel to the spine and can involve the ala. Less frequently sacral fractures may display an “H” shape, including a transversal fracture uniting both sides of the sacrum. Three zones are described where sacral fractures can occur that are along vertical lines relative to the alignment of the foramina. Sacral fractures may result in sacral instability and require treatment via sacroplasty (injection of bone glue into the fracture). Surgery is necessary in case of associated neurological symptoms.

Fractures of the coccyx involve the tailbone, the terminal portion of the spine situated below the sacrum formed by 3 to 5 fused vertebrae. Coccyx fractures occur when falling on a seated position. They are more common in elderly women and seldom require surgical treatment.

Falls and traumatic events can cause distal humerus fractures

Causes

Distal humerus fractures are caused by direct trauma to the arm or elbow and by axial loading transmitted through the elbow. Most common causes are:

Traumatic event (eg. motor vehicle, bicycle accidents)

Fall with the outstretched arm where the ulna pushes towards the humerus

Fall on the flexed elbow

Direct impact with a hard object (hockey/baseball bat, car parts during a collision)

Pathological fractures due to osteoporosis or cancerous metastatic growth

Increased age, osteoporosis and poor balance are risk factors for a distal humerus fracture

Risk factors

The most frequent risk factors leading to a distal humerus fracture include:

Tendency to fall in elderly individuals (poor vision, lack of physical exercise)

Medical conditions (diabetes, seizure)

Sports (bicycle, horse riding)

Contact sports (football, rugby)

Post-menopausal age in women

Cancerous metastases

Patients with distal humerus fracture are unable to move the arm and flex the elbow

Symptoms

The most common symptoms of a distal humerus fracture are:

Severe acute pain at time of accident

Pain at touch

Swelling

Bruising

Obvious deformity of the distal arm

Inability to move the elbow

Bone exiting the skin in open fractures

Medical examination including testing of radial nerve integrity

Diagnosis

The physical examination begins with the medical history including the causes leading to the distal humerus fracture. The examiner will look for the presence of bruises of the distal arm as a sign of possible humerus fracture. Additional evaluation includes:

Changes in the elbow contour

Restrictions in the range of movement of the elbow, fingers and wrist

Test for nerve damage (sensation at touch, muscle weakness, nerve palsy)

Monitoring of radial and ulnar artery pulses to assess vascular integrity

X-rays are the first approach to detect a distal humerus fractures and assess its classification. A CT scan may be performed if necessary to explore further the type of fracture.

Assessment of the radial nerve

The radial nerve innervates the dorsal extrinsic muscles in the forearm. Injury of this nerve may ca0use hand drop. Functional tests of the radial nerve:

Extension of the wrist and metacarpo-phalangeal (MCP) joints with abduction and extension of the thumb

On examination, the fingers are in flexion at the MCP joints and the thumb are adducted

Dysesthesia or anaesthesia on the dorsum of the thumb

Rarely, the median or ulnar nerves are affected in parallel to injuries to the radial nerve.

Treatment

Patient with a cast for conservative treatment of distal humerus fracture

Nonoperative treatment

In case of undisplaced or minimally displaced distal humeral fractures conservative treatment forms a standard management. A splint or sling is applied and frequent X-rays taken to monitor the progress of fracture healing. During the initial period after injury the elbow is immobilised, after which a gentle physiotherapy can begin.

Additional treatments include:

Ice pads

Administration of NSAIDs

Pain killers

‍Surgical treatment of distal humerus fractures with olecranon osteotomy to access the distal humerus and allow bone fixation

Surgical treatment

Surgery is required in displaced fractures and open distal humerus fractures. Metal implants are used to repair bone fragments and gain structural alignment.

An external fixator is used when severe, open fractures produce multiple fragments or in patients who cannot be operated, due to medical conditions or the occurrence of multiple injuries. External fixators are connected to the bone with screws inserted through the skin to reduce the fractured humerus and allow for repair in a correct position. Once the patient’s health has improved the surgical internal fixation can be performed. In some rare cases the external fixator is kept until the fracture has healed completely.

Open surgery begins with an incision on the back of the elbow. An osteotomy (bone removal) of the olecranon is performed to allow a better access to the distal humerus. The olecranon is then repaired at the end of the operation. A number of metal implants are used to fix the fracture: pins, wires, plates, and screws. In severe cases the loss of bone caused by the fracture is replaced with homologous bone graft taken from the iliac crest of the hip, cadaver bone or artificial calcium rich material. If it is not possible to repair the fracture of the distal humerus due to abundant comminution and bone loss, the elbow joint may be replaced with a metal prosthesis.

Complications

With either conservative or surgical treatment, complications after distal humerus fracture can occur:

Non-union of the fracture (when the gap between the bone extremities is not closed)

Mal-union when the fracture heals with abnormal bone alignment

Infection

Post-surgery pain

Temporary damage to the radial nerve

Vascular damage

Joint stiffness of the shoulder and elbow

Ossification of soft tissues or heterotopic ossification in adjacent muscles, tendons

Second surgery in case of non union and removal of metal

Massage and joint mobilisation help restoring elbow function after a distal humerus fracture

Rehabilitation

Initially, after either conservative or surgical treatment a cast or splint is applied in most patients with distal humerus fracture. Physical therapy can commence as soon as the fracture is considered to be stable to prevent elbow stiffness, which may occur after prolonged immobilisation. NSAIDs and pain medications can aid the convalescence by reducing inflammation, swelling and pain. Recovery after distal humerus fracture can be a lengthy process (6 months) and the patient may never be able to lift weights or straighten the arm in full. Patients often display an extension deficit of up to 25 degree without any major functional impairment due to compensation of other joints of the affected arm, i.e. shoulder and wrist joint. Standard rehabilitative therapy also includes:

Massage

Dry needling

Joint mobilisation

Stretches

Electrotherapy

Activity modification advice

Return to sport/work plan

Postural taping

Early diagnosis of osteoporosis in postmenopausal women via bone density assessment followed by treatment reduces the risk of fractures

Prevention

The main preventative measure aims at reducing the risk of falls in the elderly and protect the arm if collisions occur during sport or biking/motor biking in younger individuals.

Other preventive strategies are:

Elbow bracing when returning to sport

Postural taping

Osteoporosis treatment

Use of devices to improve elderly stability and avoid falls

Modification of physical activities

Physical exercise to improve muscle strength, flexibility and posture