Bony Stress Injuries and Pre-Season Training

Andy Chalmers

January 19, 2022

Following on from our previous newsletter on preventing pre-season injuries, we’ll take a greater look at bony stress injuries and understanding their relationship to the pre-season for many of the recommencing local sports, as well as commonplace in other individuals such as runners and endurance athletes.

What:

Bony stress injuries are overuse injuries, which represent the failure of bone to withstand repetitive loading, leading to structural fatigue and potentially damage. In simplifying the pathophysiology of this occurrence – mechanical forces (i.e physical activity) causes adaptive changes as well as microdamage to the internal and external microstructure of our bones. When adequate rest/recovery is not provided in conjunction with ongoing high-loading or impact activities, effectively, our bones may not be able to repair at the same rate at which the adaptive changes are occurring.

Bone stress injuries may be placed on a three-stage continuum (Kiuru et al., 2004).

  • Stage 1 ‘Bone strain/stress response’: there are signs of bony stress on medical imaging but the athlete is not experiencing pain
  • Stage 2 ‘Stress reaction’: there is now localised pain on palpation, and is aggravated with sporting activity
  • Stage 3 ‘Stress fracture’: where a fracture or break in the bone develops, evident on medical imaging, painful localised palpation, and often even painful weightbearing.

Where:

Most commonly, bony stress injuries are seen on the inside of the tibia, fibula, navicular, metatarsal or carpal bones of the foot, or neck or shaft of the femur.

Stress Fracture Assessment & Treatment (2021). Retrieved from https://newcastlesportsmedicine.com.au/bone/stress-fracture/

Examination:

On examination, a thorough subjective history will be important in diagnosis. This will look for training load errors such as large spikes in training load, pain patterns – which may include pain at rest, worsening pain with activity or night pain, as well as risk factors for bony stress injuries such as calcium or vitamin D deficiency, or menstrual irregularities. Palpation, where applicable, will reveal focal tenderness, and loading tests such as single leg hopping or fulcruming will be provocative. Ultimately, if a bony stress injury is suspected, MRI imaging forms the gold standard method for diagnosis. (Tenforde et al., 2016).

Risk factors:

Risk factors for bony stress injuries can be classified as either biological or biomechanical factors. Biological factors include:

  • previous bony stress injuries
  • osteoporosis, osteopenia or low bone mineral density
  • medication history including steroids and anti-depressants
  • poor diet and nutrition which includes low calcium and vitamin D intake, stress
  • Relative Energy Deficiency in Sport (RED-S). (Wright et al., 2015).

RED-S is a condition in which an athletes available energy supply does not meet the energy demand of the body, leading to weakening or injury of the system (Mountjoy et al., 2018). Look out for a more in-depth blog on RED-s on our website in the future.

  • Biomechanical factors include:
  • training load errors
  • biomechanics including running technique
  • footwear and training surfaces
  • muscular strength and endurance.

Management:

Management of these injuries then involves looking at the causative factors for the injury – as per the previous subjective history, controlling the pain, conditioning, axial loading, and finally return to sport. The length of time to return to sport is variable and dependent upon which stage of the continuum the bony stress injury is on, but should be progressed along a pain-free step-by-step rehabilitation timeline.

Initially, pain may be managed with removal of aggravating activity, weight-bearing modification, as well as Physiotherapy treatment to surrounding structures. NSAIDs should be avoided due to their potential negative effect on bone healing (Ziltener et al., 2010)

Athletes may then commence with pain-free conditioning including cycling, swimming, deep water running or anti-gravity treadmill tasks. Once an athlete is pain-free for at least 5 days with activities of daily living, graduated loading can then be implemented step-by-step as per general rehabilitation guidelines – although each step of rehabilitation should continue to be pain-free. This should include a combination of local and kinetic chain strengthening, balance, single-leg tasks, graduated plyometric activities and then progressing to jogging when appropriate. It is suggested that when returning to running, volume should be first restored before intensity, as the risk of bony stress injuries increases exponentially with increases in running intensity (Warden et al., 2021). Furthermore, it is suggested to consider a ‘skeletal reset’ week every 12 weeks. Finally, the athlete should be re-introduced to sport-specific activities, again, with each reintroduction being pain-free. It is important to note that setbacks in rehabilitation are common, and as such the key is to progress only as fast as the pathology will allow, within means of pain provocation.

Step Up w Knee Drive – an example of a a single leg balance and strengthening exercise.

Summary:

Similarly to previously discussed overuse injuries, a careful subjective history will also form the cornerstone to a diagnosis of bony stress injuries, with loading history being the key giveaway to diagnosis and subsequently being the foundation to management and prevention in the future. Once other causative factors have then been considered and accounted for, these athletes should then be exposed to varying forms of strength and conditioning loading tasks on a pain-free step-by-step continuum. Identifying any medical or biological factors is a key also for multi-disciplinary management.

ABOUT ANDY CHALMERS

Andy graduated from Latrobe University and has special interests in utilising exercise-based rehabilitation, acute and chronic sporting injuries, lower limb tendinopathies and loading issues. Andy has worked with AFL team Western Bulldogs and is the head physiotherapist for the North Geelong Warriors (NPL). He has qualifications in strength and conditioning and clinical Pilates, and is currently studying a double Masters in High Performance and Sports Physiotherapy

References:

Kiuru, M. J., Pihlajamäki, H. K., & Ahovuo, J. A. (2004). Bone stress injuries. Acta Radiologica, 45(3), 000-000.

Mountjoy, M., Sundgot-Borgen, J. K., Burke, L. M., Ackerman, K. E., Blauwet, C., Constantini, N., … & Budgett, R. (2018). IOC consensus statement on relative energy deficiency in sport (RED-S): 2018 update. British journal of sports medicine.

Tenforde, A. S., Kraus, E., & Fredericson, M. (2016). Bone stress injuries in runners. Physical Medicine and Rehabilitation Clinics, 27(1), 139-149.

Warden, S. J., Edwards, W. B., & Willy, R. W. (2021). Optimal load for managing low-risk tibial and metatarsal bone stress injuries in runners: the science behind the clinical reasoning. Journal of Orthopaedic & Sports Physical Therapy, (0), 1-28.

Wright, A. A., Taylor, J. B., Ford, K. R., Siska, L., & Smoliga, J. M. (2015). Risk factors associated with lower extremity stress fractures in runners: a systematic review with meta-analysis. British Journal of Sports Medicine, 49(23), 1517-1523.

Ziltener, J. L., Leal, S., & Fournier, P. E. (2010). Non-steroidal anti-inflammatory drugs for athletes: an update. Annals of physical and rehabilitation medicine, 53(4), 278-288.