“Bone injury” and “bone stress injury” describes pathologies that affect the structural aspects of bone. These injuries occur on a continuum, from a reaction through to full fracture.

Bone oedema (or edema)

Bone oedema refers to a painful area of reaction within the bone, also known as bone bruising.

This occurs due to direct impact or other bone injury (such as a bone stress reaction).

Symptoms include an ache on loading and residual ache after loading.

There are no interventions that can reduce the recovery time of bone oedema. The approach is typically to minimise the loading on the area to reduce the symptoms while it settles.

Bone stress reaction

Bone stress reactions occur when the rate of bone breakdown (a normal process with loading) exceeds the rate of bone regeneration.

This is most commonly due to excessive loading beyond current bone tolerance or inadequate bone regeneration due to dietary or hormonal causes.

Symptoms usually come on gradually, with pain on loading and a prolonged residual ache afterwards, however there are situations where the pain occurs suddenly.

The most effective intervention is to reduce loading and increase strength training.

If there is a likelihood of hormonal or dietary causes, follow up blood tests are recommended.

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Bone stress fracture

Bone stress fractures are the next step after a stress reaction, with ongoing breakdown leading to a small fracture (crack) in the bone.

Not all bone stress reactions are at risk of progressing to stress fracture. Reactions caused by muscle forces are very unlikely to become stress fractures.

Symptoms include pain worsening with loading, a residual ache lasting days after loading and aching at rest.

The most effective treatment approach includes reduced loading (possibly a moon boot or crutches, depending on the bone affected) and gradual return to loading and strength work.

If there is a likelihood of hormonal or dietary causes, follow up blood tests are recommended.

Example: Tibial stress fracture

Bone fracture

This is a break in the bone due to a single incident of overload.

Initial symptoms include pain on loading and pain at rest, and may include visible deformity.

Management is based around establishing or maintaining good bone alignment and protecting the fracture location while it heals. This includes gradual reloading to stimulate optimal bone healing.

Timeframes for return to loading vary based on patient age and the bone involved, commonly from 4 weeks to 8 weeks although some fracture locations can require longer recovery periods.

Other bone injuries

Occult fracture – a fracture that is difficult to see on basic imaging and may require more complex imaging.

Pathological or insufficiency fracture – a fracture that occurs with a weakened bone structure due to another disease process.

Green stick fracture – an incomplete fracture often seen in children (imagine breaking a green tree branch where only one side of the structure cracks).

Avascular necrosis – bone destruction due to inadequate blood supply to one side of the fracture site.