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The Bone Stress Continuum

Bone stress injuries represent a progression of injuries that occur when the bones become overloaded from repetitive micro-trauma. These injuries exist on a continuum – beginning with a bone strain, then progressing to a stress reaction, and later a stress fracture if not managed well. Bone stress is common in the athletic and activity community, accounting for 10% of all sports-related injuries(1) and up to 30% of running injuries(2).

Stress fracture of metatarsal bone

Common locations of Bone Stress Injuries(2):

  • The front or inside of the tibia (i.e. the shin bone)
  • The fibula (i.e. on the outside of the calf)
  • The metatarsal or carpal bones of the foot
  • The medial malleolus of the ankle
  • The neck or shaft of the femur (i.e. the thigh bone)
  • The calcaneus (i.e. the heel bone)
How do Bone Stress Injuries occur?

In normal healthy bone, new activities or increased amounts loading stimulate turn-over of bone cells. First, the body breaks down select portions of the bone, temporarily weakening it, then within 1-2weeks new bone tissue is laid down. Once established, the new bone is stronger, denser and better adapted to the new activity or increase load.

However, if we continue high loading or impact activities during this turn-over period we don’t give our bones adequate time to recover. Overtime, the overloaded bone will accumulate micro-fractures and eventually break down, developing into what we call a bone stress injury.

Right foot xray showing stress fracture
Stages of Bone Stress Injuries

There are 3 progressive stages of bone stress injuries:

  1. Bone strain: there are signs of bone stress on medical imaging but a person is not yet experiencing symptoms.
  2. Stress reaction: bone stress injury severe enough to cause focal pain on the bone, which worsens with sporting activity. People will often also experience tenderness to the touch.
  3. Stress fracture: final stage of the bone stress continuum when a fracture or break in the bone develops, which can be seen on medical imaging. Typically pain is very pronounced in a clear localised area, and often bearing weight on the limb is enough to provoke pain.
Tibial stress fracture
How do we treat Bone Stress Injuries?

Management of bone stress depends on a number of variables, including which bone is affected, location of injury and stage of injury.

First and foremost, healing from a bone stress injury requires adequate time for new bone tissue to be laid down and the region of bone stress to heal. To facilitate this, a person may need a time of complete rest from sporting activities or a period non-weight bearing with a cast or brace. This is highly dependent on the severity of the injury.

Following this a gradual return to activity is needed, while respecting the bone’s normally turn-over cycle. This is best guided by clinical tests, performed by a Physio or Sport’s chiro. Usually, pain-free walking and no tenderness along the injury site are good signs that a person is ready to move to the next level of load.

Non weight bearing using a cast or brace

References
1. Spitz DJ, Newberg AH. Imaging of stress fractures in the athlete. Radiol Clin North Am. 2002 Mar;40(2):313-31. Review. PubMed PMID: 12118827.
2. Robertson GA, Wood AM. Lower limb stress fractures in sport: Optimising their management and outcome. World J Orthop. 2017 Mar 18;8(3):242-255. doi: 10.5312/wjo.v8.i3.242. eCollection 2017 Mar 18. Review. PubMed PMID: 28361017; PubMed Central PMCID: PMC5359760.

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