Stress fractures of the lower leg

Previous blogs in this lower leg series have discussed exertional lower leg pain with inflammatory features (medial tibial stress syndrome (MTSS)  / ‘shin splints’) and those with features of crescendo pain with definitive improvement upon cessation of activity (chronic exertional compartment syndrome).

One other subset of exertional lower leg pain however is that of bone stress.

As mentioned in earlier articles, there may often be a degree of overlap between these three entities (and a fourth less common condition being popliteal artery entrapment syndrome – PAES), rendering diagnostic challenges at times for treating practitioners.

Learn more about stress fractures in general here.

Stress fractures are often also referred to as fatigue fractures, coming about from excessive loading of bones with normal mineralisation (bone density).

Another group of patients (typically older patients, more so females, or patients with chronic medical conditions) can suffer from insufficiency fractures, whereby an acceptable amount of load can result in fractures to those with abnormal, osteoporotic bone. In the lower leg, this later group of insufficiency fractures can often be seen in the upper third of the tibia and is likely contributed to by coronal plane angular deformities (valgus/varus) in the older population due to arthritic change in the knee joint. (1)

In runners, and all sports involving a large amount of running or jumping, stress fractures of the lower leg are commonplace.

Stress fractures in general account for up to 20% of attendances to sports medicine clinics and of these, tibial stress fractures make up half of cases, in particular in those athletes participating in high impact and intensity running based activity.

In 16% of cases, tibial stress fractures are bilateral.

In the adult population, most fractures are typically situated posteromedially, in the mid to lower thirds of the tibia, where compressive forces are caused by posterior muscle contraction with running .(2)

There are other stress fracture variants of the tibia (some being much higher risk fractures – see below) and the fibula also can be affected – typically again in the mid to lower third.

The distinction between medial tibial stress syndrome and tibial stress fractures is often blurred and difficult to distinguish between clinically and many believe the former to be an early phase within what is a continuum that culminates in stress fractures and overt cortical breach.

Whilst in most cases of MTSS (at least in its earlier stages), subjects can ‘warm into’ activity and then report pain upon cooling down again, those with stress fractures typically report pain that worsens with activity and eases with rest.

Early on with bone stress, pain may commence towards the end of or after activity. As the injury moves through the spectrum of severity (provided there is not adequate rest for bone healing), pain onset will typically be earlier in activity, may be more severe, and may persist for longer after activity ceases.

With established lower limb stress fractures, pain may be present with activities of daily living, and may wake patients at night from aching.

Examination will usually elicit an area of specific localised tenderness at the site of tibial or fibular stress facture, as opposed to typically a more diffuse area of posteromedial tenderness seen with MTSS / periostitis.

Pain can be elicited with the use of a tuning fork – creating unpleasant vibrations localising to the site of bone stress.  In the majority of cases, tenderness and pain will be felt to the posteromedial border of the tibia.

Pain that localises to the anterior tibial cortex or medial malleolar region are cause for heightened concern and potentially indicate a high risk stress fracture, necessitating specialist consultation with a sport and exercise medicine physician.

Investigation is not routinely required for suspicion of lower limb stress fractures and diagnosis can often be made through a carefully obtained history and examination localising pain to a specific region.

Some cases will benefit from investigation in order to categorise the severity of an injury and anticipated time required for return to their chosen sport / recreation.

Other cases may require investigation if there are atypical features in the presentation.

X-rays can be normal if symptoms have only been present for a few weeks as periosteal reaction (new bone formation as part of the healing response) from osteoblastic activity takes time to appear.

In such cases, MRI is the investigation of choice as it quantifies periosteal or marrow cavity oedema, can confirm the presence of an associated cortical breach / stress fracture, can provide other information in the case of an alternative diagnosis, and importantly, is free of ionising radiation.

Occasionally, if further information is needed to aid decision making for management, CT scan may be requested.

As mentioned above there are two particular stress fractures in the lower leg that are cause for concern – the anterior tibial cortex stress fracture (a horizontally orientated ‘dreaded black line’ mid way down the tibial diaphysis on x-ray) and the medial malleolar stress fracture.

Both of these variants have been shown to demonstrate poor healing potential with conservative measures and often require surgical intervention to internally fix the fracture and prevent propagation into complete fractures.

Referral to a sport and exercise medicine physician is highly advisable if there is clinical suspicion for either of these two variants.

The cornerstone of management for lower limb stress fractures (like all stress fractures for that matter) is an adequate rest period to allow bone healing and reinforcement at the fracture site, a progressively graduated return to impact activity along with attendance to any predisposing or precipitating issues that can often be clearly elicited in a carefully obtained history.

There will in most cases be a sudden increase in either or both of volume or intensity of impact activity, a change in running shoes or terrain, or a preceding injury or region of stiffness that contributed to overload.

All of these factors must be borne in mind for prevention of recurrences.

Attendance to biomechanical issues such as hyperpronation, great toe MTPJ stiffness, hip joint range limitation and running biomechanics is also imperative.

Sometimes formal running assessment on a treadmill can be of great benefit and subtle changes to running technique can result in significant gains in running efficiency and  improvements of force dissipation with foot strike, in turn markedly reducing the chance of further bone stress injury and lower limb overuse injuries in the future.

Where subjects are unable to walk without pain, periods of ambulatory rest in a CAM boot for 2-6 weeks can be highly beneficial, whilst still allowing removal for sleep, personal hygiene and non impact cross training.

Generally there is no role for anti-inflammatory medications and some reports even suggest these may delay bone healing.

Standard analgesics (eg Panadol / Panadeine) coupled with rest are usually more than sufficient to control pain.

In most cases, your practitioner will recommend continued pain free non impact cross training to maintain general fitness and muscle tone, though in some cases of higher risk, patients may be advise strict rest.

Some studies suggest low intensity pulsed ultrasound (LIPUS) to be beneficial in stress fracture healing (3, 4), whilst others do not support these findings.

Younger athletes with recurrent stress fractures should consider the possibility of energy deficiency states leading to impaired bone density and consultation with a dietician is always prudent to assess caloric intake and diet in general.

In recurrent multi-regional stress fractures or patients of older age (>40), consideration should be given to investigation of bone density and management of any derangements found.

Dr Stuart Down is a Specialist Sport & Exercise Medicine Physician and has over 15 years of experience dealing with stress fractures and all manner of other activity-related injuries and conditions.

Lifecare Prahran Sports Medicine is close to suburbs including Malvern, South Yarra, Toorak, Armadale, St Kilda East, Caulfield, Richmond and Hawthorn, and has early and late appointments for all your Sports Medicine and Physiotherapy needs.

1. Martin LM, Bourne RB, Rorabeck CH. Stress fractures associated with osteoarthritis of the knee. A report of three cases. J Bone Joint Surg Am. 1988 Jun; 70(5):771-4.
2. Matheson GO, Clement DB, Mckenzie DC, Taunton JE, Lloyd-Smith DR, MacIntyre JG. Stress fractures in athletes. A study of 320 cases. Am J Sports Med 1987; 15:46-58.
3. Yadav YK, Salgotra KR, A Banerjee. Role of Ultrasound Therapy in the Healing of Tibial Stress Fractures. Med J Armed Forces India. 2008 Jul; 64(3): 234–236.
4. Uchiyama Y1, Nakamura Y, Mochida J, Tamaki T. Effect of low-intensity pulsed ultrasound treatment for delayed & non-union stress fractures of the anterior mid-tibia in five athletes. Tokai J Exp Clin Med. 2007 Dec20;32(4):121-5