Bone Stress Injury

Bone Stress Injury: Low vs High Risk Sites

Ever had a persistent ache that starts during exercise, disappears with rest, then slowly gets worse each week? It’s a common story, and it could be a bone stress injury.

Bone stress injuries (BSI) are most commonly seen in female adolescents and young adults, particularly active individuals in their late teens to early 30s who are involved in running and high-impact sports.

Understanding the difference between low and high risk bone stress injury sites / location is essential. It helps determine how long recovery might take and the best way to manage it in order to return to sport safely.

What is a Bone Stress Injury?

A bone stress injury occurs when repeated loading overwhelms the bone’s ability to repair itself. Similar to training muscles, bones change and adapt to loads by repairing microdamage which increases bone density and makes them stronger. This is why strength training is very important across all ages. However, when the balance between damage and repair is disrupted, microdamage begins to accumulate and can cause a bone stress injury (Burr, 2002; Warden et al., 2006).

Over time, this can progress through a continuum:

· Stress reaction (early stage)

· Stress fracture (more advanced)

· Complete fracture (severe)

Pain is usually the first sign, often starting subtly and worsening with continued activity. This is why it is important to listen to your pain and seek advice from a health care professional as early as you can.

Why Do Low vs High Risk Sites/Location Matter?

Not all bone stress injuries behave the same way. Some heal quickly with simple treatment, while others have a higher risk of complications and require different management.

The distinction between low and high risk sites is based on:

· The type of forces applied (compression vs tension)

· The blood supply to the area

· The bones’ ability to heal

This classification helps guide treatment decisions and recovery timelines.

Low Risk BSI Sites

Low risk sites are generally more forgiving and respond well to conservative treatment.

Common Low Risk Sites

· Posteromedial tibia (inner shin)

· Fibula (outer shin)

· Calcaneus (heel)

· Pelvis

· Second–fourth metatarsals (mid-foot bones)

Why They Heal Well

These areas are exposed mainly to compressive forces, which are better tolerated by bone. They also tend to have a good blood supply, supporting healing (Boden et al., 2001).

Typical Recovery

· Managed with reduced loading and rehab

· Gradual return to activity

· Often recover within 8–13 weeks depending on severity (Nattiv et al., 2013)

Bone Stress Injury: High Risk Sites Explained

High risk sites require more caution due to their increased likelihood of complications.

Common High Risk Sites:

· Anterior tibia (front of shin)

· Navicular (one of the mid-foot bones)

· Femoral neck (upper thigh bone)

· Fifth metatarsal base (outer foot bone)

· Patella (knee cap)

· Medial malleolus (inside ankle bone)

Why They Are Higher Risk

These areas often experience tensile (pulling) forces which can lead to more severe outcomes. Combined with poorer blood supply, this increases the risk of:

· Delayed healing

· Non-union (failure of healing)

· Progression to a complete fracture (commonly referred to as a “break”)

Typical Recovery

· Requires strict load management, such as non-weight bearing

· May involve crutches, casting, or a boot

· Less commonly may require surgery

· Recovery often exceeds 20 weeks (Dobrindt et al., 2012)

Summary of Differences between Low vs High Risk Sites:

Feature Low Risk Sites High Risk Sites

Bone forces Compression Tension

Blood supply Good Reduced

Healing reliability High Lower

Recovery time Shorter Longer

What Causes Bone Stress Injuries?

BSIs don’t happen from just one factor, they usually develop from a combination of stress on the bone and reduced ability to tolerate that stress (Warden et al., 2014).

Training Factors

· Rapid increases in training load

· Sudden changes in surface or footwear

· Inadequate recovery

Even small increases, if too fast, can disrupt bone adaptation and lead to injury (Bennell et al., 1996; Buist et al., 2008). For example, if you are transitioning between “off-season” to “on-season” for your sport without a gradual “return to training program” whereby your training load suddenly increases from very little to a lot in a short period of time. This can significantly increase your risk of injury.

Biomechanics

· Poor running technique

· Increased loading rates

· Movement patterns that overload certain areas

These factors can increase stress on specific bones (Milner et al., 2006; Pohl et al., 2008).

Muscle Fatigue

Muscles help absorb impact. When fatigued, more load is transferred to bone, increasing injury risk (Milgrom et al., 2007).

Nutrition & Bone Health

· Low energy availability

· Calcium or vitamin D deficiency

· Hormonal factors

These reduce the bone’s ability to repair itself and adapt (Nattiv et al., 2007; Nieves et al., 2010).

Why Early Diagnosis is Critical

A key message from research is simple: the earlier a bone stress injury is diagnosed, the better the outcome.

Early-stage injuries respond quickly to treatment. Delayed diagnosis allows the injury to progress, leading to longer recovery times and higher complication risk (Warden et al., 2014).

MRI is usually the best imaging tool for diagnosis, as it can detect early bone changes before fractures occur (Gaeta et al., 2005).

How We Manage Bone Stress Injury

At our clinic, we take an evidence-based, holistic approach to bone stress injury management:

· Physiotherapy: assessment, referral for imaging, diagnosis, injury management

· Exercise Physiology: guided return-to-running programs

· Myotherapy: soft tissue support

· Dietetics: optimising nutrition for healing

Treating both the symptoms and the underlying causes is key to preventing recurrence (Warden et al., 2006).

When Should You Seek Help?

Book a physiotherapy appointment if you notice:

· Localised bone pain during activity

· Pain that returns each training session

· Symptoms that persist despite rest

· Recurrent injuries

Ignoring early signs can turn a small issue into a long-term setback.

Final Thoughts

A bone stress injury is not something to push through. Understanding whether your injury is at a low or high risk site can significantly impact your recovery and long-term outcomes.

With the right diagnosis, a structured rehab plan, and support from a multidisciplinary team, you can recover well and reduce your risk of re-injury.

 

Phoebe Walker

Physiotherapist