Fractures

Types of Fracture

A compound fracture is when the skin is broken and the broken bone is exposed to the air. The broken bone can puncture through the skin.

A stable fracture refers to when the sections of bone remain in alignment at the fracture.

A pathological fracture refers to when a bone breaks due to an abnormality within the bone (see below). 

There are terms used to describe in what way a bone breaks:

  • Transverse
  • Oblique
  • Spiral
  • Segmental
  • Comminuted (breaking into multiple fragments)
  • Compression fractures (affecting the vertebrae in the spine)
  • Greenstick
  • Buckle (torus)
  • Salter-Harris (growth plate fracture)

 

Greenstick and buckle fractures typically occur in children rather than adults. Salter-Harris fractures only occur in children (adults do not have growth plates).

 

Wrist Fractures

A Colle’s fracture refers to a transverse fracture of the distal radius near the wrist, causing the distal portion to displace posteriorly (upwards), causing a “dinner fork deformity”. This is usually the result of a fall onto an outstretched hand (FOOSH). 

A scaphoid fracture is often caused by a FOOSH. The scaphoid is one of the carpal bones and is located below the base of the thumb. A key sign of a scaphoid fracture is tenderness in the anatomical snuffbox (the groove between the tendons when extending the thumb). It is worth noting that the scaphoid has a retrograde blood supply, with blood vessels supplying the bone from only one direction. This means a fracture can cut off the blood supply, resulting in avascular necrosis and non-union.

TOM TIP: Some key bones have vulnerable blood supplies, where a fracture can lead to avascular necrosis, impaired healing, and non-union. These are the scaphoid bone, the femoral head, the humeral head and the talus, navicular and fifth metatarsal in the foot.

 

Ankle Fractures

Ankle fractures involve the lateral malleolus (distal fibula) or the medial malleolus (distal tibia).

The Weber classification can be used to describe fractures of the lateral malleolus (distal fibula). The fracture is described in relation to the distal syndesmosis (fibrous join) between the tibia and fibula. This tibiofibular syndesmosis is very important for the stability and function of the ankle joint. If the fracture disrupts the syndesmosis, surgery is more likely to be required in order to regain good stability and function of the joint.

The Weber classification defines fractures of the lateral malleolus as:

  • Type A – below the ankle joint – will leave the syndesmosis intact
  • Type B – at the level of the ankle joint – the syndesmosis will be intact or partially torn 
  • Type C – above the ankle joint – the syndesmosis will be disrupted

 

Pelvic Ring Fractures

The pelvis forms a ring. When one part of the pelvic ring fractures, another part will also fracture (similar to fracturing a polo mint). 

Pelvic fractures often lead to significant intra-abdominal bleeding, either due to vascular injury or from the cancellous bone of the pelvis. This can lead to shock and death, so needs emergency resuscitation and trauma management.

 

Pathological Fractures

Pathological fractures occur due to an underlying disease of the bone, such as a tumour, osteoporosis or Paget’s disease of the bone. They may occur with minor trauma or even spontaneously without any history of trauma. Common sites are the femur and the vertebral bodies. 

The main cancers that metastasise to the bones are (mnemonic: PoRTaBLe):

  • Po – Prostate
  • R Renal 
  • Ta – Thyroid
  • BBreast
  • Le – Lung

 

Fragility Fractures

Fragility fractures occur due to weakness in the bone, usually due to osteoporosis. They often occur without the appropriate trauma that is typically required to break a bone.  For example, a patient may present with a fractured femur after a minor fall.

A patient’s risk of a fragility fracture over the next 10 years can be predicted using the FRAX tool. 

Bone mineral density can be measured using a DEXA scan. 

