Last post we learned about stress fracture, and heard Sally’s story. Not being able to run made her a bear with a sore head! This post, I want to show you how to avoid winding up in Sally’s shoes, and what to expect if you do ever find yourself there.

How do I know if I have a stress fracture?

Typically pain from a stress fracture comes on towards the end of activity, which is the opposite of tendinopathy and other soft-tissue issues which tend to improve with activity. The more advanced a stress fracture is, the earlier pain will occur in an activity, and the longer it will last. The bone is typically tender to touch, but not all bones can be physically palpated. Typically those who can jump or hop without pain have a lower likelihood of a stress fracture, but having some tenderness with that activity is still not a guarantee you have a stress fracture.

If you are experiencing pain during exercise, it is a good idea to see a health professional to find out if you might have a stress fracture or other injury. If your pain persists or gets worse with weight-bearing activity, that is an indicator that you may have a stress fracture.

MRI is the gold-standard in diagnosis of stress fractures as, it has good sensitivity and specificity, it can pick up inflammatory signs, and also can help differentiate between other soft tissue structures¹. In addition, MRI is overall a much safer procedure than other options as there is no radiation exposure. While an X-Ray (plain radiology) will show most traditional fractures, it will miss the vast majority of stress fractures. In-fact in the early stages of stress fracture (2-8 weeks) it will detect only 10%¹. Other methods can be used such as radionuclide scanning, which is very sensitive (rules stress fracture in or out) but not very specific (i.e. exact location, and severity). Computed Tomography (CT) is more sensitive than plain radiology and better deliniates a fracture line. However, CTs also produce a number of false negatives. I have typically seen CT used as an option where the MRI is contraindicated, or surgery is required and they want a better 3D view/impression of the fracture line and the bone. Ultrasound scanning may be useful for the surrounding soft tissue structure (e.g. detect tendinopathy), but cannot well-image the deeper bones.

With respect to diagnosis, there are no comprehensive guidelines for best timing of imaging (i.e do you need to get imaging as soon as you see the doctor, or should it be a certain time after onset). As with any musculoskeletal injury, in the absence of specific caution or malignancy, early imaging could actually be counter-productive as it could highlight variances in anatomy that are not related to your pain (e.g. a disc bulge that is part of normal aging, but is internalized by the patient as a weak point even if not stressed as such by their physician).

What are the risk factors for stress fracture?

• Previous stress fractures²
  • If you’ve had a stress fracture before, you already know what the onset of this injury feels like! Be extra careful to monitor your training load and pain levels, because you are at increased risk of developing another stress fracture.

• Changes in training
  • Even seemingly innocuous changes can sometimes bring on a stress fracture. This is one reason I take a detailed training history in my intake forms, and then ask even more questions while I am evaluating a patient. Understanding this not only tell us why the fracture might have occurred, but also allows us to best know how to relatively-reduce loading and allow for healing. This historical approach also yields great results for other injuries, so if you see a physical therapist or a doctor for a sports-related injury, they should be asking about your training history! For more on loading and injury see these blogs (ACWR blog, tapering blog).

• Being female
  • No, it’s not fair, but female athletes are 2-3 times more at risk of stress fractures³. Females who had late onset of menstruation (age ≥15 years)  have 5 times the risk of stress fracture, and those with an irregular or absent period have 3 times the risk; in these cases, it may be beneficial to do diagnostics for bone density and hormone levels.

• Eating disorders
  • Eating disorders contribute to various nutrient imbalances and can be contributory to low BMI, of which a score of 19 or less has been linked to stress fracture. You can check your BMI here at the National Heart, Lung, and Blood Institute. Nutrient imbalances is also one possible reason that tibial (shin) stress fractures have been seen to be increased in those who have narrower tibia³.

• Genetics
  • Even with some of these identifiable and actionable risk factors, some may also be fated towards stress fractures and other bone issues by their genes⁶.

What can I do to reduce my risk of getting a stress fracture?

• Cross-training will load the joints up differently. Many runners will try cycling and swimming or the gym for their cross training. There is some suggestion that the bone size can increase when loading is such that homeostasis leads to new bone formation. It has been shown in children⁴ and adults⁵ that playing ball sports, where there are multidirectonal stresses, encourages new bone formation.
• The acute:chronic workload ratio (ACWR) is a well evidenced way of managing load. If you keep your training between the top and bottom ends (0.8-1.3) the risk of injury is lower. Combine this with sensible pain monitoring, and other methods (Session RPE (Rating of Perceived Exertion) – We will blog about this soon!) and you have a great way of monitoring load.
• A balanced diet will help to reduce vitamin/mineral contributions to stress reaction and fracture. You need ensure that you are eating a healthy, varied diet, and taking in enough calories to support your body weight and activity levels.
• Correct biomechanics, including cadence (we have a blog about this soon!), stance width, stance length, excessive hip adduction. Oftentimes, stress fractures can occur when one part of the body is being overloaded due to poor biomechanics; correcting this will spread the load appropriately and help protect you against future injury. To do this in an objective and safe way, a professional video analysis is worthwhile as footage can be taken months later and compared. This is the type of video analysis we offer and have seen excellent results with local runners both in improving performance, reducing risk and more efficiently rehabilitating injury.

OK, if I have a stress fracture what can I do to treat it?

