More Than “Shin Splints”: Assessing Bone Stress Injuries in Runners

Bone Stress Injuries (BSIs) rely heavily on accurate and early diagnosis, as improper management can result in significant complications like further injury and delayed, or even failed, return to running or sport.

Tibial BSIs are unfortunately common among runners. We may be prone to brushing off runners with shin pain as having “shin splints”, but this could be a mistake. Early detection and intervention for tibial BSIs is crucial in preventing further damage and ensuring proper healing. So, we must be ready to spot these injuries and be able to differentiate them from other conditions, like “shin splints”. Beau Walker Tyrell’s Case Study on a runner with tibial BSIs is one of the best resources you can ask for when it comes to understanding BSIs! It was used to help write this blog, and videos from Beau’s Case Study will be included to help illustrate some key points.

If you’d like to see exactly how expert physio Beau Walker Tyrell assessed a real patient with tibial bone stress, check out his full Case Study HERE. With Case Studies you can step inside the minds of experts and apply their strategies to get better results with your patients. Learn more here.

What exactly is a BSI, and is it different from a stress fracture?

Both of these exist along a continuum, and a stress fracture occurs towards the end of said continuum. Our bones are constantly remodeling – they are being broken down and built back up via our osteoclasts and osteoblasts, respectively.

BSIs occur when we expose our bone to exceedingly high demands without allowing for adequate rest, resulting in bone being broken down quicker than it is rebuilt. At first, we may get a stress reaction, where inflammation can be found at the site of overload. If the demands on the bone continue to exceed its capacity without allowing for recovery, it may result in a stress fracture.

Conducting a subjective exam for tibial stress injuries

A patient with a BSI may have had an insidious onset of pain, sharp pain upon impact, and gets pain after loading or at rest, frequently at night. In our subjective exam, we need to be mindful of not just the patient’s presentation, but also their story. Does the history align with the mechanism of injury and are there risk factors present that may make a BSI more likely? Here are some key areas to explore:

1. Training load: A sudden increase in training distance, intensity, or frequency can lead to BSI. For example, going from 30 to 70 kilometers per week in a short period increases the risk of injury.
2. Energy availability: Patients with a Relative Energy Deficiency in Sport (RED-S) are much more likely to suffer a BSI due to a lack of an energy supply that could be utilised for bone healing.
3. Pain onset and progression: Pay attention to the timeline of the pain. Initially, the pain may be mild and subside with rest. However, as the injury progresses, the pain becomes more intense and persistent, even at rest.
4. Activity type and intensity: Runners are among some of the most likely to suffer a BSI, partly due to the repetitive cycles of bone loading.
5. Previous injuries: A history of previous stress fractures increases the risk of future BSI.

Differential diagnoses

While medial shin pain is often a hallmark of tibial stress injuries, other conditions can present with similar symptoms. It is essential to differentiate between the following:

• Medial Tibial Stress Syndrome (MTSS)
• Medial calf strains, either of the gastrocnemius or soleus
• Neurological pathologies, like lumbar radicular pain or peripheral neuropathies
• Compartment syndrome

Here is a clip from Beau’s Case Study on how to differentiate between these various conditions:

Objective examination for tibial stress injuries

Once the subjective exam is complete, an objective exam can help to rule in a suspicion of a tibial BSI. While this list is not comprehensive, here are some key considerations for objective testing:

1. Progressive calf loading: During our assessments, we can progressively put more load through the bone in an attempt to reproduce symptoms. Our muscles exert stronger forces on our bones than ground reaction forces, so we can put load through the bone with simple calf raises. At first, they can be completed by starting with a lower peak force and a lower rate of loading (slow, two leg calf raises), and progressing to larger peak forces (by moving to single leg calf raises) and a faster rate of loading (calf raise pulses at increasing speeds).
2. Hop test: After calf raises, and especially if they are pain-free, you can move on to hop testing, a way to achieve even larger peak forces at a faster rate. You can first begin with two leg mini jumps before moving to slightly larger jumps and eventually, a single leg hop. A positive test, where symptoms are reproduced, can strongly suggest a tibial stress fracture.
3. Palpation: Carefully palpate the shin, focusing on the anterior, anterior medial, and posterior medial regions of the tibia. These areas are most commonly affected by tibial stress injuries.

It’s commonly believed that if the length of palpated tenderness is larger than 5 centimeters, then the injury is unlikely to be a BSI. However, in the below clip from his Case Study, Beau dives into the science and offers some more in-depth advice:

It’s important to remember that objective testing is not perfect. Objective tests in isolation should not be used to rule out BSIs. A good history is key, and as Beau says, “BSI patients are guilty until proven innocent”. The risk is too high to misdiagnose these patients, so when in doubt, rule it out with imaging!

Imaging for BSIs: When to use X-Rays and MRIs

Imaging plays a crucial role in confirming the diagnosis of tibial stress fractures. In low-risk cases, the clinical presentation and physical tests can sometimes be enough to guide treatment decisions. However, if there is significant concern about a potential stress fracture or the athlete’s symptoms are severe, imaging is warranted.

• X-rays are the first line of imaging for most suspected BSIs. They are inexpensive, quick, and can detect more severe fractures. However, they may not always identify early-stage BSIs, especially in the bone’s soft tissue. Interestingly, a repeat X-ray 2-weeks after an initial one can greatly increase their sensitivity.
• MRIs are more sensitive and can detect BSIs earlier, even in the absence of a visible fracture. MRIs may be a better choice if an X-ray was negative, if the BSI is at a high-risk site, if the patient is at a higher suspicion of a BSI due to something like RED-S, or if the patient has an event in life (like an upcoming race) that necessitates a more concrete answer.

Another benefit of MRIs is that the results can be used to inform our patients’ prognosis for returning to running and full activity. Here is a clip from Beau’s Case Study in which he explains what different MRI grades tell us in terms of prognosis for tibial BSIs:

Wrapping up

Tibial stress fractures are a serious concern for runners, but with early diagnosis and appropriate management, many athletes can make a full recovery. Due to their prevalence and severity, you should assume a runner with shin pain has a BSI until proven otherwise. Hopefully this blog has helped you with your confidence with assessing tibial BSIs!

If you need more guidance in assessing and treating this condition, make sure you check out Beau’s full Case Study.