The WHO criteria for osteopenia and osteoporosis are:

T Score at the Hip

Bone Mineral Density

More than -1

Normal

-1 to -2.5

Osteopenia

Less than -2.5

Osteoporosis

Less than -2.5 plus a fracture

Severe Osteoporosis

 

The NOGG guidelines can be used to guide the medical treatments appropriate for an individual based on their FRAX score. The first-line medical treatments for reducing the risk of fragility fractures are:

  • Calcium and vitamin D
  • Bisphosphonates (e.g., alendronic acid)

 

Bisphosphonates work by interfering with osteoclasts and reducing their activity, preventing the reabsorption of bone. There are a few key side effects to remember:

  • Reflux and oesophageal erosions (oral bisphosphonates are taken on an empty stomach sitting upright for 30 minutes before moving or eating to prevent this)
  • Atypical fractures (e.g. atypical femoral fractures)
  • Osteonecrosis of the jaw
  • Osteonecrosis of the external auditory canal

 

Denosumab is a monoclonal antibody that works by blocking the activity of osteoclasts. It is an alternative to bisphosphonates where they are contraindicated, not tolerated or not effective.

 

Imaging

X-rays are the initial imaging investigation when a bone fracture is suspected. Two views (two x-rays taken from different angles) are always required, as a single view may miss a fraction.

CT scans give a more detailed view of the bones when the x-rays are inconclusive or further information is needed.

 

Principles of Fracture Management

The first principle is to achieve mechanical alignment of the fracture by:

  • Closed reduction via manipulation of the limb
  • Open reduction via surgery

 

The second principle is to provide relative stability for some time to allow healing to occur. This can be done by fixing the bone in the correct position while it heals. There are various ways the bone can be fixed in position:

  • External casts (e.g., plaster cast)
  • K wires
  • Intramedullary wires
  • Intramedullary nails
  • Screws
  • Plate and screws

 

Management

Patients presenting to A&E will be investigated with x-rays to establish the diagnosis. 

Patients with fractures require appropriate pain management. 

Straightforward fractures may be managed in A&E (e.g., a Colle’s fracture in a young adult). They may require closed reduction if the bones are out of alignment. A plaster cast may be applied, and the patient can be discharged with a follow-up appointment in the fracture clinic.

Complex fractures and those requiring surgery (e.g., hip fractures) are referred to the on-call trauma and orthopaedics team. They are admitted and made nil by mouth if they may need an operation. They are discussed at the trauma meeting the following day (typically, this starts at 7.45 am), then seen on the morning ward round. A plan will be made for further management at this stage. 

 

Complications

The complications will depend on the location and nature of the fracture. 

Possible early complications include:

  • Damage to local structures (e.g., tendons, muscles, arteries, nerves, skin and lung)
  • Haemorrhage leading to shock and potentially death
  • Compartment syndrome 
  • Fat embolism (see below)
  • Venous thromboembolism (DVTs and PEs) due to immobility

 

Possible longer-term complications include:

  • Delayed union (slow healing)
  • Malunion (misaligned healing)
  • Non-union (failure to heal)
  • Avascular necrosis (death of the bone)
  • Infection (osteomyelitis)
  • Joint instability
  • Joint stiffness
  • Contractures (tightening of the soft tissues)
  • Arthritis
  • Chronic pain
  • Complex regional pain syndrome

 

Fat Embolism

Fat embolism can occur following the fracture of long bones (e.g., femur). Fat globules are released into the circulation following a fracture (possibly from the bone marrow). These globules may become lodged in blood vessels (e.g., pulmonary arteries) and cause blood flow obstruction. 

Fat embolisation can cause a systemic inflammatory response, resulting in fat embolism syndrome. 

It typically presents around 24-72 hours after the fracture. Gurd’s criteria can be for the diagnosis. 

Gurd’s major criteria:

  • Respiratory distress
  • Petechial rash
  • Cerebral involvement

 

There is a long list of Gurd’s minor criteria, including:

  • Jaundice
  • Thrombocytopenia
  • Fever
  • Tachycardia

 

Operating early to fix the fracture reduces the risk of fat embolism syndrome. 

It can lead to multiple organ failure. Management is supportive while the condition improves. The mortality rate is around 10%. 

 

Last updated August 2021
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