Initial treatment is symptom management, which could include relative-rest, medication, and ice. It might include medication, or supplementation for mineral imbalances. Relative rest would mean replacing running with cycling, or aqua-jogging for cardio. If an athlete cannot walk relatively painfree they may be immobilized (e.g. walking boot). While under relative rest, the athletes’ movement patterns can be analyzed and addressed. E.g. trunk and leg control during a single leg squat.  Addressing these movement patterns can be done via specific exercises and pain should be used as a guide for progression.

Graduated return to sport is variable depending on location of stress fracture and a host of other factors. I typically use a hop test in standing and then from a step to determine if a person is up to starting to run. When running is reintroduced it would be every other day initially and build up should be gradual.

Once an athlete has returned to some normalcy with running it is worth reviewing technique as this may have led to the stress fracture in the first place. In my practice I use professional-grade video analysis to help look at the various characteristics of a runner’s gait and look at how to optimize loading. I find it very useful as it is very difficult to see all that happens with the naked eye or ipad.  A recent meta-analysis of systematic reviews⁸ found that loading rate of vertical ground reaction force was increased in those who have stress fractures. This sounds complicated, but consider that muscles produce movement energy at various angles and magnitudes at different parts of the running cycle. It is thought that those who have or are prone to developing stress fractures deploy too much movement energy in a vertical direction rather than a forward direction. This same study suggested that a reduction of the vertical loading rate by 10-15% can reduce the risk and prevent stress fractures. Two other factors that increase vertical loading rate are heel striking⁹ and low cadence¹⁰. Thankfully, we typically see that when you increase cadence the athlete moves along a continuum towards mid and forefoot strike, so these two factors are relatively easy to change! However, I will note that these changes should be done gradually, and usually there are things to consider, so this should not be the only intervention. Forefoot and barefoot running have been shown to reduced vertical loading, and for this reason some people have switched to barefoot running. However, not everyone wants to run barefoot, so minimalist shoes have become popular. However, with this switch we have seen an increase in metatarsal stress fractures which is believed to be due to increased forefoot pressures¹¹. As such a switch to minimalist shoes should be greeted with caution and likely should be introduced gradually.

In conclusion, stress fractures are very treatable but can become a serious issue if not taken seriously. The sooner they are diagnosed, the sooner they can be treated and the sooner you can return to activity. A certain proportion of stress fractures can likely be prevented and this speaks to the importance of having good training plans, effective loading, and efficient gait. I have found that competitors in some sports are more likely to get a professional opinion sooner rather than later. With running, being a relatively economical sport and typically having a strong community, we typically see alot more self/group diagnosis and treatments.  As such, runners often leave it later (or too late) to get professional attention. I have not seen a Kevin Wade type injury with runners, but it is entirely possible this could occur. I encourage you to know the risk factors, try to reduce those that you can, and take any symptoms seriously.

Stay clear of stress fracture, be a happy runner!

References

1. Wright AA, Hegedus EJ, Lenchik L, Kuhn KJ, Santiago L, Smoliga JM. Diagnostic Accuracy of Various Imaging Modalities for Suspected Lower Extremity Stress Fractures: A Systematic Review With Evidence-Based Recommendations for Clinical Practice. Am J Sports Med. 2016;44(1):255-63.
2. Wright AA, Taylor JB, Ford KR, Siska L, Smoliga JM. Risk factors associated with lower extremity stress fractures in runners: a systematic review with meta-analysis. Br J Sports Med. 2015;49(23):1517-23.
3. Nunns M, House C, Rice H, et al. Four biomechanical and anthropometric measures predict tibial stress fracture: a prospective study of 1065 Royal Marines. Br J Sports Med. 2016;
4. Tenforde AS, Sainani KL, Carter sayres L, Milgrom C, Fredericson M. Participation in ball sports may represent a prehabilitation strategy to prevent future stress fractures and promote bone health in young athletes. PM R. 2015;7(2):222-5.
5. Mohr M, Helge EW, Petersen LF, et al. Effects of soccer vs swim training on bone formation in sedentary middle-aged women. Eur J Appl Physiol. 2015;115(12):2671-9.
6. Varley I, Hughes DC, Greeves JP, et al. RANK/RANKL/OPG pathway: genetic associations with stress fracture period prevalence in elite athletes. Bone. 2015;71:131-6.
7. Fredericson M, Jennings F, Beaulieu C, Matheson GO. Stress fractures in athletes. Top Magn Reson Imaging. 2006;17(5):309-25.
8. Van der worp H, Vrielink JW, Bredeweg SW. Do runners who suffer injuries have higher vertical ground reaction forces than those who remain injury-free? A systematic review and meta-analysis. Br J Sports Med. 2016;50(8):450-7.
9. Almeida MO, Davis IS, Lopes AD. Biomechanical Differences of Foot-Strike Patterns During Running: A Systematic Review With Meta-analysis. J Orthop Sports Phys Ther. 2015;45(10):738-55.
10. Willy RW, Buchenic L, Rogacki K, Ackerman J, Schmidt A, Willson JD. In-field gait retraining and mobile monitoring to address running biomechanics associated with tibial stress fracture. Scand J Med Sci Sports. 2016;26(2):197-205.
11. Bergstra SA, Kluitenberg B, Dekker R, et al. Running with a minimalist shoe increases plantar pressure in the forefoot region of healthy female runners. J Sci Med Sport. 2015;18(4):463-8.