What are stress fractures?
As the name suggests, stress fractures can be small fractures produced by stress, normally with repetitive sub-maximal forces without sufficient rest/recovery. There are a number of other factors that can increase this “stress”. Stress can be both physical and non-physical.
Stress fractures represent a spectrum of injuries ranging from inflammation of the bone periosteum (thin outer layer of the bone) to a complete stress fracture.
Stress fractures can be divided into i) fatigue or ii) insufficiency.
Fatigue = a fracture due to repetitive force leading to an abnormal load on an otherwise normal bone
Insufficiency = a fracture in abnormal bone with normal forces e.g. with osteoporosis
How prevalent are they?
Stress fractures account for 10% of all overuse sports injuries with running being the most commonly associated sport (accounting for 69% of stress fractures).
The most common sites are tibia, navicular, metatarsals and fibula. Less common sites include the femoral neck stress fracture and pelvis. However, stress fractures can occur in any bone that experiences abnormal stress overload with training.
What are the common causes?
- Intensive training load
- Improper footwear
- Poor sleep/recovery
- Steroid use
- Muscle fatigue
- Low vitamin D intake
- Training environment
Who is at risk?
- Women > men
- Hormonal status
- Low bodyweight (<19 BMI)
- Low energy availability and/or eating disorder
- Low bone density conditions such as Osteoporosis (these last 3 all form the condition RED-S – Relative Energy Deficiency in Sport, previously described as the Female Athlete Triad)
- Previous stress fracture
- Recent pregnancy
What are the symptoms?
- Unlike tendinopathy, stress fracture pain continues to increase with activity.
- Difficulty weight bearing after, even with walking.
- Focal point of pain and there may be swelling.
- May not be easily identified in clinic with common Physio/HCP tests
The gold standard to diagnose is through an MRI. Other forms of diagnostic procedures include bone scans and radiography. However, 2/3 of radiographs are normal early in the course of a stress fracture.
What else could be causing the pain?
- Tendinopathy or other soft tissue related issues
- Medial Tibial Stress Syndrome (shin splints)
- Compartment syndrome
How to reduce your risk?
- Change your loading. Some stress fractures will only need a temporary reduction in loading. If high risk stress fractures develop, these may need a period of non-weight bearing to allow the bone to heal
- Some studies suggest increasing your cadence while you’re running can reduce the forces transferred from the ground through the legs and therefore reduce the load through the bones
Sleep! and relative rest
- See an appropriate HCP if you identify with any of the RED-S symptoms
- See a Physio to get advice on your training and symptom management