As with any sports medicine condition, the athlete's history is the critical starting point in sorting out the problem. In exertional lower leg pain, it is no different. There are three main conditions that cause exertional shank pain, these being: medial tibial periostalgia, stress fracture, and chronic exertional compartment syndrome. Less frequently, and not to be missed, is popiliteal artery entrapment. Of course, tumours and infection need to always be in the back of our minds.
So, what differentiates these conditions with respect to history?
Tibial periostalgia pain
This is usually pain felt along the medial border of the tibia which:
- May be present early in the run
- Decreases as runner warms up
- Aches post exercise for up to a few hours
- May be present the next morning.
- Tends to occur when there has been a significant relative increase in activity or a change in footwear.
Tibial Stress fracture
This is characterised by gradual onset shin pain aggravated by exercise over days to weeks. It is often after a rapid increase in running/training load and may also correspond to changes in footwear or load pattern. The pain will come on within the first few steps of a run and worsen through the run, often stopping the athlete. There is often more severe post-exercise ache which can go into the evening and may, at its worst, wake the athlete.
Chronic Exertional Compartment syndrome [CECS]
The hallmarks of CECS are:
- Pain that may come on after 20-30 minutes into the run and can affect the anterior compartment, deep posterior compartment and to a lesser extent the peroneal compartment.
- As the condition worsens over time, the pain comes on earlier and more severely.
- Pain is induced by exercise that resolves relatively quickly on cessation.
- Resolution of symptoms usually follows a relatively consistent pattern over minutes to hours (rarely days) after exercise.
- About 20-30% of athletes will experience numbness into the foot or lower shin.
- If the athlete runs on consecutive days the onset of the pain shortens and the severity worsens.
- Rest from exercise over a few weeks can give a period of relatively pain free running on resumption of exercise, but the pain increases again over the ensuing weeks on continuing exercise.
- CECS may coexist with other forms of exercise-induced extremity pain, and these problems may significantly blur the clinical presentation.
In relation to the rarer popliteal artery entrapment:
- Pain is felt in the calf and is related to the intensity of the exercise rather than duration.
- There is a very rapid resolution of the pain when stopping.
- The pain doesn’t worsen if exercises day to day.
- The pain can be associated with a cold extremity when athlete removes the shoe.
So, the key is listening to the athlete, and then examining and imaging accordingly...but the history is paramount. Of course, there are other less common conditions that may need considering, but the four mentioned account for most of the chronic exertional pain the athlete complains of.